# Winter tyres



## Ming the Merciless (26 Jan 2020)

Just bought one in 40-406, winter compound and sipes just like car winter tyres, for front wheel of recumbent.

https://www.schwalbe.com/en/tour-reader/marathon-gt-365


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## voyager (26 Jan 2020)

Interesting write up . Keep us informed with a road test later.

Regards Emma


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## Yellow Saddle (26 Jan 2020)

YukonBoy said:


> * winter* compound and *sipes *just like car winter tyres,


I won't burst your bubble.


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## Ming the Merciless (26 Jan 2020)

Yellow Saddle said:


> I won't burst your bubble.



They work extremely well on cars better than chains. So go on then why no good for bikes?


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## Yellow Saddle (27 Jan 2020)

YukonBoy said:


> They work extremely well on cars better than chains. So go on then why no good for bikes?


Start with this thread from some years back.


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## Nigelnightmare (27 Jan 2020)

Same rolling resistance as Marathon Plus!
And they feel like you're riding through treacle.
GOOD LUCK.


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## Ming the Merciless (27 Jan 2020)

Nigelnightmare said:


> Same rolling resistance as Marathon Plus!
> And they feel like you're riding through treacle.
> GOOD LUCK.



better than being flat on your arse on a cold frosty day


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## Ming the Merciless (27 Jan 2020)

Yellow Saddle said:


> Start with this thread from some years back.



You seem to have missed a link whatever thread you want me to take a gander at.


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## Yellow Saddle (27 Jan 2020)

YukonBoy said:


> You seem to have missed a link whatever thread you want me to take a gander at.



Sorry. I think it was this thread. Alternatively, search for "smooth tyre" and "file pattern". That too should take you to past discussions.

https://www.cyclechat.net/threads/directional-tread-pattern.116590/page-2#post-4109284


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## Ming the Merciless (27 Jan 2020)

Yellow Saddle said:


> Sorry. I think it was this thread. Alternatively, search for "smooth tyre" and "file pattern". That too should take you to past discussions.
> 
> https://www.cyclechat.net/threads/directional-tread-pattern.116590/page-2#post-4109284



Ah you mis understand the siping here is not about water dispersal. It’s about improved grip on slippery surfaces such as frost, snow, ice.


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## Yellow Saddle (27 Jan 2020)

YukonBoy said:


> Ah you mis understand the siping here is not about water dispersal. It’s about improved grip on slippery surfaces such as frost, snow, ice.


No, it doesn't work like that. 
Let's look at your three scenarios.
1) Frost. This is small ice crystals formed from atmospheric water that condensed onto surfaces before freezing.. The crystals are weakly attached to whatever it has settled on. For a tyre to grip on frost, it has to disperse the frost and find traction underneath the frost. How do you propose this happens with those tyres? It can't cling to the frost, because the frost itself has no grip on whatever it has settled on.
2) Snow. Snow is powdery ice crystals and offers just about zero traction. In order to gain traction on snow you have to penetrate the snow and find footing underneath. How do those tyres facilitate that process?
3) Ice. Nothing grips on ice, that's why it is so slippery. You can have traction on ice, but then you need something that's harder than the ice that can penetrate the ice to a reasonable depth - like tyre studs or golf shoes. Do you really think a few grooves in rubber will do the trick? 

Traction is mysterious but it needn't be. Think through the scenarios and ignore marketing hype.


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## Ming the Merciless (28 Jan 2020)

Yellow Saddle said:


> No, it doesn't work like that.
> Let's look at your three scenarios.
> 1) Frost. This is small ice crystals formed from atmospheric water that condensed onto surfaces before freezing.. The crystals are weakly attached to whatever it has settled on. For a tyre to grip on frost, it has to disperse the frost and find traction underneath the frost. How do you propose this happens with those tyres? It can't cling to the frost, because the frost itself has no grip on whatever it has settled on.
> 2) Snow. Snow is powdery ice crystals and offers just about zero traction. In order to gain traction on snow you have to penetrate the snow and find footing underneath. How do those tyres facilitate that process?
> ...



Yes it does, it’s proven in practice rather than any theory you might have.

Suggest you read up on how it works especially around what happens on snow.


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## Pale Rider (28 Jan 2020)

YukonBoy said:


> Yes it does, it’s proven in practice rather than any theory you might have.
> 
> Suggest you read up on how it works especially around what happens on snow.



Winter compound tyres certainly work on cars.

A mate of mine has them.

His only gripe is sometimes he still can't get to where he's going because of drivers on ordinary tyres stuck in front of him.

Sheet/black ice may be the exception, but the amount of that is comparatively small.

Most adverse winter conditions are frost/sleet/snow that's thawed then frozen leading to the typical British winter sludgy mess on which winter tyres prosper.


