# I came off



## Rooster1 (31 Oct 2016)

Here, watch as I slew myself across a road


View: https://youtu.be/TEqLKiRfeOs


Please note = I don't think I swore 

Enjoy


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## ruffers (31 Oct 2016)

Ouch


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## User6179 (31 Oct 2016)

Ouch !!
Did your tyre hit the white line ?


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## biggs682 (31 Oct 2016)

Rooster1 said:


> Here, watch as I slew myself across a road
> 
> 
> View: https://youtu.be/TEqLKiRfeOs
> ...




Any damage to you and machine?


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## Rooster1 (31 Oct 2016)

It was a little slippery out, and even up a hill the backwheel lost traction. I thought I braked just right but the back wheel just went under me. I need some grippier winter tyres. My own stupid fault. I learnt my lesson. Bike is fine. My arm and rear end was scuffed up a bit, and bruised. All good. Back on it.


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## Bollo (31 Oct 2016)

Ouchio! White paint or junction gravel? Glad it's nothing more serious than a few bruises. Take it easy and GWS.


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## mjr (31 Oct 2016)

Rooster1 said:


> I need some grippier winter tyres. My own stupid fault.


Just because they're called "slicks", you ain't meant to oil them! 

Glad it's only scuffs and bruises.


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## Johnno260 (31 Oct 2016)

ouch! you're ok I hope?


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## Pat "5mph" (31 Oct 2016)

Ouch!


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## CanucksTraveller (31 Oct 2016)

Ugh, wet white lines and gravel on junctions, the undoing of many before you. Get well soon.


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## steveindenmark (31 Oct 2016)

Ive done that

You feel stupid.

Now we can all feel stupid for you.

I hope you are OK


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## Salty seadog (31 Oct 2016)

Straight back in the saddle...good man. Heal quickly.


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## dave r (31 Oct 2016)




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## RoubaixCube (31 Oct 2016)

Taken that turn a little too quickly in those sort of conditions imo. 

Having been off my bike a few times and once in the rain i know how terrifying it feels to be sliding forward and not able to stop when youve got the brakes pulled right back. 

Except in my case i ended up smacking into the side of a car at 22mph before hitting the ground . Terrifying


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## Rooster1 (31 Oct 2016)

RoubaixCube said:


> Taken that turn a little too quickly in those sort of conditions imo.
> 
> Having been off my bike a few times and once in the rain i know how terrifying it feels to be sliding forward and not able to stop when youve got the brakes pulled right back.
> 
> Except in my case i ended up smacking into the side of a car at 22mph before hitting the ground . Terrifying




I did, I know. I committed to the turn, if i'd carried on straighter I would have had the car to contend with. Too fast, too wet.


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## johnnyb47 (31 Oct 2016)

Glad to see your ok buddy. That looked blooming painful. Can I ask what tyres you,ve got fitted.


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## Rooster1 (31 Oct 2016)

johnnyb47 said:


> Glad to see your ok buddy. That looked blooming painful. Can I ask what tyres you,ve got fitted.



Vittoria Rubino's 23c, no tread so to speak, lethal in the wet as i found out.

New Winter tyres are Schwalbe Marathons with a decent tread (I hope)


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## johnnyb47 (31 Oct 2016)

I hope you have better luck with your new tyres. Cycling clothing is great stuff to wear but it offers virtually no protection to gravel rash when you come off. The main thing is that you are ok though buddy.


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## Andrew_P (31 Oct 2016)

Boom!!! ouch!!!!


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## ianrauk (31 Oct 2016)

Rooster1 said:


> Vittoria Rubino's 23c, no tread so to speak, lethal in the wet as i found out.
> 
> New Winter tyres are Schwalbe Marathons with a decent tread (I hope)


It's nothing to do with tread. Slick cycle tyres can't aquaplane in wet weather. Slick or tread, the result would probably have been the same.


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## mjr (31 Oct 2016)

Rooster1 said:


> Vittoria Rubino's 23c, no tread so to speak, lethal in the wet as i found out.


Are they recent? Anyone know if the 23s are different? Rubino 25s I've bought recently have file-like shoulder tread that seems pretty good in the wet (unlike Zaffiro Slicks).


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## Mrs M (31 Oct 2016)

Ouch, hope you're ok


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## mjr (31 Oct 2016)

ianrauk said:


> It's nothing to do with tread. Slick cycle tyres can't aquaplane in wet weather. Slick or tread, the result would probably have been the same.


Depends what the rain has washed across the road, surely?


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## ianrauk (31 Oct 2016)

mjr said:


> Depends what the rain has washed across the road, surely?


Well aren't you a smart boy. Did you read my post properly?


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## mjr (31 Oct 2016)

ianrauk said:


> Well aren't you a smart boy. Did you read my post properly?


Yes. Why didn't you read @Rooster1's post well enough to notice the complaint was about "in the wet" rather than aquaplaning?


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## Smokin Joe (31 Oct 2016)

mjr said:


> Are they recent? Anyone know if the 23s are different? Rubino 25s I've bought recently have* file-like shoulder tread* that seems pretty good in the wet (unlike Zaffiro Slicks).



They're just a pretty pattern, they don't increase grip by one iota.


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## ianrauk (31 Oct 2016)

mjr said:


> Yes. Why didn't you read @Rooster1's post well enough to notice the complaint was about "in the wet" rather than aquaplaning?


And why didn't you read my post in the context of his post.. I'll make it simple for you. What ever the tyre he would have been using, the result would have probably been the same.


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## mjr (31 Oct 2016)

ianrauk said:


> What ever the tyre he would have been using, the result would have probably been the same.


So, in other words, the claim is that all tyre compounds and treads offer similar grip?


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## Theseus (31 Oct 2016)

Rooster1 said:


> Bike is fine. My arm and rear end was scuffed up a bit, and bruised. All good. Back on it.




Nice to see the priority is right. Glad to hear the bike is fine, your dents will heal.


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## ianrauk (31 Oct 2016)

mjr said:


> So, in other words, the claim is that all tyre compounds and treads offer similar grip?


On the road and in wet conditions yes. As some someone else has pointed out, tread pattern on road cycle tyres are mainly superfluous.


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## paraffinlamps (31 Oct 2016)

The tread on a bicycle road tyre has no effect with regards to traction as Ian and Joe have pointed out . Its mainly there as a placebo ( reassurance if you like ) . Some good information on Sheldons site http://www.sheldonbrown.com/tyres.html#tread
Looking at the video I would say it was the white lines that caused the rear wheel to breakaway . Its just one of those things that happens . You could probably do the same ride another day go around the corner at the same speed in the same weather conditions and be fine . Its the road conditions that caused it not the tyres lack of grip 
GWS Rooster


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## mjr (31 Oct 2016)

paraffinlamps said:


> The tread on a bicycle road tyre has no effect with regards to traction as Ian and Joe have pointed out . Its mainly there as a placebo ( reassurance if you like ) . Some good information on Sheldons site http://www.sheldonbrown.com/tyres.html#tread


And all three, plus Sheldon, seem to act as if we're cycling on lovely smooth roads with no soft squishy material or irregularities on them... oh and look, Sheldon says that tread helps with those, in the paragraph just above the one being pointed at!


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## Yellow Saddle (31 Oct 2016)

I hope the bike is OK.


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## subaqua (31 Oct 2016)

has @Fnaar been alerted to the thread title ........ 

and ouch .


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## paraffinlamps (31 Oct 2016)

mjr said:


> And all three, plus Sheldon, seem to act as if we're cycling on lovely smooth roads with no soft squishy material or irregularities on them... oh and look, Sheldon says that tread helps with those, in the paragraph just above the one being pointed at!



He actually says "Different tyre designs, particularly in the tread, may enhance or degrade traction in each of these cases. " the key words being enhance OR degrade .
As regards to smooth roads he actually says ". If you examine a section of asphalt or concrete, you'll see that the texture of the road itself is much "knobbier" than the tread features of a good-quality road tyre. Since the tyre is flexible, even a slick tyre deforms as it comes into contact with the pavement, acquiring the shape of the pavement texture, only while in contact with the road.


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## macp (31 Oct 2016)

How ya doing buddy hope your healing and well done for getting right back on


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## Smokin Joe (31 Oct 2016)

Anyway, regarding the OP; 

You ain't a proper cyclist till you've chucked a bike down the road.


