13

Having used with great satisfaction puncture-resistant tires for more than 8 years, and having seen how it can happen than in professional races tires can be punctured, I wonder why are puncture-resistant tires not used from team racing in Giro d'Italia or Tour de France.

I am sure it is not for economic reason, but I cannot figure why.

Improve this question
9
  • 1
    As far as I can see, there are not many punctures in professional races (are there public data on that )
    – Max
    Jul 19, 2017 at 13:48
  • 1
    Remember that, when you watch a stage of the Giro or Tour, you're watching about 200 people cycle about 200km each. That's 40,000km of cycling -- no wonder there are a few punctures!
    – David Richerby
    Jul 20, 2017 at 1:37
  • 1
    @DavidRicherby on better and cleaner than average roads (I've been known to drive some TdF roads within a few weeks of the race and the difference is obvious when you join/leave the route). This keeps the number of punctures low.
    – Chris H
    Jul 20, 2017 at 13:45
  • 1
    @ChrisH Sure. But there are still some, and this is still unsurprising in 40,000km of cycling.
    – David Richerby
    Jul 20, 2017 at 19:53
  • 1
    @Kaz they typically swap the wheel or even the bike. But that still means stopping, including accelerating and decelerating time. And that means a lost place (subject to race etiquette)
    – Chris H
    Jul 20, 2017 at 21:27

3 Answers 3

Reset to default
49

To a racer, rolling resistance and handling top the list; durability is far down the list. The coefficient of rolling resistance (Crr) for a racing tire on typical French or Italian roads used during a Grand Tour is about .004, or even lower. The Crr of a puncture resistant tire can be > .01. Crr scales like gradient, so the difference between Crr's of .01 and .004 is like constantly climbing a slope of .006 (=.01 - .004), or slightly more than half a percent. On a 150km stage that's like climbing an extra 900m hill. No racer willingly gives up that much advantage, especially when there's wheel support from either a team car or neutral support (and for team leaders, a wheel swap from a team mate) should you get a flat.

Improve this answer
11
  • 5
    Right, the tubular tyres used by many teams for racing can have very low Crr. However, I've measured the actual Crr of clincher tires on smooth roads in France, and gotten slightly higher figures than "lab" values (although the ranking is almost always the same, so tires that do well on rollers in the bicyclerollingresistance lab almost always do well on the road). That's why I wrote "about .004, or even lower". I've measured Conti Gatorskins on an American road at .0104, and Specialized Armadillos above that.
    – R. Chung
    Jul 19, 2017 at 8:38
  • 5
    @ChrisH I think you are being overly optimistic Crr values. The values your quota are for high pressures on a drum roller. No one would run those pressures in the real world as the ride will be too harsh. Running the anti-puncture tires at more realistic lower pressures, almost doubles your quoted Crr values. On top of that real world Crr values will also be higher on real roads compared to the lab, for any given pressure. R. Chung already did this adjustment in his numbers. We should be careful to keep this an apples-to-apples comparison otherwise it is easy to mislead.
    – Rider_X
    Jul 19, 2017 at 13:27
  • 3
    It's because in the drag equation there are two coefficients of drag: Crr and Cd, where both the "rr" and "d" usually appear as subscripts to distinguish the rolling resistance coefficient from the aerodynamic drag coefficient.
    – R. Chung
    Jul 20, 2017 at 6:13
  • 2
    @Cat would you prefer $C_{\mathrm{RR}}$?
    – Chris H
    Jul 20, 2017 at 8:05
  • 2
    @cat It's actually Cₓₓ , so while Cxx is not good, CXX is even worse.
    – Agent_L
    Jul 20, 2017 at 12:58
20

Puncture resistant tires are heavier relative to non-puncture resistant tires. They also have sloppier handling/less control/higher rolling resistance, and are typically harder to change (though professional racers will usually wheel swap). And you have the question of rider preference -- you're going to set the type of tire + pressures and what not, the way the rider likes it (subject to sponsor and team and race requirements).

There are also some cultural aspects with mechanical failures (see also CyclingTips Commentary: Time to bid adieu to ‘gentleman’s rules’ in stage racing) -- you're expected to be gentlemanly towards the leader if he has mechanical failure with respect to not attacking (and you get criticized if you are not).

That being said, the CyclingTips article notes that some teams may be thinking about this to the point of sticking a bit of sealant in.

See What are the disadvantages of “puncture proof” (or puncture resistant) tires? for an extensive overview of the advantages/disadvantages in normal use. For a normal person who is not a racer, the advantages far outweigh the disadvantages.

Improve this answer
15

If you have set of identical riders, and one rider puts a slower tyre on, they will lose if no-one gets a puncture (let's simplify and assume a time trial so we can ignore effects of the peloton). Anti-puncture tyres are slower as seen in R. Chung's answer. Of course for a real race of merely very similar riders who may be having good or bad days, it's not quite as clear cut, but it undoes a lot of the marginal gains that are so popular.

Punctures in races are actually quite rare. The only time an anti-puncture tyre would come into its own is if all the other riders suffer punctures. For a normal road race, that would require sabotage.

Here's an old article that might be of interest.

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.