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## Yellow Saddle (29 Jan 2020)

Winter tyres on cars certainly work...in the right conditions. However, that' doesn't mean a winter tyre "works" on bicycles.

The story is a complicated one, but I'll try and lay it out clearly.

First you have to understand that car and bicycle tyres are not in any way similar. I've already lined a thread that explains the reasons why. The primary take-away there is that tread on bicycle tyres intended for use on tarmac roads is unnecessary and counter productive. It is pure psychology.

Car tyres come in three seasonal categories namely:
a) Summer tyres (for very hot climates where the minimum temperature is very seldom below 7degrees C). These are not for the UK.
b) All-season tyres where the maximum temperatures are in the twenties and minimums in the minimums just below freezing. These can be used all year round in the UK.
c) Winter tyres where the minum temperatures can get way below zero. These have to be swapped out for all-season tyres in the summer.

The difference between a) and b) is purely rubber compound. Manufacturers may well adorn them with different patterns of tread but that's not what makes the difference. The difference is purely that the all-season tyre has a compound that doesn't harden as much when the temperature gets really low. This ensures that it still has reasonable grip when the temperature drops. The difference has nothing to do with the way it mechanically deals with snow or water or frost or whatever. It is purely softness.

Winter tyres, category c) above, are different. They have a still-softer compound that maintains grip in even lower temperatures but are also slightly narrower (for the same fit) and have different tread pattern that includes many smaller cuts. These cuts are not grooves but thin, narrow cuts which cannot transport water. These cuts, called sipes, are located inside blocks of thread which have wide grooves around them for transporting water. In other words, they look like summer tyres but have small cuts inside the tread blocks.
Transporting water is not their function. Their function is to squirm under pressure. Squirming does two things: It allows the tyre tread blocks to change shape and shed snow or mud (helped by rotational speed of the wheel) and, it creates extra friction inside the tyre (i.e. increases rolling resistance) so that the tyre can run warmer than other tyres. That's right, the tread design can determine the running temperature of the tyre. The thinking is that a warmer tyre is softer and offers more grip. This extra heat is accentuated under heavy braking or cornering because that's when the tyre squirms the most and needs grip the most.

*Let's get to grips with grip.*
Tyre grip can be classed into two categories.
a) The physical-chemical effect of Van der Waals forces.
b) Purely mechanical effect of tread pattern.

*Physical-Chemical Grip.* Passenger tyres rely 100% on this. This means that any grip is generated by small di-pole attractions between the molecules of the road and the molecules of the tyre. THERE IS NO MECHANICAL INTERLOCKING INVOLVED. Let me repeat that: There is no mechanical interlocking involved. In other words, the tread shape has nothing to do with this type of grip. There is no digging in, no hooking onto rough bits, no reliance on surface texture. All that's required is that the tyre molecules are squeezed up against the road surface molecules as closely as possible so that Van der Waal's can switch on. Wikipedia or your old chemical textbooks can do a better job at explaining Van der Waals weak forces than I can. Go read up on it. In a nutshell, it works like a very, very, very small magnetic force that only switches on on close (extremely close) proximity. That's why there's more grip when you push hard downwards on your cars or shoes. You are increasing the Van der Waal's. Van der Waal's does not, as you know by now, rely on shapes or blocks or penetration or roughness. You can demonstrate this for yourself by taking a pencil eraser and pulling it across your perfectly smooth bathroom mirror. If you push harder, the eraser is more difficult to drag along. If you push hard enough, Van der Waal's is so strong that it rips bits of plastic from the eraser. Try it. Please.
This is how a passenger car stays on the road - Meneer* Van der Waal keeps it on the road, allows it to accelerate, brake and corner.
Winter tyres have softer rubber that allows the tyres to make better contact with the road and switch on more of these tiny Van der Waal magnets. Why don't we use winter tyres all the time? Because they are too soft and perform poorly in comparison to other tyres. They only outperform other tyres when it is cold, at all other times they create longer braking distances. There is no advantage to using them in the UK because it simply isn't cold enough for All Season tyres to start performing worse than a Winter tyre would.
Van der Waal's forces cannot be measured using dimension and is expressed purely as a co-efficient, known as the co-efficient of friction. It is the "strength" of the friction, if you like. A hot, semi-molten dragster tyre has a co-efficient of friction of 2 and an ice skate on ice, something like 0.2 (these things can be looked up in tables).