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## mjr (31 Oct 2016)

Like most people with a view on this, I've read Sheldon's comments before. They still aren't going to settle the longstanding disagreement on the effects of tread for real-world road cycling.


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## Andrew_P (31 Oct 2016)

Just to add to the off topic, I thought it was the compound that altered the grip and rolling resistance?


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## macp (31 Oct 2016)

Smokin Joe said:


> Anyway, regarding the OP;
> 
> You ain't a proper cyclist till you've chucked a bike down the road.


Dammit really ?
Done it a time or two on a motorcycle so I should expect it any time soon


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## davidphilips (31 Oct 2016)

main thing is you are ok little bruised and bashed but still fit to cycle, after an accident like that not a single driver stopped to see you where all right perhaps no one noticed?


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## ColinJ (31 Oct 2016)

I'm glad that there were no serious injuries!

I've got Rubinos on my Cannondale and have not had any problems with grip, even in the wet. It is a case of adjusting your speed according to the conditions!

As pointed out by others above, tread is not going to help on a slippery road. Certain tyre compounds and lower tyre pressures may make some difference, but you shouldn't be pushing it that close to the limit.

Tread is very important OFF-road, when it can bite into soft, slippery surfaces such as soil. You wouldn't want to ride slicks on gnarly bridleways. Conversely, knobbly tread on mountain bike tyres can squirm about a bit when cornering at speed on tarmac so it is not ideal for that.


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## nickyboy (31 Oct 2016)

Tread is for water dispersal (not relevant for a bike tyre as it is too narrow to suffer from aquaplaning) or grip in the examples where the tread is significant (like CX or MTB tyres) and the surface particularly uneven and soft and as such the tyre cannot deform sufficiently to create grip

I ride Rubinos which have a little bit of tread on them but I know that it provides no additional grip when cycling on the road, just there for cosmetic effect. Basic physics will tell you how friction is created between the hard road and the soft tyre and tread plays no part in this


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## bozmandb9 (31 Oct 2016)

Interesting thread heist. I found this too:

http://www.bretonbikes.com/homepage...he-importance-of-tread-pattern-on-cycle-tyres


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## Yellow Saddle (31 Oct 2016)

bozmandb9 said:


> Interesting thread heist. I found this too:
> 
> http://www.bretonbikes.com/homepage...he-importance-of-tread-pattern-on-cycle-tyres


Good article.

For once.


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## Pale Rider (31 Oct 2016)

A slick tyre offers marginally more grip in the wet - on a hard, solid, surface - than a treaded one because there is a tiny bit more tyre in contact with the road.

Tread can help on loose surfaces, such as cinder track.

Compound comes into it, the tyre maker could produce a tyre that gripped better in the wet, but it wouldn't last long in the dry.

Schwalbe has a new four seasons tyre, but the tread on it is aimed at light snow and mud.

http://www.schwalbe.com/gb/newsreader/schwalbe-marathon-gt-365-the-all-year-marathon-gb.html


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## Yellow Saddle (31 Oct 2016)

mjr said:


> Like most people with a view on this, I've read Sheldon's comments before. They still aren't going to settle the longstanding disagreement on the effects of tread for real-world road cycling.


Start a new thread on this, post your hypothesis and we'll discuss.


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## PhilDawson8270 (31 Oct 2016)

Pale Rider said:


> A slick tyre offers marginally more grip in the wet - on a hard, solid, surface - than a treaded one because there is a tiny bit more tyre in contact with the road.



Unfortunately not really true. Surface area does not affect friction directly.


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## jonny jeez (31 Oct 2016)

Rooster1 said:


> Here, watch as I slew myself across a road
> 
> 
> View: https://youtu.be/TEqLKiRfeOs
> ...



One of the most shocking videos I've seen in a long while. How can anyone go out in daylight with cables that don't match?


Oh, sorry about the fall, hope you heal up quick.


Now go swap those cables 100 times


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## Moodyman (31 Oct 2016)

I understood that it was the road that gripped the tyre. I.e weighted tyre deforms and the coarse surface digs into tyre and creates friction. 

So I'm in the no tread camp.


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## PhilDawson8270 (31 Oct 2016)

bozmandb9 said:


> Interesting thread heist. I found this too:
> 
> http://www.bretonbikes.com/homepage...he-importance-of-tread-pattern-on-cycle-tyres



I took this whole thing with a pinch of salt when he fell into the trap of more rubber = more grip. That is not why race cars use slicks. It is for heat management.

Treaded tyres will very quickly overheat in dry conditions when used hard on a racetrack. During a lot of off season winter race track session you will see lots of people using tyres designed for the wet when it's dry. Since the tread movement increase temperatures, and the compound is generally much softer and thus becomes much hotter for the same loads.

He also only touched on wet and slick, yes wet is designed to clear water. But he totally missed the intermediate, which is cut into blocks. To help create heat in the tyre when the track is cold and wet, but with no standing water to disperse.


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## Salty seadog (31 Oct 2016)

Yellow Saddle said:


> Good article.
> 
> For once.



It had your favourite subject to blame, 'marketing' i happen to agree but I know I fall for it too, I'm sure we all do at times.


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## Pale Rider (31 Oct 2016)

PhilDawson8270 said:


> Unfortunately not really true. Surface area does not affect friction directly.



This illustrates the danger of applying theoretical physics too closely to a real world situation.

The experience of riders and drivers alike is that wider tyres offer more grip than narrow ones - the greater the contact area, the more the tyre grips.

And, going back to treads against slicks, Schwalbe give you an argument:

"On a normal, smooth road, even in wet conditions, a slick tyre actually provides better grip than a tyre with a tread, because the contact area is larger."

http://www.schwalbe.com/gb/profil.html


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## PhilDawson8270 (31 Oct 2016)

Pale Rider said:


> This illustrates the danger of applying theoretical physics too closely to a real world situation.
> 
> The experience of riders and drivers alike is that wider tyres offer more grip than narrow ones - the greater the contact area, the more the tyre grips.
> 
> ...



The inevitable appeal to authority 

I did actually email Schwalbe a while back regarding the validity of that statement and asked them how it is possible. They never did reply, despite several reminder emails.

https://www.cyclechat.net/threads/in-praise-of-titanium-and-spa-cycles.183930/post-3804044


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## Pale Rider (31 Oct 2016)

PhilDawson8270 said:


> The inevitable appeal to authority



Presumably, that's a smart-arse non response, but I genuinely have no idea what it means.

Anyhow, people can make up their own mind from experience and what the tyre makers say, setting that against your view.


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## raleighnut (31 Oct 2016)

Rooster1 said:


> Vittoria Rubino's 23c, no tread so to speak, lethal in the wet as i found out.
> 
> New Winter tyres are Schwalbe Marathons with a decent tread (I hope)


I'd watch Marathons for grip when they're new, once they are 'scrubbed in' they grip well but they need a fair few miles on em.


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## PhilDawson8270 (31 Oct 2016)

Pale Rider said:


> Presumably, that's a smart-arse non response, but I genuinely have no idea what it means.



Not a smart-arse response, but a tongue in cheek comment as this Schwalbe statement is regularly brought up as evidence when this topic is discussed, and I was certainly expecting it when I made my reply 

Appeal to authority, is when a statement from a source of perceived authority is used as evidence that the statement is correct.

In this case, the assumption that Schwalbe's statement about tyres is correct, as they are in the industry of selling tyres.

Their primary purpose though is to market, and sell the tyres.

As I say though, their statement does not stack up against physics too well, nor any academic source. Regardless of surface area (or contact patch), the coefficient of friction between the materials will remain the same. 

http://www.physlink.com/education/askexperts/ae140.cfm

As that link elegantly puts it, if you increase the surface area, you also decrease the pressure, this exactly offsets the increase in surface area, thus results in no increase in friction. You would need to increase surface area, AND the pressure.

The assumptions in the standard model tend to fail when the object is small enough to dig into the other surface, this isn't at the tiny level of road tyres, but when you have knobbly tyres on a loose surface.


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## ColinJ (31 Oct 2016)

I haven't had time to study all of THIS discussion but it looks interesting and I will return to it later!


