11-20-09 - Bike Tires

A lot of people believe that they should get bike tires with a bit of tread pattern, grooves or knobs or something for "good grip" or "water channels". This is a lot of crap that's gotten into people's heads from the car tire advertisements. See the experts : 1 , 2 , 3 on tire choice.

So now that you've read them you should be drinking the kool-aid that slick tires are the way to go because they maximize grip on pavement and will never hydroplane.

I don't think so. The truth is, grip on smooth pavement will never be a problem with bike tires. As Sheldon's chart shows, it's basically impossible for you to ride fast enough or corner hard enough to exceed the friction limit of a bike tire on pavement - even wet pavement. So why optimize for that? Slicks might give you optimum grip, but you already have plenty.

In reality, grip issues when biking will occur when your tires *aren't* in contact with pavement. I've had bad wipeouts due to gravel, sand, etc. In Seattle we also have the "steed" - the rotting leave gunk that's as slippery as a banana peel. When your tires are on steed you have no grip, and a bit of a knob to cut through that and get to actual pavement would be a huge boon. (it's called "steed" because rotting leaves are almost the most disgusting thing in the world, they're goopy and brown and smelly like a giant film of shit that gets on everything - second only to Paul Steed who is the most disgusting thing in the world).

I don't know what the best compromise is for a tire that can cut through some steed but still have good pavement grip. Clearly if all you care about is wet pavement grip, the right thing is a slick tire that's as wide as you can fit, and underinflate it very slightly.


Tom Forsyth said...

Those tables are pretty awesome. Let's take data for aircraft landing at anywhere between 100-200 knots, and extrapolate down to 20 mph, assuming it holds all the way down through an order of magnitude.

Though as he pointed out, perfectly reasonably, this stuff is trivially within the realms of actual testing on machines, and then we'd have an ACTUAL ANSWER.

Thatcher Ulrich said...

"steed", lol

old rants