Directional tread pattern

[zacklaws]

The simple rules of directional tyres are, on a road bike, if you have directional tyres the arrow must point in the direction the tyre is going to rotate for the rear, front tyre the directional arrow can point either with the rotation or against, in wet or icy conditions though reverse it as you get slightly better grip when it comes to braking and not so likley to slip out from under you, but could lock up easier and slide out so its a gamble what you do, MTBs rear as a road bike and front tyre arrow should be pointing in the opposite direction of rotation, so your rear tyre grips better to propel you forward from the pedaling action but with your front reversed you get a better braking effect on rough surfaces. If it is a MTB and the emphasis is on fast downhill, fit both tyres in reverse as power transfer is not a priority but you can obtain maximum braking effect from your tyres.

Schwalbe MTB tyres can come with with the tyre marked up with two arrows, one arrow relates to fitting on the front and the other for the rear

 

[Ajax Bay]

simple rules of directional tyres are, on a road bike, if you have directional tyres the arrow must point in the direction the tyre is going to rotate for the rear, front tyre the directional arrow can point either with the rotation or against, in wet or icy conditions though reverse it as you get slightly better grip when it comes to braking and not so likley to slip out from under you,

How does the design of the tyre (road tyres, on road) result in any difference, whichever way the tyre is fitted? Tread makes no difference to grip on asphalt so is it in its construction (ie casing) that you suggesting the direction of mounting of the tyre has a differential effect on its performance (drive grip or under braking)?

The casing is perfectly symmetrical. There is no difference between right way and also right way round.

I assert:

Given the forces involved it is unlikely that there will be any performance merit or loss whichever way round tyres are mounted, irrespective of 'drive arrow' markings. The latter have been put there, much as the tread has, to meet customers' expectations, and possibly for aesthetic reasons (to avoid the 'look he's put the tyres on back-to-front' comments from the incognoscenti).

 

[PhilDawson8270]

Slicks are better in the wet then tyres with tread as there is more contact with the road.

But friction is not related to surface area. I questioned this with Schwalbe, and they refuse to answer the question relating to their misleading statements.

 

[Yellow Saddle]

But friction is not related to surface area. I questioned this with Schwalbe, and they refuse to answer the question relating to their misleading statements.

Ianruak's statement is true, but not the rationale. And by tread in this instance I am talking about sizeable discreet blocks of thread, not little file thread patterns which are essentially slicks with a pattern to satisfy customer perception.

 

[Yellow Saddle]

The simple rules of directional tyres are, on a road bike, if you have directional tyres the arrow must point in the direction the tyre is going to rotate for the rear, front tyre the directional arrow can point either with the rotation or against, in wet or icy conditions though reverse it as you get slightly better grip when it comes to braking and not so likley to slip out from under you, but could lock up easier and slide out so its a gamble what you do, MTBs rear as a road bike and front tyre arrow should be pointing in the opposite direction of rotation, so your rear tyre grips better to propel you forward from the pedaling action but with your front reversed you get a better braking effect on rough surfaces. If it is a MTB and the emphasis is on fast downhill, fit both tyres in reverse as power transfer is not a priority but you can obtain maximum braking effect from your tyres.

Schwalbe MTB tyres can come with with the tyre marked up with two arrows, one arrow relates to fitting on the front and the other for the rear

This is completely out of kilter with science even though it is peppered with scientific sounding words like "propel forward" and "pedaling action."

 

[PhilDawson8270]

Ianruak's statement is true, but not the rationale. And by tread in this instance I am talking about sizeable discreet blocks of thread, not little file thread patterns which are essentially slicks with a pattern to satisfy customer perception.

I think I missed your post, but are you referring to the movement of discreet blocks that therefore increase the tyre temperature. That in turn increases the friction in the cold/wet?

 

[Yellow Saddle]

I think I missed your post, but are you referring to the movement of discreet blocks that therefore increase the tyre temperature. That in turn increases the friction in the cold/wet?

No. Discreet blocks increase tyre squirm which increases rolling resistance. This wasn't discussed here but I want to put that down as a disadvantage. Discreet blocks/fingers flex with the vector of the turn and tend to "walk" you off course. It is a bit like understeer in a car. In the wet, the curled-over edge introduces water between rubber and road, reducing friction. The examples are extreme, but the concept can be scaled down accordingly, up to a point.

My tyres never smoke when I pull off or corner. It is bad form to do so and it scares old ladies and their Chihuahuas.

 

[winjim]

My snow tyres have a V shaped tread which I presume is for dispersing loose snow and slush, rather like a tractor tyre. I have fitted them the correct way round.

 

[zacklaws]

How does the design of the tyre (road tyres, on road) result in any difference, whichever way the tyre is fitted? Tread makes no difference to grip on asphalt so is it in its construction (ie casing) that you suggesting the direction of mounting of the tyre has a differential effect on its performance (drive grip or under braking)?
:

Most road tyre are slicks, but some have tread, ie winter tyres for that extra grip, Bontrager All weather, for example. By fitting one in reverse on front, the braking action will bite into the road surface as opposed to skidding across it, no traction can be applied to a front, so fit it in reverse to aid in braking, likewise when its fitted in the correct rotational direction at the back, when your going uphill for example on a wet road the tread will grip as opposed to wheel spinning which you get with slicks and I definitly do when going up a steep hill in winter when its wet. I have almost fell off some times when traction is lost on steep hills and only saved myself by unclipping fast and get a foot down. In winter I now run marathon plus as a training tyre on my winter trainer, a CX bike, on the road and when going uphill when its wet, the grip is so positive that I can almost stop due to the steepness, put some pressure on the pedals and instead of a spinning the rear wheel, I will slowly move forward in responce to the pressure as the tyre grips.