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## HLaB (31 Oct 2016)

Rooster1 said:


> Here, watch as I slew myself across a road
> 
> 
> View: https://youtu.be/TEqLKiRfeOs
> ...



Ouchiees.

I found Rubinos towards the end of their life because there so hard wearing (can't remember a p'ture) were a bit skitty. Money was a bit tight when I had them so I lowered the pressure to mitigate the skittishness rather than buying a new tyre and never had a problem after that. What pressure are you running?


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## PhilDawson8270 (31 Oct 2016)

ColinJ said:


> I haven't had time to study all of THIS discussion but it looks interesting and I will return to it later!



A good discussion in that thread, with lots of very good points. Especially about friction not being simple, but I don't think it is directly relatable to a bicycle tyre, or most real world applications. After all the standard model behaves well when used in crash investigation, etc.

In my opinion, the biggest influence on grip on a road tyre is not the tread, but the compound.


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## gavroche (31 Oct 2016)

I also think the white paint on the road got you. No matter the tyre tread , the result would have been the same.


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## johnnyb47 (31 Oct 2016)

I think both sides of the camp have equal and valid reasons as to whether a slick or treaded tyre are the best. If you just go out on a ride for 10 miles , how many different road surfaces do you encounter. Nice and smooth , recently stone chipped to patched work quilt road surface's. All these various road surfaces we encounter will suit a treaded better and then a slick. There's no definitive answer as to what's the best tyre because are roads are not constant enough to cater for a particular type of tyre. If there's lying snow or you cycle though muddy conditions it a definite yes for treaded but on a clean public road it's anybody's guess at any given point of the highway as to what's the most suitable tyre. 
I'll just grab my tin hat now and hide behind to wall lol :-)


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## Yellow Saddle (1 Nov 2016)

johnnyb47 said:


> I think both sides of the camp have equal and valid reasons as to whether a slick or treaded tyre are the best. If you just go out on a ride for 10 miles , how many different road surfaces do you encounter. Nice and smooth , recently stone chipped to patched work quilt road surface's. All these various road surfaces we encounter will suit a treaded better and then a slick. There's no definitive answer as to what's the best tyre because are roads are not constant enough to cater for a particular type of tyre. If there's lying snow or you cycle though muddy conditions it a definite yes for treaded but on a clean public road it's anybody's guess at any given point of the highway as to what's the most suitable tyre.
> I'll just grab my tin hat now and hide behind to wall lol :-)


No need to hide, help is on its way. No lolling either, this is serious stuff.

Here's a rule of thumb for you wrt bicycle, motorcycle and aeroplane tyres.

*If the road is harder than the tyre, then the tyre requires no tread.
If the road is softer than the tyre, then the tyre requires tread.*

The various "types" of hard road you encounter has no effect on whether you need tread or not.


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## cyberknight (1 Nov 2016)

Rooster1 said:


> I did, I know. I committed Too fast, too wet.


He says that to everyone !

GWS.


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## Yellow Saddle (1 Nov 2016)

PhilDawson8270 said:


> In my opinion, the biggest influence on grip on a road tyre is not the tread, but the compound.



In m y opinion, that's a fact, not an opinion.


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## mjr (1 Nov 2016)

Yellow Saddle said:


> *If the road is harder than the tyre, then the tyre requires no thread.
> If the road is softer than the tyre, then the tyre requires thread.*


They all require thread, to hold the rubber into shape 

Seriously, I'm riding over leaf mulch on roads these days. Last month, it was harvest mud. In a few months, it'll be some other shoot. I'll keep on having a little tread, thanks.


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## Yellow Saddle (1 Nov 2016)

mjr said:


> They all require thread, to hold the rubber into shape
> 
> Seriously, I'm riding over leaf mulch on roads these days. Last month, it was harvest mud. In a few months, it'll be some other shoot. I'll keep on having a little tread, thanks.


I've fixed the tread in this thread. Thanks for pointing out.


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## Rooster1 (1 Nov 2016)

davidphilips said:


> main thing is you are ok little bruised and bashed but still fit to cycle, after an accident like that not a single driver stopped to see you where all right perhaps no one noticed?



The Saab pulling out did pause to check i was OK, I waved him an OK. By the time other cars were passing, I was upright and faffing about and not in obvious pain (aside from the general groaning noises I made).


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## nickyboy (1 Nov 2016)

PhilDawson8270 said:


> Not a smart-arse response, but a tongue in cheek comment as this Schwalbe statement is regularly brought up as evidence when this topic is discussed, and I was certainly expecting it when I made my reply
> 
> Appeal to authority, is when a statement from a source of perceived authority is used as evidence that the statement is correct.
> 
> ...



100% agree on the theoretical physics aspect that surface area contact doesn't influence frictional forces. However, you have to consider what is really going on when your tyre comes into contact with the road. Of course it deforms to "mould" to the shape of the road surface, that's the friction in principle. However what it also does is bounce over road surface imperfections and the down force is reduced and thus friction is reduced. So what influences the amount of "bounce"? How readily your tyre deforms and how hard the road surface imperfections are. Some tyre compounds will deform more readily than others so these will exert greater frictional forces

It is also true to say that if you pump up your tyres more and more, the surface area in contact with the road reduces. But also the tyre becomes less able to deform so friction is reduced this way. Less surface area in contact in this case results in less friction


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## Rooster1 (1 Nov 2016)

HLaB said:


> Ouchiees.
> 
> I found Rubinos towards the end of their life because there so hard wearing (can't remember a p'ture) were a bit skitty. Money was a bit tight when I had them so I lowered the pressure to mitigate the skittishness rather than buying a new tyre and never had a problem after that. What pressure are you running?



They are definately end of life, and as I said, even climbing a hill they were slipping. I maxxed out the tyre pressure but not sure what it is exactly.


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## Rooster1 (1 Nov 2016)

jonny jeez said:


> One of the most shocking videos I've seen in a long while. How can anyone go out in daylight with cables that don't match?
> 
> 
> Oh, sorry about the fall, hope you heal up quick.
> ...



Sorry about the cables, must sort.


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## Yellow Saddle (1 Nov 2016)

nickyboy said:


> 100% agree on the theoretical physics aspect that surface area contact doesn't influence frictional forces. However, you have to consider what is really going on when your tyre comes into contact with the road. Of course it deforms to "mould" to the shape of the road surface, that's the friction in principle. However what it also does is bounce over road surface imperfections and the down force is reduced and thus friction is reduced. So what influences the amount of "bounce"? How readily your tyre deforms and how hard the road surface imperfections are. Some tyre compounds will deform more readily than others so these will exert greater frictional forces



No, Surface area contact does influence friction. This contact is influenced both by tyre compound and by downforce. But "contact" is not as simple as as an area. 



nickyboy said:


> It is also true to say that if you pump up your tyres more and more, the surface area in contact with the road reduces. But also the tyre becomes less able to deform so friction is reduced this way. Less surface area in contact in this case results in less friction



No. The contact patch may shrink but pressure (downforce per area) between road and tyre increases and friction is equalised. The equation is almost perfectly balanced - as pressure increases (contact patch grows smaller) the friction increases.


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## Rooster1 (1 Nov 2016)

I am annoyed I did not go for the Graphene Vittorias now as a replacement 

*Vittoria Rubino Pro G+ Isotech Folding Tyre*


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## lutonloony (1 Nov 2016)

glad your OK apart from hurt pride. I find that I normally take a hoof down the tarmac when I have got new clothing on, thus ensuring it quickly matches the state of my old stuff with rips, tears and blood stains!!


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## nickyboy (1 Nov 2016)

Yellow Saddle said:


> No, Surface area contact does influence friction. This contact is influenced both by tyre compound and by downforce. But "contact" is not as simple as as an area.
> 
> 
> 
> No. The contact patch may shrink but pressure (downforce per area) between road and tyre increases and friction is equalised. The equation is almost perfectly balanced - as pressure increases (contact patch grows smaller) the friction increases.



