jyl

In auto and motorcycle road racing, tires are as sticky (high traction) as possible, and only last as long as the race does (or less, if the rules permit tire changes).

Why aren't road racing bicycle tires the same way? At least for stages with a lot of descending, where faster cornering can gain minutes? I'm thinking tires with soft rubber, giving the rider maximum traction in hard corners, especially in the wet. They only need to last 200 km for most races.

(I am talking about actual professional racing, where the mechanics service the bikes after every stage, and could change wheels and tires daily.)

Bill Kapaun

If the tires were actually "sticky", it would slow you down on the straights. Think about the energy one would waste. It would be akin to riding in molasses.

Rubber thickness also provides flat protection. Do you really want to be running on the fabric at the end of a race?
"Race" tires aren't going to have stiff, flat resistant "barriers" in their construction.

Andrew R Stewart 

Generally bicyclists rarely get close the tire's traction limits during riding, cornering includes. And when a rider crashes the cause is almost never a loss of traction in a manor where the tire's grip was the cause. Crashing causes are usually due to impacting other riders/cars/trees, and/or riding over rough/pot holed/rocky/rutty roads/trails (causing the tire to loose contact with the ground). All are the responsibility of the rider to deal with safely, not the tire's. Over 100 years of rider's choices and market offers have brought us to where we are now. This history is not wrong.

What does happen in pro racing is tire choices which minimize weight and air drag and/or maximize flat proofing. (The exception is off road riding where traction is FAR more an issue). And in pro racing replacement tires (as in wheel changes) are done all the time already. Andy.

Looigi

+1. I raced motorcycles and would wear out a set of tires over the course of a weekend of practice and racing. Guys riding superbikes could wear out a set in a single race because they are right at the edge of traction limits corning, accelerating or both for much of the circuit. On a bicycle, you very very rarely get close to traction limits, and the benefits of being at traction limits are much less than in motor racing.

Retro Grouch 

Actually, the fastest bicycle racing tires already don't last very long.

To minimize rolling resistance what you want is a very thin, very supple tire. If you were to reduce the tread rubber covering, you could decrease rolling resistance, but at the expense of tread wear and puncture resistance. In a bicycle race, puncture resistance is probably a much bigger deal than a minimal reduction in rolling resistance would be.

dsbrantjr

Why aren't bikes built that way? By that logic, if they last more than one race they must be overbuilt, right?

jyl

I'm thinking of a racer charging down a twisty mountain descent, taking every corner banked over and as fast as he dares. That doesn't happen in most stages, and only a few racers in the peloton are desperate to gain minutes on these descents. Think the sprinter who has lost time on the climb and is trying to regain contact on the descent, while the non-sprinter teams are doing their best to keep him dropped. Those few riders are, I think, traction-limited in the descents. Maybe for that stage the mechanics could fit special cornering tires with soft tread shoulders.

Along similar lines, I've wondered if team use special tires for wet stages or for cold stages (e.g. rubber that stays soft at low temperatures).

As far as I know, the only time when pro teams use special tires are for cobbled races, e.g. Paris-Roubaix where today many riders are on 28-30 mm tires.

jyl

Maybe but the UCI weight limit makes it moot.

fietsbob

You mean starting and finishing 1 days racing on the same wheels? Glued on Tubulars?

200km is just under 125 miles.

jyl

Right, conceptually the idea is the center of the tire tread would be pretty normal but the shoulders, which is what you use for hard cornering, would be very soft and sticky.

Bill Kapaun

"Sticky" could pick up debris which could make things bad.......

fietsbob

OK conceptually ..

but as a manner of practice classic Tubular tires dont have the 3 compound treads

of many tires hawked to the Tifosi that think they need the sticky high speed cornering, edges ..

FastJake

There are track tubulars that are very thin and light, something like 180g for a complete tubular tire. But they're too fragile for road use. I think if road race tires were any thinner they'd get punctured too often which would offset any tiny benefit of being lighter or stickier.

Road racing bikes are already very light and would be even lighter without UCI regulation. It's not a matter of wear but making them strong enough so they don't break during the race. It wouldn't look good to see Trek's latest carbon wonder fold up like an accordion on the Tour.

There are a couple things like what you're talking about though. Aluminum cassettes for example. Lighter than steel or titanium but extremely short life. But really, there aren't that many "wear items" on a bike that could be taken advantage of for performance or weight. It's not like bikes have engines that spin at 20,000 RPM and require rebuilding after every race. Though we might get to that point if doping technology improves enough...