We talked about the benefits of tubeless tires and wide rims, and I cannot help but find myself being an evangelist for both! I was just reading through a copy of Bike Mechanic: Tales from the Road and the Workshop by Guy Andrews and Rohan Dubash. In it, they recount a discussion with a renowned bicycle maker who suggested that “tire choice and pressure could have an equal or greater influence on a bicycle’s overall ride quality as the material from which it is made.”
A tire is made up of three parts: the bead, the sidewall, and the center strip/tread. The bead locks the tire securely into the wheel rim, and clincher tires and tubeless tires differ a lot here. Unlike clincher tires that hold air via the inner tube, tubeless beads need to lock in and allow no air to escape once the sealant is added. This sometimes makes them harder to mount.
The sidewall stiffness affects the overall suppleness of the tire. Fast race tires often have supple high thread count sidewalls/casing which allows the tire to more easily shift and confirm to the road in a way that lowers rolling resistance and makes the tire faster. However, supple casings are more prone to punctures. I remember the first great set of tires that I put on my bike, Vittoria Corsa CXs. They were so supple and so fast. And they punctured when you looked at them. Ugh!
The center strip/tread is also critical to the tire’s performance as the rubber that makes it up greatly affects rolling resistance and susceptibility to punctures. Some compounds like that on the Vittoria Corsa Speed are superfast but not very puncture resistant. Some others, like those on Continental Gatorskins are almost puncture proof, but they ride like you have garden hoses glued to your wheels. *
(I don’t know if that makes sense, but if you try them it will!).
Contrary to some people’s beliefs, the tread on a road tire has a negligible effect on grip and cornering. The volume, pressure, and the rubber compound used have a much greater effect. Tread thickness makes a difference on puncture resistance, but file treads aren't much better grip-wise even though they look like they would make a difference.
So why do tires make such a difference to a bike's ride feel? They are the only real shock absorption that a bike has, and the pressure, shape, and compound all affect cornering and rolling resistance.
The best tires are matched to the roads we ride on, and at best they are always a compromise. The bead, sidewall, and tread all interact to