Read what I said again. The issue is the level of hysteresis is different in different tyre designs. This, coupled with the fact that tyres under greater pressure are less prone to deformation per se results in more "bounce" (for want of a better word). The lack of deformation results in upward movement and this reduces downward force and thus friction


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## Yellow Saddle (1 Nov 2016)

nickyboy said:


> Read what I said again. The issue is the level of hysteresis is different in different tyre designs. This, coupled with the fact that tyres under greater pressure are less prone to deformation per se results in more "bounce" (for want of a better word). The lack of deformation results in upward movement and this reduces downward force and thus friction


You are confusing a bunch of things here.
Hysteresis relates to internal energy losses inside the tyre and other than the heat that it generates that influences the tyre compound, has no validity in the discussion here. 
Tyres under greater pressure are less prone to tyre deformation IN THE CASING. The internal pressure does not affect the tread's deformation. That remains constant.
Downforce does affect overall friction but not the coefficient of friction. But I'm not sure why downforce is even under discussion here. If there was any significant "bounce" as you put it, one would not be able to corner. Bicycles corner very well without the aid of suspension, so bounce is moot.


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## Ajax Bay (1 Nov 2016)

Back on topic, first of all hope your bike's OK, @Rooster1 that you're no more than a bit grazed and that you're back blasting the roads.
A day's gone since your post and many have wished you well. Thanks for posting the video: most of us have been somewhere there.


paraffinlamps said:


> Its the road conditions that caused it not the tyres


IMO the *reason* you lost the rear wheel on the white line was that *you were braking *(*see* second 03 (no brakes) and following two seconds of the video, quite firmly applied (both)) and you didn't release the levers as you crossed the white lines. You needed to slow down for the corner but you must not have brakes on or be significantly turning across white lines or metalwork, or if you must, expect that you may slide (and recover, because you're expecting it).
Off topic, on a normal asphalt/tarmacced road, tread or lack of it makes no difference to grip ( @bozmandb9 referenced article seems pretty good to me - post #44). Unreasonably high pressures in tyres [ @Rooster1 : I maxxed out the tyre pressure] will increase the likelihood of a bit of bouncing on rough road surfaces, more so at speed, of course, and that can make grip hazardous when necessary braking is added to the mix (ie to the the need to turn to follow the road). You need a combination of decent bike handling skills and a speed suitable for the road, its gradient, the sightlines, conditions and your skill/risk threshold. We can leave @mrj to tread on his road detritus on wide tyres with low pressures in. Others may just ride normal tyres and take note of the leaves, thread their way through, sitting well back up the hills to maximise weight on the rear wheel and thus the amount of power they can put down, before they slip.


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## Yellow Saddle (1 Nov 2016)

Moodyman said:


> I understood that it was the road that gripped the tyre. I.e weighted tyre deforms and the coarse surface digs into tyre and creates friction.
> 
> So I'm in the no tread camp.



Yes, but probably not the way you put it. The courseness at visual level is irrelevant. Tyres perform very well on smooth glass. It is the courseness at molecular level that, when the tyre squeezes into it, the contact area between the two is much larger than the contact path's surface area. Imagine squeezing into a brocolli floret and comparing the surface area of that "contact" area with that of the surface area of a sphere the same size as the piece of broccoli.

Friction is not mechanical in the interlocking sense of the word but electical in the positive attracts negative sense. Imagine an atom as an amoeba with only two components - a negatively-charged mush and a positively-charged mush. The two mushes are in free suspension and can move around. When the amoeba gets close enough to something similar, the negative mush moves to the cell's one end and the positive mush to the other end. Now the amoeba is polar. It will attract and stick to the other amoeba. 

The distance is crucial and in the nano scale. If the two amoeba are not very, very close to each other, they won't morph their polarity and attract. This is the Van der Waal's force and technically one of nature's weak forces.

But, Van der Waal is strong enough to provide the centripetal force that keeps your bike from sliding when cornering. It is strong because a very weak force was multipled by very, very close contact.


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## nickyboy (1 Nov 2016)

Yellow Saddle said:


> You are confusing a bunch of things here.
> Hysteresis relates to internal energy losses inside the tyre and other than the heat that it generates that influences the tyre compound, has no validity in the discussion here.
> Tyres under greater pressure are less prone to tyre deformation IN THE CASING. The internal pressure does not affect the tread's deformation. That remains constant.
> Downforce does affect overall friction but not the coefficient of friction. But I'm not sure why downforce is even under discussion here. If there was any significant "bounce" as you put it, one would not be able to corner. Bicycles corner very well without the aid of suspension, so bounce is moot.



At the risk of this becoming tiresome (see what I did there) for everyone, minimisation of the vertical component when you're cycling is critical to the amount of friction exerted between the tyre and the road. Increase in vertical up force reduces the down force and thus friction is reduced. Coefficient of friction is constant, force reduces so friction between two surfaces reduces. Bikes bounce, chatter, what ever you want to call it. This is caused in part by lack of deformation in tyres which in turn reduces the friction between tyre and road. Less deformation = more vertical movement = less down force = less friction


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## Ajax Bay (1 Nov 2016)

nickyboy said:


> Increase in vertical up force reduces the down force


What is this vertical up force, please? Surely the 'vertical up force' is the normal reaction (from both tyre contact points) to the weight of the bike and its rider (factored by any 'g' force effect of going into a dip) - the 'down force'. When one tyre bounces/chatters the other's taking the load (so therefore more grip if required).


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## nickyboy (1 Nov 2016)

Ajax Bay said:


> What is this vertical up force, please? Surely the 'vertical up force' is the normal reaction (from both tyre contact points) to the weight of the bike and its rider (factored by any 'g' force effect of going into a dip) - the 'down force'. When one tyre bounces/chatters the other's taking the load (so therefore more grip if required).



I don't think that, for example, reduced grip on the front compensated for by increased on the back is such a great thing, Anyway, enough of thread derailments


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## Ajax Bay (1 Nov 2016)

nickyboy said:


> I don't think that, for example, reduced grip on the front compensated for by increased on the back is such a great thing


Sorry - my abilities of comprehension have failed here ^^^^ (maybe some missing words). And what is the 'vertical up force that reduces the down force' of which you spoke.


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## cyberknight (1 Nov 2016)

Yellow Saddle said:


> In m y opinion, that's a fact, not an opinion.


I concur , changed tyres after a few of these sort of crashes even taking as slow as i could and i havent fell off since in the same conditions .


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## MichaelW2 (1 Nov 2016)

Wet paint, always aim for the gaps.My local Tesco has an entrace defined by a line of bricks jutting 1" up above the level of the tarmac. On the wide sweeping downhill entrance I almast came off from the bump.


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## HLaB (1 Nov 2016)

Rooster1 said:


> They are definately end of life, and as I said, even climbing a hill they were slipping. I maxxed out the tyre pressure but not sure what it is exactly.


If you maxxed out the tyre pressure you probably have them too hard.


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## Alan O (1 Nov 2016)

I've found this discussion of tyres very interesting - you folks clearly know a lot more about the theory and practice than I do.

But if I can offer one observation based on my own experience - the biggest factor that's affected my grip (when cornering, when on slippy surfaces, whatever) has not been my tyre tread, it's not been my tyre compounds, not the width, not the inflation pressure... it's been the nut on the saddle


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## Ajax Bay (1 Nov 2016)

Alan O said:


> the biggest factor that's affected my grip . . . [has] been the nut on the saddle


I'm having trouble with the nut on my old Brooks saddle, but only when standing out of the saddle. Since I'm invariably seated when cornering and braking - not a factor - for me.


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## Rooster1 (2 Nov 2016)

Old Tyre (RED) vs New


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## si_c (2 Nov 2016)

Rooster1 said:


> Old Tyre (RED) vs New



Nice  that Rubino doesn't look too worn though, be interesting to see how you feel about the new tyres, I propose a test ride


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## ianrauk (2 Nov 2016)

si_c said:


> Nice  that Rubino doesn't look too worn though, be interesting to see how you feel about the new tyres, I propose a test ride




Agreed. I would say there's plenty of life left in that tyre.


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## Rooster1 (2 Nov 2016)

si_c said:


> Nice  that Rubino doesn't look too worn though, be interesting to see how you feel about the new tyres, I propose a test ride



I fancy doing a stop test also, same road, same speed, brakes on, red tyres vs new tyres - see how far I go (in a staight line this time)


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## Rooster1 (2 Nov 2016)

ianrauk said:


> Agreed. I would say there's plenty of life left in that tyre.



i will run them again in the spring maybe


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## ColinJ (2 Nov 2016)

Rooster1 said:


> I fancy doing a stop test also, same road, same speed, brakes on, red tyres vs new tyres - see how far I go (in a staight line this time)


So, would that be on a damp road again ...? It is perfectly possible to lock your wheels up, skid and fall off on a straight, damp road if you overdo your braking!

