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Ask Nick: Tire disaster, the wheel behind the sticker, sequential shifts

  • By Nick Legan
  • Published Jan. 14, 2011
  • Updated Feb. 8, 2011 at 7:20 AM EDT

Editor’s Note: VeloNews tech editor Nick Legan is a former ProTour mechanic who most recently wrenched for Team RadioShack at the 2010 Tour de France and elsewhere. His column appears here every Friday. You can submit questions to Nick at asknick@competitorgroup.com, and be sure to check out Nick’s previous columns.

Beloki's career-altering crash.


Q. Nick,
As a bigger guy who really likes to push it on the downhills I’ve never been able to shake the image of Joseba Beloki’s rear tire unseating on the descent into Gap whenever I consider tubulars. How common an issue is that really? Since then, have you ever heard of pros using a heavier clincher setup on a hot day with a treacherous downhill just for the extra security of the rim staying on the bead? Or is Beloki’s crash written off as a freak occurrence with a hot day, hard descent, and potentially less than optimal tire install/line choice/braking point?
— Troy Browning

A. Troy,
You’ve asked a series of questions here and I’ll answer them all. But first I think it’s best to examine what happened that hot day in July of 2003. I watched Beloki’s crash live that day and since then I’ve seen the video more times than I care to remember (including a couple more times before replying to your question).

Beloki’s tire rolled as a result of his slide, it didn’t cause the slide. On a slick tar patch, his rear wheel lost traction under braking and when it almost instantaneously regained traction, Beloki high-sided. The tire rolled because he was sliding sideways. Even the best installed tubular will roll under extreme side loads.

Lance Armstrong had a similar crash at the 2010 Tour, though he was obviously able to continue. We at the hotel in St. Moritz heard that Armstrong had rolled a tire and went down. We collectively started to sweat. When we saw the wheel in person, we realized that our glue job was better than Hutchinson’s. The base tape was still attached to the rim bed. The tire casing had delaminated from its own base tape. It’s important to point out that this was NOT a failure on the part of Hutchinson or the mechanics that glued it on. Sometimes tires come off as part of a crash.

Sustained braking saturates a rim and tubular glue with heat. This is what leads to a tire rolling. In the old days, riders were taught to alternate between braking and coasting. This allowed the rim to cool between applications of heat. If a cyclist rides the brakes all the way down a descent, most rims will have a difficult time dissipating the heat created by braking friction. This heat finds its way to tubular glue and…game over.

Tubular tires very rarely roll when they are professionally glued. It is seen more in cyclocross than in any other discipline. I’m not a physics professor, but it is due to the high traction that lower pressures and wider tires create. This traction keeps the tire in place and under cornering forces, the tire is leveraged off the rim.

If a team finds that tires are rolling, a mechanic won’t be around long. USA Cycling used to hand out heavy suspensions to any racer who rolled a tire in competition.

I’ve never heard of pros using clinchers for safety reasons on any occasion, be it a hot day with descending or not. In fact, carbon clincher wheels have historically had their own host of braking heat dissipation problems. And I have heard of clincher tire sponsored riders switching to tubulars on climbing days.

Bear in mind that Beloki is not a big guy. His size didn’t really play much of a factor in his horrible crash. Hot tacky asphalt and misjudging his speed doomed Beloki. It was certainly a bad crash, but those occur in races all the time.

Mark Cavendish's broken front wheel.


Q. Nick,
I have another question about a photo in your recent Zipp factory tour feature. The photo of Cav’s smashed wheel from the Tour de Suisse is clearly a Zipp 404 with the 88 hub. According to the VeloNews 2010 Tour de France Guide as well as HTC-Columbia’s website, the team is sponsored by HED. Cav himself is not sponsored by Zipp (Nike and Oakley are the only personal sponsors listed on his website). So what’s the deal there? Is that why HTC is the only team to take off all decals and replace them with their own Highroad decals? I surely am not the first one to notice this, right?
— Dave Cifelli

A. Dave,
My understanding of Columbia-HTC’s wheel sponsorship is a bit hazy. In past seasons I’ve seen Shimano, PRO, HED, Lightweight and Zipp wheels used, many of them concurrently. Officially, HED sponsors the team. But it has always been clear within the pro ranks that Columbia-HTC often buys whatever they feel is fastest and race them with only Highroad logos. Cavendish has often raced Zipp wheels and that is why his wheel was at the Zipp offices. As I mentioned in the Zipp piece, Cavendish actually rode that wheel across the line after he picked himself up.