B) *Mechanical effect of tread pattern.* This applies to surfaces which are softer than the tyre and we rely on the tyre to make an imprint in this surface so that it can compact the soft material and make it a bit "stronger" to offer a mechanical interlock between the tyre and the surface - typically compacted mud or sand or snow. Passenger cars don't rely on this mode of friction and SUVs/ATVs have tyres which do rely on this. They perform poorly on hard surfaces because the squirm and "walk" around corners causing understeer, poor braking, noise and high rolling resistance. If you've ever had the opportunity to fit a mountainbike with aggressive knobblies intended for mud, such as Michelin WildGrippers (aka WildSlippers) and taken a few turns on tarmac, you'll know what it feels like to have understeer on a bicycle on good surface. The weak little lugs bend and flex, causing very poor steering. However, in mud they work better than a smooth tyre intended for tarmac. I've explained the mechanism above, and further above explained why the flexible lugs shed compacted material stuck in the tyres. It is important that these tyres don't hold onto the mud or snow but start each revolution with a clean slate. Otherwise it is mud-on-mud and they can't dig in.

This type of lugged tyre cannot work on ice. That's because the ice is harder than the tyre. Lugged tyres rely on soft substrate so that it can make an impression, compact and take advantage of the little Lego-interface it has created. On ice, such as black ice or white ice or whatever colour solid, hard ice you'd like to throw at them, none of these two types of grip works. Ice has very little Van der Waal's attraction to other materials and thus has a low co-efficient of friction. It is no use trying to apply different types of rubber or different tread patterns to the problem, nothing will grip on ice, period.

There is a subset of the grip described in this section (mechanical interlocking) and that is tyres with metal studs. This is basically a way of making the tyre harder than the substrate. Sharp little studs penetrate the ice and creates grip that way.

*Back to bicycle winter tyres. *

A bicycle winter tyre (without studs) is a fallacy. It is a clever bit of psychology designed to make you buy special tyres that will solve a perceived condition.

a) Bicycle tyres don't need grooves to shed water.
b) Tread pattern doesn't matter unless we're talking deep, narrow flexible lugs that can penetrate the soft substrate.
c) Sipes don't matter because bicycle tyres don't generate enough heat to change compound hardness.
d) A very soft tyre designed for winter bicycle use could offer some extra grip on cold, hard, non-iced surfaces, but then it would have to be smooth and very soft because sipes would give you understeer as dangerous as ice itself.

I have no doubt that companies like Swalbe understand all this. After all, they employ engineers qualified in tribology, as well as polymer chemists. However, these Bicycle Winter Tyres were designed in the marketing boardroom, not the laboratory.


* _Meneer means Mister/Sir in Dutch. Van der Waal was a Dutchman._


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## Ming the Merciless (29 Jan 2020)

Nothing has grip on ice eh?


View: https://youtu.be/qrN8cPcLJNM


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## 8mph (29 Jan 2020)

Very wise - I've been off the bike for 8 days after taking a tumble on frost. Since then I've found out that knobbly tyres are no defence against frost and ice. It happens so fast, I don't remember losing balance, just one-moment riding, the next sliding down the tarmac with my head 6" off the road. It wasn't even very cold, the sun was shining, it must have been a patch of road where the sun hadn't reached by 11.30am.


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## Yellow Saddle (29 Jan 2020)

YukonBoy said:


> Nothing has grip on ice eh?
> 
> 
> View: https://youtu.be/qrN8cPcLJNM



Look, I can show you videos of David Copperfield making a Boeing disappear on stage or walking through glass, but it will not stand up to scientific scrutiny. 

Thousands, if not millions of people fall and injure themselves every single winter, from slipping on ice. If someone had a technology that could prevent that, it would be extremely valuable and would, by now, have been licensed by every single shoe company in the world. It hasn't. I'll draw my conclusions from that, you will obviously find another reason.

I cannot argue against someone who doesn't understand science. If you believe, you believe.

There is something else at play in that video, other than magic ice magnets.

However, the value and veracity of that demonstration is perhaps best reflected in this screen grab off that fantastic invention's YouTube page:

The date, views and comments say a lot. If you don't believe that, why not go and offer them a small bit of money to take their patent off their hands. It'll be worth a billion or more to you, for a very small investment.


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## Nigelnightmare (30 Jan 2020)

YukonBoy said:


> Nothing has grip on ice eh?
> 
> 
> View: https://youtu.be/qrN8cPcLJNM




Wow!
Just look at all those sipes.

Oh hang on a minute that was scratches on my safety classes
With good reading glasses on the diamond shaped bits look almost exactly like my Schwalbe Kojack "Slick tyres" tread.

I'd like to see that same experiment carried out after wearing those shoes for a week when they'll be covered in contaminants and be slightly worn.


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## viniga (30 Jan 2020)

FWIW I have used studded tyres in the winter in Scotland. These are excellent at crossing ice. (In fact it has allowed me to cycle quite happily across ice surfaces I couldn't walk on!) I have no idea if the rubber compound itself is different, softer in the cold etc... it might be... and they do have a deep tread and seem to perform reasonably well in snow. I am still v cautious in frost, snow or mud as I realise that the studs don't help there.


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