You didn't fall off because your tyres were no good - you fell off because your riding was no good for the conditions and the same thing could happen in your brake test.

I think that you would be better off spending your time practising your bike handling skills. When I was learning to ride as a child I used to ride up and down the cinder track to a local club. I used to deliberately lock up the back wheel so I could get used to controlling rear wheel skids on its loose surface. (Don't even think about doing the same for the front wheel ... there are very few people who can recover when their front wheel goes from under them!)

I got to try out my bike handling very early in my Yorkshire riding 'career' when traffic lights at the foot of a steep local descent changed back to red after an unexpectedly short period on green. (The lights are on-demand only in that direction and give priority to traffic on the A646 below, but I didn't know that at the time.) The road surface was damp and I had not factored that in either! My emergency braking led to a rear wheel slide which I managed to get under control and I came to a stop just in time. I think that I would have gone down if it were not for all those skid sessions as a child.


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## Yellow Saddle (2 Nov 2016)

ColinJ said:


> I haven't had time to study all of THIS discussion but it looks interesting and I will return to it later!



Make time. It is the most layman-palatable piece of writing on tribology that I've seen in a long time. It is just a pity it didn't touch on lubrication in context - water on the road.

@Pale Rider. You and I exchanged words once on the linear nature (or not) of the inflation and contact patch relationship. There's a nice graph in there that deals with it.


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## Milkfloat (2 Nov 2016)

Slightly off topic - but I was led to believe that like for like, coloured tyres were less grippy than black. Is that just an old wives tale?


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## mjr (2 Nov 2016)

Milkfloat said:


> Slightly off topic - but I was led to believe that like for like, coloured tyres were less grippy than black. Is that just an old wives tale?


I'd not heard that one. I'd heard that black tyres withstand UV better than gum due to the black colouring, but I've no idea if that's true either.


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## Yellow Saddle (2 Nov 2016)

Milkfloat said:


> Slightly off topic - but I was led to believe that like for like, coloured tyres were less grippy than black. Is that just an old wives tale?


The stuff that makes MOST tyres black is carbon black. It is very fine pure carbon obtained by burning acetylene in oxygen. It's not posh to call it soot. Nevertheless, it was discovered probably 100 years ago that if you add carbon black to natural rubber, it makes for a very durable tyre and as it turned out, a grippy one too. 

Later on someone discovered you can create coloured tyres by adding coloured sand (silica) instead of carbon black. That created a tyre with lower rolling resistance and it because quite popular on bicycles. However, its performance and durability was poor enough for it to be banned on car tyres, hence our black rubber until today.

Most black bicycle tyres however are made from black silica. Companies who use carbon black like to brag about it and will add the magic word Carbon somewhere on the casing. 

Not all black is carbon.


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## Rooster1 (2 Nov 2016)

ColinJ said:


> So, would that be on a damp road again ...? It is perfectly possible to lock your wheels up, skid and fall off on a straight, damp road if you overdo your braking!
> 
> You didn't fall off because your tyres were no good - you fell off because your riding was no good for the conditions and the same thing could happen in your brake test.
> 
> ...



*I already said I know it was my riding. *


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## Alan O (2 Nov 2016)

ColinJ said:


> there are very few people who can recover when their front wheel goes from under them!


I've only ever had that happen to me once (well, twice, minutes apart). I braked on black ice and the first thing I knew about it was that I was lying on my back and the bike was sliding down the road.

I got up, walked the bike past what I thought was the extent of the ice, got back on and tried to pedal away...


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## ColinJ (2 Nov 2016)

Rooster1 said:


> *I already said I know it was my riding. *


*But despite that, you keep talking about your tyres ...*


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## ColinJ (2 Nov 2016)

Alan O said:


> I've only ever had that happen to me once (well, twice, minutes apart). I braked on black ice and the first thing I knew about it was that I was lying on my back and the bike was sliding down the road.
> 
> I got up, walked the bike past what I thought was the extent of the ice, got back on and tried to pedal away...


I've had it happen several times in 30 years. 3 times in one ride on black ice!!! A couple of times on mud, and at least once on wet leaves. Some near misses on gravel ...


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## Rooster1 (2 Nov 2016)

I won't be commenting further, bad luck


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## mjr (2 Nov 2016)

ColinJ said:


> I used to deliberately lock up the back wheel so I could get used to controlling rear wheel skids on its loose surface. (Don't even think about doing the same for the front wheel ... there are very few people who can recover when their front wheel goes from under them!)


Surely very few people recover when their back wheel goes from under them? By the time a skid has got to that point, you've probably lost, whichever wheel.

I've remained upright through a few front-wheel skids, often when I've a heavy load on the back or a trailer, but none got as far as the wheel going from under me. Probably still not the best idea to deliberately skid your front wheel, though.


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## Yellow Saddle (2 Nov 2016)

Rooster1 said:


> I won't be commenting further, bad luck


Sorry you have to go. Your video was really thought-provoking and I'm glad you posted it. With a slightly - dare I say Accy - slant to it it could have evolved into an anti-car thread again but it kinda swayed off course in a good way. It elicited some good debate and you never placed blame anywhere other than on your skill and/or luck at the moment. May I ask that you wipe your camera's lens more often and switch it to a higher frame rate when you sense excitement? I really wanted to see what happened with those brake levers moments before the slide.


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## Yellow Saddle (2 Nov 2016)

mjr said:


> Surely very few people recover when their back wheel goes from under them? By the time a skid has got to that point, you've probably lost, whichever wheel.
> 
> I've remained upright through a few front-wheel skids, often when I've a heavy load on the back or a trailer, but none got as far as the wheel going from under me. Probably still not the best idea to deliberately skid your front wheel, though.



If you lose traction whilst cornering - you lose it. One reason being that a skid induces even more lean. However, controlled rear wheel skids are very common. Fixies use it to scrub off speed and change direction - on tarmac. Trail riders use it to maneuver fast corners. Kids use it to show off and piss daddy off.

Front wheel skids are a different animal altogether. Firstly, it cannot be induced on good surfaces and on poor surfaces it is irrecoverable unless the surface is poor for just a very small area and it improves as the wheel moves into the better section. But scale is important here.


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## ColinJ (2 Nov 2016)

Rooster1 has probably got me on 'ignore' now, but apologies if my posts came across as critical - they were intended to be helpful! 

As for recovering from rear wheel skids ... I was referring to the straight line version.

Effective braking is normally done with the front wheel but when road conditions are slippery that really isn't a great idea because when things go wrong they go VERY wrong VERY fast.

If you have got yourself into a situation where you HAVE to brake and the road is slippery then you just have to go for the rear brake, and that can result in a rear wheel skid. That was what happened to me in the situation described above where I was descending a 10% hill with a wet road surface and suddenly found myself confronted by a red light and cars passing in front of me! I had misjudged the situation due to inexperience, but at least I had enough experience of rear wheel skids to get the resultant fishtailing under control and stop in time.

Nowadays, I play safe and assume that the lights will change, or even that somebody will jump the lights on the main road (which I now know they DO very frequently), so I slow down way before the lights in wet conditions.


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## Yellow Saddle (2 Nov 2016)

ColinJ said:


> Rooster1 has probably got me on 'ignore' now, but apologies if my posts came across as critical - they were intended to be helpful!
> 
> As for recovering from rear wheel skids ... I was referring to the straight line version.
> 
> ...



I think you will find it very difficult to skid the front wheel by braking in the rain. Front wheel only is far, far safer than using the back brake only.


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## ColinJ (2 Nov 2016)

Yellow Saddle said:


> I think you will find it very difficult to skid the front wheel by braking in the rain. Front wheel only is far, far safer than using the back brake only.


On a perfectly clean road surface, in a perfectly straight line, maybe. On a road surface with all sorts of greasy deposits on it, metal drain covers, painted white lines, and potholes to avoid ...


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## toffee (2 Nov 2016)

Yellow Saddle said:


> I think you will find it very difficult to skid the front wheel by braking in the rain. Front wheel only is far, far safer than using the back brake only.