Wheels are one area where a lot of rebranding occurs. Some of it is very upfront. Bontrager buys Lightweight disks for Radioshack and now Leopard-Trek and stickers them with huge Bontrager logos. In the past there were rumors of Armstrong racing on Zipp disks that were rebadged.

I’m sure you’re not alone in noticing this, but it’s a fairly open secret that Columbia-HTC isn’t HED sponsored in the strictest sense. It’s also nothing new for the team. Back in its T-Mobile days the team raced plenty of non-sponsor correct wheels. Bjarne Riis raced on Lightweight wheels as early as 1996 (perhaps earlier) when he was sponsored by Campagnolo.

It will be interesting to see if Columbia-HTC starts the 2011 season using only HED wheels. Stay tuned for Tour Down Under photos.

Q. Nick,
As a mechanic I work on all sorts of systems, including Di2… I got to thinking. If it’s an electronic system why do you need front AND rear shifters? Why not use a single shifter and simply have 20 sequential gears? Each shift moves you up or down one gear from 1-20. A simple computer chip can be pre-programmed so the chainring/cog combinations can be ordered properly. No more shifting front AND rear to find the next gear in the sequence. You just ask for the next tallest gear and you get it. Just curious if something like that is in the works or even makes sense to anyone besides me.
— Mark Bertram

A. Mark,
You’re not alone in your thinking. Fairwheel Cycles in Arizona has already built a mountain bike using modified Di2 components that uses a single shifter. It is a matter, like you say, of reprogramming. I wouldn’t be surprised if one day Shimano and its future competitors offer sequential shifting as an option.

For now I think that Shimano made a wise decision in sticking with a more traditional setup. Most riders think in gear combinations, not in sequences. We talk about them in sometimes excruciating detail after a group ride. As I ride, I’m normally very aware of the gear I’m pedaling. Part of the fun of riding is gutting it to the top of the local short and steep climb in the big ring. Ego is part of why we ride, for better or worse. There are also times when it doesn’t make sense to shift chainrings even though a combined chainring and cog shift would get the next largest gear development.

It’s an interesting idea and one that we were never been able to entertain until Mavic Zap came along. But if the time, expertise and money are at your disposal, go for it! (then send it to me for a test ride, love to check it out)

Q. Nick,
How do the big races keep up with the individual riders? I have noticed a small box on the rear chainstays of some bikes and assumed it was a tracking device of some flavor. I can understand if that is some kind of GPS unit, but what happens if a rider changes bikes during a stage (mechanical failure, crashes, etc)? I doubt that there are multiple trackers for each rider. How does the magic happen? — Steve Harvey

A. Steve,

The ubiquitous transponder.

At many of the grand tours, the race organizer provides a transponder that is attached to either the chainstay or the fork. That’s what you’re seeing. They aren’t GPS units, just coded transponders that are received by a sensor across the finish line. Some local races are beginning to use the exact same technology.

Each rider is assigned one transponder for his race bike. As you mentioned, if a rider changes bikes due to a mechanical issue or a crash, he won’t have his finish recorded by transponder. That’s where the finish camera and good old-fashioned officiating come into play. Usually officials will contact a team if one of their riders wasn’t given a placing at the finish and the officials didn’t notice them in a crash. That’s why you see riders who abandon a race tearing off their number. An official will take the number and the rider’s abandon will be recorded.

Television has started to use some GPS tracking devices to see where a number of riders are at a given moment in the race. But I’m not aware of governing bodies using that technology for the entire field just yet. As devices get smaller and smaller it makes sense that one day each bike, both race and spare, will be tracked (or simpler still would be a GPS-enabled race number).

Until then, we’ll have to count on our officials. It’s amazingly old school sometimes but for the most part it works very well.

FILED UNDER: Ask Nick / Bikes and Tech / Technical FAQ

Nick Legan

Nick Legan

After graduating from Indiana University with honors and a degree in French and journalism, Nick Legan jumped straight into wrenching at Pro Peloton bike shop in Boulder for a few years. Then, he began a seven-year stint in the professional ranks, most recently serving for RadioShack at the Tour de France and the Amgen Tour of California. He also worked for Garmin-Slipstream, CSC, Toyota-United, Health Net and Ofoto. Legan served as the VeloNews tech editor 2010-2012 before sliding across the line into public relations.

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