More or less skid patches for winter tires?

Question

Update: this question is NOT about how to calculate the # of skid patches. I've always used http://www.bikecalc.com/skid_patch_calculator for that and the math is sound.

So, I'm already thinking ahead to next winter to see what I could do better with my fixed gear winter commuter. I'm running a pretty conservative gearing with a deliberately odd-numbered cog (21T I believe) to spread the skid patches all over my rear tire (update: I'm running 44x21 so 21 skid patches, which is a lot). This winter I tried the Schwalbe Marathons and was pleased generally, but after only two months of daily riding, the rear tire looks like the tonsure on a monk's head: completely bald in the middle and treads on both sides.

Why? Because I have SO MANY skid patches that it's a pretty uniform wear. And I hear that the Schwalbes use a pretty soft compound so they wear fast.

So, I'm wondering, what if I switched to an even gearing with **LESS* skid patches? Like a 45x20 for 8 skid patches. Obviously, some parts of the tire would wear more... but others would keep their tread... Has anyone tried this and is it a horrible idea? Or is there some merit? Again, I'm focusing on WINTER riding where I might want to preserve a little tread for grip.

And yes I run a front brake.

Answer 1

Less skid spots is going to mean uneven wear. Every time you try to stop, you'll be skidding on the more worn out parts. You're better off having even wear and replacing your tire as needed, less skid spots pretty much guarantees you'll need to replace your tires more often, with more chance of blowouts.

Good tread is most important on your front tire, especially for winter riding, so make sure that one is not super worn.

If you have a low number of skid spots, you can try and loosen your chain and rotate your wheel slightly to change where the skid spots hit as kibbee said. It can be hard to remember to do that though. Though, It will make the wear more even, causing the same issue you're already concerned about.

If your tire is bald on the center and tread on the sides, you may want to lower the pressure somewhat in your tires to widen the contact patch and allow more of the tread to contact the ground, providing a bit more stopping power and making for more even wear.

Barring all that, you may just want to switch up your tire to something that wears differently. I've had good luck with thick slicks and panaracer ribmo tires. Both have a bit of extra tread in the center and wear down to a flat profile over time.

Answer 2

To spread skid patches around the tire, you need to have chainring and cog that have mutually prime tooth counts, i.e. no common divisors. With a common 42 tooth chain ring, 21 is the worst possible choice because it produces a straight 2:1 ratio. If this did no seem to make sense, search for "skid patch calculator" to find interactive visualizations.

If you really want to avoid excessive tire wear at the cost of some style points, a front brake is great. Also, the current version of Schwalbe Marathons doesn't seem to wear that well.

Edit: After writing the answer, the question has changed. Having less skid patches is a good idea, if your aim is to wear the tire to cords faster. It will not help with braking because the tire has skid patch facing ground when you brake. It will also not help much with lateral grip, because the smooth patches will be even smoother.