Are you sure about that. My face took a fair beating from the road surface each time I went over the handlebars as a kid. The brakes on my current bikes are far better at stopping the wheels going round than the ones I had as a kid as well.

Derek


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## Yellow Saddle (2 Nov 2016)

toffee said:


> Are you sure about that. My face took a fair beating from the road surface each time I went over the handlebars as a kid. The brakes on my current bikes are far better at stopping the wheels going round than the ones I had as a kid as well.
> 
> Derek


Perhaps you missed the discussion about how you cannot skid the front wheel on good road surfaces by braking hard.

Read through here and perhaps reconsider your stance.

https://www.cyclechat.net/threads/braking-hard-with-rear-brake.182211/post-3755598


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## Yellow Saddle (2 Nov 2016)

ColinJ said:


> On a perfectly clean road surface, in a perfectly straight line, maybe. On a road surface with all sorts of greasy deposits on it, metal drain covers, painted white lines, and potholes to avoid ...


It is a mental thing drummed into you as a beginner cyclist.
If you are faced with two options under such conditions, you are still safer using the front brake, I would say. You could use the back brake and convince yourself that you could easily recover from the frequent slide-outs or you could use the front brake and not worry about slide-outs as much but when they happen you need not even attempt correction. Both are evil options. I choose the latter.


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## ColinJ (2 Nov 2016)

Yellow Saddle said:


> Perhaps you missed the discussion about how you cannot lock the front wheel on good road surfaces?


Don't you mean _'skid'_? 



Yellow Saddle said:


> It is a mental thing drummed into you as a beginner cyclist.
> If you are faced with two options under such conditions, you are still safer using the front brake, I would say. You could use the back brake and convince yourself that you could easily recover from the frequent slide-outs or you could use the front brake and not worry about slide-outs as much but when they happen you need not even attempt correction. Both are evil options. I choose the latter.


You are right in saying that the back wheel _is_ more likely to slip away, but I have recovered from it every time it has happened to me. Well, at least since I learned how to do that from my numerous cinder path practices. I have _NEVER_ got away with a front wheel going from under me!

Anyway, the proper solution is to try to avoid getting into the situation where heavy braking is needed in the wet.


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## Yellow Saddle (2 Nov 2016)

ColinJ said:


> Don't you mean _'skid'_?
> 
> 
> You are right in saying that the back wheel _is_ more likely to slip away, but I have recovered from it every time it has happened to me. Well, at least since I learned how to do that from my numerous cinder path practices. I have _NEVER_ got away with a front wheel going from under me!
> ...


Indeed, thanks. Will fix.


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## toffee (2 Nov 2016)

Yellow Saddle said:


> Perhaps you missed the discussion about how you cannot skid the front wheel on good road surfaces by braking hard.
> 
> Read through here and perhaps reconsider your stance.
> 
> https://www.cyclechat.net/threads/braking-hard-with-rear-brake.182211/post-3755598


Think you miss understood what I meant or probably I didn't explain properly. I don't see what stance I had either.

Anyway brake too hard from high speed and the chances are you are not going to stay upright, which ever brake you use.

Derek


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## EasyPeez (4 Nov 2016)

Yellow Saddle said:


> No need to hide, help is on its way. No lolling either, this is serious stuff.
> 
> Here's a rule of thumb for you wrt bicycle, motorcycle and aeroplane tyres.
> 
> ...



And how does tyre width play into this? All my instincts are telling me that it's time I changed my (Slick) 28mm 4seasons for my (treaded) 35mm marathon deluxe in order to reduce my chances of slip as the roads become wetter/icier, but am I actually better off sticking to the contis?


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## Yellow Saddle (4 Nov 2016)

EasyPeez said:


> And how does tyre width play into this? All my instincts are telling me that it's time I changed my (Slick) 28mm 4seasons for my (treaded) 35mm marathon deluxe in order to reduce my chances of slip as the roads become wetter/icier, but am I actually better off sticking to the contis?


That is a very good question and what's good for the good is not good for the gander. Cars being goose and bikes being gander, that is.

Lots is known about tyre width, particularly wrt racing cars. Racer cars like F1 have wide tyres so that they can get reasonable life out of them and also so that the heat generated during acceleration, cornering and braking can be extracted/;spread over a larger surface. The same amount of heat is generated whether the tyre is wide or narrow, but if there is more tyre, there is better air cooling and less sudden heat build-up during say a session of hard braking.

This does not translate to your 1962 Raleigh, even though you clearly have strong legs and develop enormous power - almost as much as me.

Yet, width does affect bicycle tyres too. Firstly, a wider tyre has less rolling resistance than a narrow one. The biggest reason, I think, is because the rubber deforms less and has less energy losses (hysterisis) when the tyre is wider. But don't think you can go on making it wider and wider. The sweet spot is probably around 28mm if you stick to a thin, non-armoured, non-armadillo type tyre. Puncture protection just adds thickness which adds hystererisis.

The second reason I think a wider tyre is slightly better is because it may grip better under certain conditions. Note that I'm not saying that there is a difference in the total amount of friction available in a narrow or wider tyre of the same compound and structure. Friction - therefore cornering ability or stopping distance remains exactly the same for wide and narrow. But, if you have a contact patch of 200mm^2 on your 28mm (wide) tyre and a contact patch of 150mm^2 on your 20mm wide tyre and you corner over a tiny slick of oil of 100mm^2, you will have 100mm^2 in reserve on the large tyre and just 50mm^2 on the narrow tyre. Should the 50mm^2 thus just not be enough to keep traction, you will slide on the narrow tyre but not the wider tyre.

But have a careful look at the scenario. It is pretty unlikely and probably far-fetched. Also note that the relationship between tyre width and contact patch size is not linear with the increase in tyre width. A 40mm tyre doesn't have a contact patch twice the size of a 20mm tyre. The increase is quite a bit less than doubling. There's a nice graph to demonstrate this in the article that Colin J linked to earlier on in this post.

You may or may not be better off sticking to your Conti's. The wider tyre will NOT give you better traction unless the road is softer than the tyre. That's not the case in city commuting. Wider tyres give you benefits such as pinch-protection and comfort, which narrow ones don't.

I would like to hear what others, as well as @PhilDawson8270 thinks of my "traction in reserve theory" for wider tyres.


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## Johnno260 (4 Nov 2016)

Yellow Saddle said:


> Perhaps you missed the discussion about how you cannot skid the front wheel on good road surfaces by braking hard.
> 
> Read through here and perhaps reconsider your stance.
> 
> https://www.cyclechat.net/threads/braking-hard-with-rear-brake.182211/post-3755598



where in the UK can I find this fabled good road surface? :-)


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## mjr (4 Nov 2016)

Yellow Saddle said:


> I would like to hear what others, as well as @PhilDawson8270 thinks of my "traction in reserve theory" for wider tyres.


I agree with @Johnno260 - many arguments are far too reliant on good road surfaces which seem to exist less and less with government cutbacks and 85% of what highway maintenance budget remains typically spent on A and B roads which are the least fun for cycling. This means that even in urban areas, loads of streets are thick in fallen leaf mulch until traffic has mashed it enough for it to wash away.

I think wider tyres give riders much more chance of part of the contact patch being on a bit of road which isn't totally covered in winter shoot and thereby giving enough grip. I feel 32mm may be the sweet spot for flexible tyres (including kevlar-lined) and 37mm for modern armoured ones.


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## Yellow Saddle (4 Nov 2016)

mjr said:


> I agree with @Johnno260 - many arguments are far too reliant on good road surfaces which seem to exist less and less with government cutbacks and 85% of what highway maintenance budget remains typically spent on A and B roads which are the least fun for cycling. This means that even in urban areas, loads of streets are thick in fallen leaf mulch until traffic has mashed it enough for it to wash away.
> 
> I think wider tyres give riders much more chance of part of the contact patch being on a bit of road which isn't totally covered in winter shoot and thereby giving enough grip. I feel 32mm may be the sweet spot for flexible tyres (including kevlar-lined) and 37mm for modern armoured ones.


Forget about identifying a road surface as good or bad - even though it was I who introduced the word good. I now regret it.
Think instead of the rule of thumb posted above.

Is the road harder than the tyre? If yes, ride slicks. If no, fit tread.