 

[fossyant]

If it is a MTB and the emphasis is on fast downhill, fit both tyres in reverse as power transfer is not a priority but you can obtain maximum braking effect from your tyres.

Schwalbe MTB tyres can come with with the tyre marked up with two arrows, one arrow relates to fitting on the front and the other for the rear

Don't flip the arrows on the front - the pattern on the front will be already for braking on an MTB.

 

[Ajax Bay]

On a road surface, wet or dry, you will brake and grip in corners with more effectiveness/assurance on slicks (ie a tyre with no tread pattern) of the same rubber compound. You will also get more traction up hills (a less limiting condition than braking imo). Where is @Yellow Saddle when he's needed? @zacklaws you are getting "grip . . so positive that. . . instead of a spinning the rear wheel, I will slowly move forward" on your M+s. I have had an M+ on the rear and it gives excellent grip (but it's hideously heavy (750g+ in a 28-622)). So does my current GP4S (for example) - give excellent grip that is. If you had a(nother) decent slick tyre on the back instead of your M+ (ceteris paribus) you'd get equal grip (depends not on tread but rubber compound suitability for that surface).

 

[Yellow Saddle]

Most road tyre are slicks, but some have tread, ie winter tyres for that extra grip, Bontrager All weather, for example. By fitting one in reverse on front, the braking action will bite into the road surface as opposed to skidding across it, no traction can be applied to a front, so fit it in reverse to aid in braking, likewise when its fitted in the correct rotational direction at the back, when your going uphill for example on a wet road the tread will grip as opposed to wheel spinning which you get with slicks and I definitly do when going up a steep hill in winter when its wet. I have almost fell off some times when traction is lost on steep hills and only saved myself by unclipping fast and get a foot down. In winter I now run marathon plus as a training tyre on my winter trainer, a CX bike, on the road and when going uphill when its wet, the grip is so positive that I can almost stop due to the steepness, put some pressure on the pedals and instead of a spinning the rear wheel, I will slowly move forward in responce to the pressure as the tyre grips.

Tyre "grip" does not work like you think and extrapolating tractor tyre patterns to bicycle tyres is wishful thinking. The concept does not scale down.

Tyre grip on surfaces where the softest of the two surfaces is the tyre, is entirely dependent on the type of rubber and specifically, its co-efficient of friction and, the downforce or weight on the tyre. Obviously the road surface plays a role but we can't change that. The grip has nothing to do with the thread or thread pattern at all. Thread and thread patterns and directional arrows on bicycles are invented purely for marketing reasons. The casing is perfectly omnidirectional since the cords are criss-crossed at an angle - 37.5 degrees, that sees to it that the tyre does not become shorter or fatter depending on tyre pressure. You can see this angle and exact design on clear high-pressure hose where you can see the cords inside.

The notion of "bite into the road surface" is just that, a notion but not reality. Slicks give better grip than tyres with real thread (file tread is just optical illusion slicks) because of reasons I've mentioned previously. I have explained why it pays to sometimes give heed to directional arrows. This is valid for one type of tyre only, the Maxxis (cant remember the model name now) with a central ridge of rectangular blocks. These blocks are all chamfered at the leading edge but not at the trailing edge. Running them the wrong way around is noisy for a while.

Where the tyre is harder than the riding surface, i.e. putty-density mud or sand on top of hardpack, the tread is useful. Here it penetrates softer top layer and settles on harder substrate underneath. Where the top substrate is slushy, the knobblies do nothing. Here you have to run a narrower tyre that can hopefully sink in to a harder substrate underneath. Running tyres with substantial finger-like tread on snow will give you better grip than slicks. This is because the finger knobblies will penetrate up to where the tyre casing contacts the snow and compact it around the knob and there will be grip. However, that is not the scenario we're talking about which is a thin layer of snow or worse, ice, on asphalt.

One analogy I can think of is running a kitchen grater over glass. No matter which way it points, the rasp still slide with the same ease over the glass. Make it run over wood and the story changes. Road bike tyres and much dry offroad riding all benefit from slicks.

 

[Citius]

the braking action will bite into the road surface

So, soft rubber 'biting' into hard tarmac. Let's just think about that for a while....

 

[Citius]

Good job these guys don't ride on the roads then...

 

[zacklaws]

Don't flip the arrows on the front - the pattern on the front will be already for braking on an MTB.

If you search on line. you will find many sites refering to flipping a front MTB tyre to improve braking, it is not just a theory I have dreamt up, for example:-

http://workingoncycles.blogspot.co.uk/2012/09/tyre-fitting-tread-direction-for-off.html

Note the bit where its mentioned how the Pro's have there front tyres flipped.

If you had a(nother) decent slick tyre on the back instead of your M+ (ceteris paribus) you'd get equal grip (depends not on tread but rubber compound suitability for that surface).

I used to ride Conto 4000GP S all year round, the grip going up wet very steep hills at times was next to useless with occasional wheel spins especcially if you hit a patch of mud or tried to speed up. I have even ripped grooves into the tyre from wheel spins on rough tarmac. Marathon Plus maybe heavy, but this time of year, its not all about speed and how light your bike is, resistance training comes to mind for example, along with doing the best to avoid having to repair punctures in freezing cold conditions.