Big wide slicks in the autumn and winter

[alexnharvey]

Is a fat slick tyre (say >32mm) more at risk of sliding during our winter UK road conditions than the narrower tyres (23-28mm) preferred in the past?

[Brucey]

I think it might be. The rationale is that when the road surface is textured normally and is merely wet (with clean water) it may not make much difference, but when the surface is smooth and/or covered in slimy crud, a tyre that is skinny at higher pressure and/or has tread may cut through the soft stuff and find grip where a wider tyre might just tend to float over the surface.

A good example of this is when you ride in freshly fallen wet snow; you only start sliding around on it once the tyres don't push their way through it to the road surface, and this happens more easily with wider tyres that have little or no tread.

cheers

[bgnukem]

I'd agree, wider slicks run at lower pressures than a narrower treaded tyre will produce larger contact patches at the road surface, but lower contact pressures (assuming the weight of bike and rider is the same in both cases), since Force = Pressure x Area. This makes it less likely that the tyre will 'push through' slippery substances on the road surface, e.g. mud, slush or leaves, to make contact with the tarmac.

Tread effectively reduces the contact areas between the tyre and the road and thus increases the contact pressure, so should help adhesion. Taken to the extremes of knobblies, though, I find this can make the handling skittish, as the knobs flex and deform when cornering, not to mention inefficient w.r.t. rolling resistance.

I was wondering the other day if any manufacturers make 'cold weather tyres' for bikes, similar to those for cars, made from rubber compounds designed to grip better at low temperatures. ISTR the Conti GP 4 season was maybe an example?

[rotavator]

I was wondering the other day if any manufacturers make 'cold weather tyres' for bikes, similar to those for cars, made from rubber compounds designed to grip better at low temperatures.

Conti top contact winter II premium (snappy name ) are a non-studded winter tyre and they are pricey

[julianm]

Specialised used to make a tyre with a flat raised centre section which was had no tread, the shoulders were a bit herringbone I think. The idea was that the harder (I think) raised bit wore well & the shoulder helped on corners.
It didn't work out for me on a wet roundabout in Castleford when the front wheel lost all traction, shot sideways & I hit the deck.
Once I was on the floor I could smell the diesel from a spill from a fuel tank, so maybe any tyre would have done the same. I think a bit of tread might help in typical winter riding conditions.

[mig]

I was wondering the other day if any manufacturers make 'cold weather tyres' for bikes, similar to those for cars, made from rubber compounds designed to grip better at low temperatures.

Conti top contact winter II premium (snappy name ) are a non-studded winter tyre and they are pricey

they are good though. used them for a few years now but not 37c, more like 32c.

maybe nokian do a similar tyre too. they do plenty of spiked tyres.

[PH]

I don't know, it's just guessing. The three times I've come down on tarmac, hard enough to remember, have been on three very different bikes with different tyre widths, gravel, ice and some other slippery substance probably diesel. It's possible that at least one of those might have been avoided by a different tyre, it's also possible that the tyre which saves you on one corner might be your downfall on the next (Literally). It's one of those questions where the answer can only be preceded by - all other factors being equal - and they rarely are.
One thing I do know is that it hurts and the older I get the longer it hurts for. I try not to ride if there's any chance of ice, I have a bike ready for if I do, complete with shiny studs, I'll be happy for them to stay that way.

[mattsccm]

I can't make up my mind. Theory goes with a narrow tyre cutting through and all that but on slippery surfaces I am not so sure as possibly a greater contact area could counter act that. My Land Rover grips better in deep snow with narrow very knobbly tyres but on pure ice or very hard packed snow the wider , less aggressive pattern works better.
I find that, on my bike, the greasy commutes see less wheel slip up a couple of wet, mucky, marginally tarmaced, but smooth, hills with wide (36mm) slicks than my summer 28mm tyres. Braking feels more secure although it is harder to prove as I am not going to push enough to find the failure point!

[Brucey]

FWIW ice (and snow once compressed past a certain point) is a special case; it is widely held (*) to be slippy because you get incipient melting under contact pressures. At very low temperatures, very low pressure tyres may not create enough pressure to cause incipient melting, so ice may not be slippy. However in the UK it is more likely that temperatures will be hovering just below zero and more or less any contact pressure will be enough to cause the ice to be very slippy indeed.

[edit; (*) more recently a new explanation has emerged; it turns out that the pressures required to form a stable liquid phase are incredibly high, beyond what is possible. The new explanation is that over a wide range of temperatures the surface of ice is covered in a layer of weakly bonded water molecules, and these give a low coefficient of sliding friction. Presumably this explains why the surface of ice can be polished even at low temperatures, too. Arguably the 'loose molecules' are not dissimilar to there being a one-molecule thick layer of liquid water on the surface of the ice.]

cheers

[Biospace]

There's no single right answer, unless considering one specific set of circumstances. Tyres at each extreme might work best in extreme conditions but be the worst choice inbetween. I think a traditionally treaded 26x1⅜ tyre would work as well as any in a variety of winter conditions, the softer the compound the better.

[bgnukem]

UK winters are a pain. it's rarely cold enough for long enough to be worth fitting my studded tyres, but there are still enough days where it's rained and then temperatures are low enough to have to worry about icy patches on the country lanes which are never gritted, while riding on main roads just means getting buzzed by impatient drivers....

[cycle tramp]

I was wondering the other day if any manufacturers make 'cold weather tyres' for bikes, similar to those for cars, made from rubber compounds designed to grip better at low temperatures. ISTR the Conti GP 4 season was maybe an example?

Rather than add to the pressures felt by the nhs by coming off my bike along a lane strewn with mud, wet leaves, and the manure from every known farm animal known to man...

....I decided to buy some new tyres...

Rated for all season use (although schwalbe recommend using studded tyres during icey conditions) they aren't as slow as they look