And a special case rule of thumb for the leaves scenario. Will your tread punch through the soft leaves to make contact with something harder underneat it? If no, ride slicks. If yes, fit such tyres if you can find them.

Guys, please stop whining about the quality of British roads. They are good. If you disagree, go have a holiday in a third world country. Ride a bike there if you dare.


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## ianrauk (4 Nov 2016)

Yellow Saddle said:


> please stop whining about the quality of British roads. They are good



And compared to roads in Europe, the roads in the UK are a disgrace.


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## Yellow Saddle (4 Nov 2016)

ianrauk said:


> And compared to roads in Europe, the roads in the UK are a disgrace.



Book a holiday in beautiful Costa Rica.


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## ianrauk (4 Nov 2016)

Yellow Saddle said:


> Book a holiday in beautiful Costa Rica.




No thanks.


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## EasyPeez (4 Nov 2016)

Yellow Saddle said:


> But, if you have a contact patch of 200mm^2 on your 28mm (wide) tyre and a contact patch of 150mm^2 on your 20mm wide tyre and you corner over a tiny slick of oil of 100mm^2, you will have 100mm^2 in reserve on the large tyre and just 50mm^2 on the narrow tyre. Should the 50mm^2 thus just not be enough to keep traction, you will slide on the narrow tyre but not the wider tyre.
> 
> But have a careful look at the scenario. It is pretty unlikely and probably far-fetched.



Thanks, this is helpful and insightful, as was the rest of your post. In relation to the extracted section, and recognising that the specific example scenario is unlikely, do the same principles not also apply to the much more likely scenario of cornering on a wet road surface? You'll have to forgive my scientific naivety here, but what I'm getting at is, isn't there a theoretically definable (assuming all variables of speed, rider weight etc were factored in) breaking point at which a cornering tyre will slip on a wet road? And wouldn't one of the affecting variables in this equation be size of contact patch? Ergo a greater contact patch on a wider tyre would mean the 'breaking point' at which the tyre lost traction would be less easily achieved? This may be nonsense, I'm just trying to better understand in layman's terms how this works.



Yellow Saddle said:


> The wider tyre will NOT give you better traction


Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not, then doesn't the fact that a wider tyre can be effectively run at 10-15psi lower than the narrower tyre mean that actually it could give better traction?


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## col.kurtz (4 Nov 2016)

Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not said:


> I was thinking the same thing, a lower pressure should equal a greater contact patch with the road, giving you more grip. The trade off I suppose is less responsive turn in?.


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## Johnno260 (4 Nov 2016)

I was being sarcastic, EU roads in the most part seem better than ours.

In general I think our roads are in the worst state I can remember, they should be in a better state than they're currently (in my opinion)

Potholes this year have cost me a set of bike wheels, and two alloy car wheels, in all circumstances I couldn't avoid the hole without causing a bigger accident, so from my point of view the roads are in a sorry state.


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## S-Express (4 Nov 2016)

ianrauk said:


> And compared to roads in Europe, the roads in the UK are a disgrace.



There are good roads and bad roads in every country, just like there are here. Except Malta - where the roads are universally terrible.


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## Yellow Saddle (4 Nov 2016)

User said:


> Wouldn't it be more positive to aim for good cycling surfaces for all, not justify poor ones because other people have worse.


Yes, Adrian, obviously it would. However, each time there is a broken spoke reported, it was because of the poor state of the roads. The two are not related. Each time someone gets a puncture, it is blamed on the poor states of the road. It isn't. Pinch flats excluded.
My remark about third world countries with bad roads was just to attempt to get some perspective.
However, I bet that many complaints here about a pothole is just that a complaint. Very few people report them. Our council has fixed every single pothole I reported within days. I catch people out when they complain and said the council did nothing. I ask them for the complaint reference number so I can follow up. My offer is not taken up.
I sense a lot of whining about things but not a lot of participation and understanding. Do you know anyone who has ever attended a council budget meeting in order to get an understanding of the finances and priorities of the budget?


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## Johnno260 (4 Nov 2016)

This year I gave up reporting as they had been reported and had cones/spray paint around them but not much was done for weeks.

Also I gave up trying to claim back on damages as my first attempts were so utterly stressful I couldn't face it, Kent and E.Sussex councils seems to make things hard so you give up.

I have attended my Parish Councils meetings, they're funny to be honest, the week after getting approval for a mobile phone mast on Parish land they spent a chunk of the money from the mast on giving the clerk who was the chairmans wife a pay rise! I sorta gave up on local government after that!


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## raleighnut (4 Nov 2016)

EasyPeez said:


> Thanks, this is helpful and insightful, as was the rest of your post. In relation to the extracted section, and recognising that the specific example scenario is unlikely, do the same principles not also apply to the much more likely scenario of cornering on a wet road surface? You'll have to forgive my scientific naivety here, but what I'm getting at is, isn't there a theoretically definable (assuming all variables of speed, rider weight etc were factored in) breaking point at which a cornering tyre will slip on a wet road? And wouldn't one of the affecting variables in this equation be size of contact patch? Ergo a greater contact patch on a wider tyre would mean the 'breaking point' at which the tyre lost traction would be less easily achieved? This may be nonsense, I'm just trying to better understand in layman's terms how this works.
> 
> 
> Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not, then doesn't the fact that a wider tyre can be effectively run at 10-15psi lower than the narrower tyre mean that actually it could give better traction?


IMO the thing is once you have lost traction on a wet road you're very unlikely to get it back.


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## EasyPeez (4 Nov 2016)

raleighnut said:


> IMO the thing is once you have lost traction on a wet road you're very unlikely to get it back.


I agree but I'm not sure how your point relates to my questions? Sorry if I'm being dim!


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## Yellow Saddle (4 Nov 2016)

EasyPeez said:


> Thanks, this is helpful and insightful, as was the rest of your post. In relation to the extracted section, and recognising that the specific example scenario is unlikely, do the same principles not also apply to the much more likely scenario of cornering on a wet road surface? You'll have to forgive my scientific naivety here, but what I'm getting at is, isn't there a theoretically definable (assuming all variables of speed, rider weight etc were factored in) breaking point at which a cornering tyre will slip on a wet road? And wouldn't one of the affecting variables in this equation be size of contact patch? Ergo a greater contact patch on a wider tyre would mean the 'breaking point' at which the tyre lost traction would be less easily achieved? This may be nonsense, I'm just trying to better understand in layman's terms how this works.


No.
Go and have a look at a few short videos on Youtube on friction for high school and university students. It is actually quite fascinating. Friction is NOT dependent on surface area so a bigger contact patch will not move the breaking point. This breaking point is where static friction becomes kinetic friction. It is not affected by surface area because if you use a smaller area (contact patch) under the same object, the pressure increases. As the pressure increases, so the friction increases. It is an almost linear relationship. That is the fundamental principle of friction. My example above was a very special case. What I did by greasing/oiling a piece of the contact patch was to decrease the effective size of the contact patch without increasing the area. A kind of cheating if you like. My explanation is wonky, come back to me if you don't get it. I'll try and think of a better analogy.
[/QUOTE]
Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not, then doesn't the fact that a wider tyre can be effectively run at 10-15psi lower than the narrower tyre mean that actually it could give better traction?[/QUOTE]

I assume you mean tyre pressure, not downforce?

Lets start with the ideal situation - tarmac. Lower internal tyre pressure will increase the size of the contact patch but decrease the pressure between rubber and road and cancel out the effect of larger contact patch - as per above. The rule holds: friction is not dependent on area.

The non-ideal situation number 1) is for instance where a tyre has to grip on soft turf. Here the surface is softer than the tyre and the tyre knobblies penetrates the turf to find footing deeper inside and then relies on the strength of the turf for traction. The stronger the turf, the better the traction. If the turf is very strong, only one knobbly needs to penetrate and traction is upheld. If the turf is loose and weak, more knobblies will improve traction because there are more "spikes" in the ground, if you like. Now, if softer tyre pressure allows more knobblies to penetrate, then lower tyre pressure will increase traction. If softer tyres don't make a difference to the foothold of the knobblies in the turn, then softer tyres are futile.
Scenario 2: The tyre has to find traction on gravel strewn on hard tarmac. We know rubber will grip the gravel but as you apply brakes, the gravel will roll away from under the tyre and you lose traction. If your knobbly can straddle gravel and find contact with the tarmac underneath, then it has benefits. If the knobbly cannot straddle the gravel, then it doesn't have a benefit and the tyre may as well be slick. Now, if a different tyre pressure gives the knobblies a better chance of straddling/penetrating between the gravel, then it is good, otherwise not.
Finally, on rough road such as road with large stone chips or as MTBers call them, marbles, a hard tyre bounces so much that it is more in the air than on the road. Reducing the pressure will keep better contact and hurt your beehind less. 

