Go to these two links for an explanation.
My understanding is from those two links, so read those rather than my muddled interpretation. The basic problem is some Trek bikes were supplied with a quick release lever that seems to open so far that it can get caught in the brake rotor. If your bike is one of them, please get it fixed. Its too easy to forget these things until the "holy shit" moment.
I checked my Salsa LaCruz and Specialized Stumpjumper, which have disk brakes. These QR doesn't even open 180 degrees, so cannot interfere with the brake or wheel if they open up. The QR on my Surly Long Haul Trucker opens a little past 180 deg but not enough to extend beyond the fork blades and interfere with spokes. I checked 8 other front wheels with a variety of brands of skewers (Campy, Shimano, Salsa, Bontrager). I did find one QR lever that extended well beyond 180 degrees. It almost touched the spokes, but on a loose wheel and if there was a fork tip in the way I don't think it would reach. It is a really old QR skewer on a circa 25 year old Shimano 600 hub/wheel left over from my racing days.
Loose quick release skewers are a failure mode of quick releases. Quick releases, in my opinion, are a convenience device added to bicycles and they require the operator (not the bike company or your mother) to be educated and diligent to make sure they are ALWAYS TIGHTENED PROPERLY. Retention tabs, aka "lawyer tabs" are a failsafe added after lawsuits happened.
I never even thought of this particular failure mode, i.e., the quick release lever getting tangled up in the rotating bits, before today. Generally, as a League Cycling Instructor, I tell people that the failure is the wheel being loose in the fork, compromising handling, or potentially falling out with all hell breaking loose if the "lawyer tabs" don't hold. I suspect someone failed to do a failure mode analysis, or someone got a defective bunch of skewers that were not tested. Oops.
Teachable moment, eh?
Add this thought to your Quick Safety Check: Can anything open up, fall off, or come loose in a way that will cause an instant and catastrophic failure? Take a good look at your bicycle and its critical components. Fiddle with them. If you see something that leaves you wondering "is this rather strange?", take a closer look or get a second, qualified opinion.
The video below courtesy of the League of American Bicyclists.
3 comments:
Reminds me of the Cannondale recall due to them not installing "pie plate" guards between the cassette and the spokes on their high-end bikes. That situation also had theoretical risk of injury or death in the eyes of lawyers that don't cycle.
In the modern U.S. world where there is a push to get more and more people on bikes, a lot of them are not going to be familiar with the intricacies of modern bicycle technology, which is often designed for enthusiasts. Bike companies have to do a good job of checking for these failure points, because non-cyclists taking up cycling may not.
Steve, this one had actual injuries. I do think root cause here is trying to make a loose QR acceptable via the...what's the proper name again? Retention tabs? Sometimes trying to make a failure mode safe just moves the problem to another failure mode.
Nor do I disagree with Khal's point!
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