Monday, March 30, 2009

Rolled Tubular at World Track Championships--Who's the Hack?

As an amendment to this post, Dave was kind enough post a link to video of the crash. As you can see, the tire popped off when Kevin Sireau lost control of his bicycle. I still maintain that the glue job was garbage, watch how easily the tire broke free:

I guess that I have to ask: would Sireau have been able to recover and avoid the crash if his tire hadn't rolled, or was he a goner by the time the tire came off?

Sometimes tubular tires roll. A weak joint is able to work itself loose and then the rider hits a hard bump while the weak spot is gripping the pavement, usually while cornering. The result is that the tire breaks free. When the glue job is good, most of the tire will remain adhered to the rim, though the rider still crashs. Even in cyclocross, where lower tire pressures make the glue job that much more important most of the basetape remains attached.

These photos are remarkable for a number of reasons. Firstly, notice that the tire is completely off of the rim, even before the rider hit the deck, as if it was not glued at all. Secondly, notice that the other rider remains upright even after being bumped pretty hard at the end of a sprint. Thirdly, in the last photo, notice that there is no evidence of glue on any part of the offending rim.

My question is: who the hell glued these and shouldn't they be sanctioned for negligence? If a cat 4 rolls a tubular in a criterium USACycling has the right to fine and/or suspend the rider.

While these photos have gotten wide circulation, there has been no comment on how tubular failure appears to have caused this crash.


zack said...

Could have flatted right before and the lateral force on the tire could have pushed it off. Remember in a road glue job, you aren't so concerned about the amount of glue on the edge of the rim since 150psi will hold it on pretty well with no glue at all. Next time you stretch your road tubbies, try rolling them off when they are completely inflated.

RMM said...

I am not so sure.

If it isn't difficult to rip the tire off the rim, I think the glue job is weak.

Tire pressure will hold the rim on when I use my fingers to try to pull it off, but if I took that rim down a hill and tried to corner...

gewilli said...

he was probably using tape

Dave said...

looks like crash the crash caused the tubular to roll rather than the tubular rolling causing the crash. Watching Bauge keep the rubber side down is amazing.

Anonymous said...

To me it looks like the front wheel lifts off the track and that's why the bars turned. The tire may have pulled off when the wheel came back in contact with the surface. Once the bars turned he was done for no matter what I think.


solobreak said...

Track people would not use tape. At this level they would most likely use something as "hard" as possible, like a shellac, to minimize squirm and rolling resistance.

The consensus on the track forums seems to be that this tire was not glued on at all. The team probably has numerous wheelsets and somehow and unglued wheel found it's way onto this guy's bike in the medal round...

Everyone seems to note that the tire doesn't come completely off until the guy is already in the process of crashing. I think it's likely the insecure mounting would have contributed to the loss of control in the first place. He's riding on the absolute limit and if the tire squirmed in the slightest that could have caused the intial bobble, even though it's not possible to detect such a thing on internet video.

zack, please don't even think about riding an unglued tire in a road race. Tire rolling may be more common in cx, but at least then you usually only take out yourself, and at low speed. When you hit a bump in a corner at 50kph, leaned over as far as you can go, the forces are more than enough to roll an insecure tire, and the consequences can be very severe.

zack said...

Oh man, I've been riding unglued tubulars for years with no problems! I think I'll still continue, no problems yet.

Nobody has mentioned, but the basetape could have separated from the tire from a poor stitching job. I've had faulty tubulars where I've gone to remove the tire, and the basetape stayed on, and the rest of the tire came off like butter.

RMM said...

If I owned the wheels, I'd be pissed either way, since that nice Mavic wheel got more abuse without the tire than it would have if the tire remained where it belonged.

The monetary value of that front wheel rivals and likely exceeds the value of a gold medal at track worlds.

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