Chemically the two types of traction I've described here - rubber on hard tarmac and, rubber on soft surfaces, are completely different. The former invokes Van der Waal's weak force, the latter the shear strength of the substrate.

I don't think there is a blanket rule that softer tyres offer more traction than hard ones. This doesn't mean that you won't find applications where softer tyres work better - dragster racing for instance, but that is because a bunch of factors come together to create a sweet spot in the soft raange.


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## MiK1138 (4 Nov 2016)

Phew! first of all I hope Roosters bruises are healing nicely, second I am still confused on whether to replace my Nobbly MTB tryes with a more Slick tyre for Winter commuting in a urban area


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## Yellow Saddle (4 Nov 2016)

Johnno260 said:


> This year I gave up reporting as they had been reported and had cones/spray paint around them but not much was done for weeks.



Well, your council acknowledged the reporting of the hole, agreed that it is a safety issue and attempted to make it safer with the resources at hand. Resources are not unlimited. You probably cannot afford to live in a council area where they have 25 workers permanently on 24-hour standby with all the equipment warmed up and read to roll at the first report of a pothole. Or if you could find such an council at an affordable rate, you would probably not like the fact that there are no street lights, irregular bin collections and no social services.

Councils are not perfect and our roads are not perfect. Therefore it helps to understand priorities by attending meetings and contributing. Obviously squandering should not be tolerated, but keeping your finger on the pulse should keep that at a minimum.


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## Yellow Saddle (4 Nov 2016)

MiK1138 said:


> Phew! first of all I hope Roosters bruises are healing nicely, second I am still confused on whether to replace my Nobbly MTB tryes with a more Slick tyre for Winter commuting in a urban area


Slick.


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## mjr (4 Nov 2016)

Yellow Saddle said:


> However, I bet that many complaints here about a pothole is just that a complaint. Very few people report them. Our council has fixed every single pothole I reported within days. I catch people out when they complain and said the council did nothing. I ask them for the complaint reference number so I can follow up. My offer is not taken up.


I report them - certainly more than I complain in public about them. The council responses to them the last few years ranges between canned responses (most of the time) through to silence, which was once followed by an admission of complete inability to find a 3m x 1m crater on the inside of a sharp bend on National Route 11!



Yellow Saddle said:


> I sense a lot of whining about things but not a lot of participation and understanding. Do you know anyone who has ever attended a council budget meeting in order to get an understanding of the finances and priorities of the budget?


 but what's the point of going to the meeting, really? Nothing much interesting happens at most council budget meetings. It's all decided by the cabinet party long before that and then their ballast just waves it through. Sometimes opposition parties might make a few grandstanding amendment proposals but it's usually democracy theatre by that point.

The time to get involved is in the budget consultations which are starting in most places about now: visit your local county or unitary council website, look for consultations and say that you want 10% of the transport budget allocated to cycle routes including maintenance of roads that are key cycle routes. Go speak to your county or unitary councillor along similar lines.



Johnno260 said:


> I have attended my Parish Councils meetings, they're funny to be honest, the week after getting approval for a mobile phone mast on Parish land they spent a chunk of the money from the mast on giving the clerk who was the chairmans wife a pay rise! I sorta gave up on local government after that!


I'm pretty sure that if the chairman didn't declare a conflict of interest and excuse themselves, they should have been punished IMO.

Parish councils vary wildly and sadly the Vicar of Dibley wasn't as fictional as I might like, but they rarely have anything to do with cycling support beyond a few off-road routes and parking stands. District/borough/county councils tend to be a bit better-behaved, but local politicians are still mostly local people and some may be nobbers.


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## mjr (4 Nov 2016)

Yellow Saddle said:


> You probably cannot afford to live in a council area where they have 25 workers permanently on 24-hour standby with all the equipment warmed up and read to roll at the first report of a pothole.


Maybe not to that extent, but I'd happily pay a bit more council tax if some of it went to better cycle route repairs, but apparently "localism" doesn't extend to allowing local government to increase taxes more than Whitehall permits without holding a punitively-expensive referendum stacked against them.


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## EasyPeez (4 Nov 2016)

Yellow Saddle said:


> No.
> Go and have a look at a few short videos on Youtube on friction for high school and university students. It is actually quite fascinating. Friction is NOT dependent on surface area so a bigger contact patch will not move the breaking point. This breaking point is where static friction becomes kinetic friction. It is not affected by surface area because if you use a smaller area (contact patch) under the same object, the pressure increases. As the pressure increases, so the friction increases. It is an almost linear relationship. That is the fundamental principle of friction. My example above was a very special case. What I did by greasing/oiling a piece of the contact patch was to decrease the effective size of the contact patch without increasing the area. A kind of cheating if you like. My explanation is wonky, come back to me if you don't get it. I'll try and think of a better analogy.



Again, thanks for taking the time to offer such a thorough explanation.

In relation to the former, I understand what you are saying and no further analogy is needed. I had no idea of the linear r/ship between contact area and pressure when it comes to friction, so now I get why my ostensibly common-sense hypothesis becomes bunkem in the face of actual science!

And in relation to the latter, I can see how the same principles hold. I am only really interested in the tarmac riding as I already understood the basic gist of how reducing pressure can increase friction on rougher/softer terrains and ride those much more rarely (and on knobblies) anyway.

All that said, and while I don't doubt your explanation in the slightest and feel I have learned plenty, my instincts still tell me that a 35mm semi-slick tyre run at 75psi will hold onto a wet corner better than a 28mm slick at 95psi! I think we need to find a willing volunteer with a Gopro and a wet road to settle this once and for all in my mind....


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## Alan O (4 Nov 2016)

Yellow Saddle said:


> Guys, please stop whining about the quality of British roads. They are good. If you disagree, go have a holiday in a third world country. Ride a bike there if you dare.


http://www.bbc.co.uk/news/blogs-trending-37485461

Alan


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## Yellow Saddle (4 Nov 2016)

EasyPeez said:


> All that said, and while I don't doubt your explanation in the slightest and feel I have learned plenty, my instincts still tell me that a 35mm semi-slick tyre run at 75psi will hold onto a wet corner better than a 28mm slick at 95psi! I think we need to find a willing volunteer with a Gopro and a wet road to settle this once and for all in my mind....



Instinct is hard to overcome. That's why quantum mechanics is so daunting... as well as stereotyping and a bunch of other social evils.


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## Ajax Bay (4 Nov 2016)

EasyPeez said:


> my instincts still tell me that a 35mm semi-slick tyre run at 75psi will hold onto a wet corner better than a 28mm slick at 95psi!


If we're going to find someone to do that test, to take the same weight, if the 28's at 95psi, the 35 should be at 63psi ish.


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## Yellow Saddle (4 Nov 2016)

Alan O said:


> http://www.bbc.co.uk/news/blogs-trending-37485461
> 
> Alan


http://www.news24.com/SouthAfrica/News/Officials-act-after-woman-takes-bath-in-pothole-20140107


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## Ajax Bay (4 Nov 2016)

A little bird tells me that very slightly damp surface is better than a dry one, for grip! (Unfortunately it's not just a little damp outside; it's wet, and I'm wimping out of my ride this lunchtime.)


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## ColinJ (4 Nov 2016)

User said:


> There is a valid issue here. A rider who is in control, and feels it, will be smoother than one who is nervous about loosing grip. It is probable that the more nervous ride is more likely to contribute to their own downfall.


OTOH, someone who puts excessive trust in a tyre's tread/width/pressure/compound's ability to cope with dicey conditions is more likely to come a cropper than someone who doesn't!


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## EasyPeez (4 Nov 2016)

Ajax Bay said:


> If we're going to find someone to do that test, to take the same weight, if the 28's at 95psi, the 35 should be at 63psi ish.


Sounds like we have a volunteer to me...


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