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#21
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Disc brake front wheel ejection: fact or fantasy?
"With so many amateur riders out there it's amazing that front wheels aren't
falling off left, right and centre" Amateurs are not the only ones who can screw up. About 6-7 years ago I was looking to buy a new bike. At a well regarded bike shop I was going to test ride a bike, the salesmen adjusted the seat and then gave the bike to the mechanic to check before I took it out. I don't know what he checked because the quick release on the front brake was open and with it open did not contact the rim enough to stop the bike. I tried to brake at a stop sign and no front brake. A car very nearly hit me as I crossed the highway. It was a very vivid lesson in who is responsible to check a bike before it is ridden. Check the brakes, check the skewers, bounce the bike and see what shakes, check the handle bars and seats to see there tight. That should take about 15 sec if every thing is ok and may be life saver if they are not Chris "Westie" wrote in message ... "Doug Taylor" wrote in message ... The boys (the girls are too sensible, it seems) in rec.bicycles.tech are going at it once again on this subject, with the tech heads and roadies basically saying that you are taking your life in your hands if you use disc brakes with QR's and regular dropouts on the theory that the QR eventually will come loose under force of the front brake and your wheel will pop off. So, my question is: has anybody who actually rides mountain bike with any frequency (such as the amb crowd) experienced this phenomenon or heard of anybody loosing a wheel? If so, any serious injuries? Is the sky really falling or can we get back on our bikes and ride? --dt Most likely more than half of the people out there that ride 'mountain bikes' have never heard of this issue and wouldn't know where to find a 'quick release skewer' on their bikes if they had to. Many of the pure recreational riders and Dewbies that I know just aren't interested in regular equipment checks. They'll check it if it happens, otherwise ignorance is bliss and they'll ride it 'til it breaks. With so many amateur riders out there it's amazing that front wheels aren't falling off left, right and centre. And not from braking forces - just from lack of proper adjustment. -- Westie |
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#22
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Disc brake front wheel ejection: fact or fantasy?
On Mon, 01 Sep 2003 16:53:10 -0700, Monique Y. Herman wrote:
I specifically asked a LBS about bike maintenance classes, and the salesguy claimed that he knew of no such thing in the area. Check your local community ed. Oh yeah, and other bike shops, assuming you have them. Stuff like adjusting your brakes and derailleur aren't that difficult once you know where the screws are. I've heard good things about _Zinn and the Art of Mt Bike Maintenance_, but can't vouch for it myself as I haven't found a copy yet. And there's always Sheldon "Hottie" Brown's website: http://www.sheldonbrown.com/harris/index.htm HTH gabrielle |
#23
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Disc brake front wheel ejection: fact or fantasy?
Alex Bird said...
Why would discs be more likely to release the wheel? This makes no sense to me. Alex There is a theory, conjured by one person by the name of James Annan, who rides a tandem mountain bike, and a few roadies who don't ride mountain bikes at all, that repeated use of the disc brake loosens the skewer, and when the skewer is loose enough, the brake ejects the wheel out of the dropout. There have been no documented cases of it ever having actually happened to anyone, except to maybe James Annan himself. Myself, Doug Taylor and Spider have been the main people taking the skeptical side of the debate over in rec.bicycles.tech. James Annan wants to attribute every wheel loss, and seemingly every off-road biking injury, to his pet theory. He is quite close-minded to any opposing viewpoint. I believe that it actually happened to him, but his was a very special case. He was on a tandem which can exert extreme forces in braking, much more than you would see on a single person bike. Worse, his fork was very poorly designed. It almost looked like it was built to have this failure. It had no retention lips and this feature alone would have almost certainly prevented the wheel from going anywhere. The fork also had a very odd dropout angle that slanted toward the rear and ran parallel with the brake rotor. Vertical dropouts would have resisted some of the ejection force. Now he is badgering bicycle manufacturers, journalists and the American Consumer Product Safety Commission, not to mention us on the Internet, that something must be done about it. The fact that almost nobody who actually uses bikes so equipped believes him or takes his scare tactics seriously doesn't faze him in the least. My opinion is that retention lips make this failure almost impossible. This opinion is backed up by the fact that nobody can find any cases of it happening to anyone but him. His bike didn't have them, the vast majority of bike sold in the US do and have for years. Europe may be different. |
#24
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Disc brake front wheel ejection: fact or fantasy?
gabrielle said...
On Mon, 01 Sep 2003 15:24:57 -0700, bomba wrote: Not quite the same thing. He popped a wheelie off a kerb, the wheel fell out, chucked him over the bars and the bike then somersaulted in to his head. Bet he couldn't do that again if he tried That was from 999, and was way longer than 3 or 4 years ago. I don't think they had disk brakes back then. gabrielle Oh yeah. William the Conqueror defeated King Harold at the Battle of Hastings riding mountain bikes. |
#25
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Disc brake front wheel ejection: fact or fantasy?
On Mon, 01 Sep 2003 18:33:25 -0700, gabrielle penned:
On Mon, 01 Sep 2003 16:53:10 -0700, Monique Y. Herman wrote: I specifically asked a LBS about bike maintenance classes, and the salesguy claimed that he knew of no such thing in the area. Check your local community ed. Oh yeah, and other bike shops, assuming you have them. Stuff like adjusting your brakes and derailleur aren't that difficult once you know where the screws are. I've heard good things about _Zinn and the Art of Mt Bike Maintenance_, but can't vouch for it myself as I haven't found a copy yet. And there's always Sheldon "Hottie" Brown's website: http://www.sheldonbrown.com/harris/index.htm HTH gabrielle Thanks for the pointers. I have to admit to being a bit wary of shifters -- I tried to "tune" the gears on a bike I had while in college on the theory of, "How complicated could this possibly be?" ... Needless to say, with no knowledge whatsoever, that bike never shifted properly again. The best way to deal with a fear is to meet it head-on, though, right? -- monique |
#26
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Disc brake front wheel ejection: fact or fantasy?
Doug Taylor wrote in message . ..
The boys (the girls are too sensible, it seems) in rec.bicycles.tech are going at it once again on this subject, with the tech heads and roadies basically saying that you are taking your life in your hands if you use disc brakes with QR's and regular dropouts on the theory that the QR eventually will come loose under force of the front brake and your wheel will pop off. Roadies and especially the bunch at rectum.bisexual.techsticles are a bunch of sissy punkasses. JD |
#27
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Disc brake front wheel ejection: fact or fantasy?
Super Slinky wrote in message et...
There is a theory, conjured by one person by the name of James Annan, who rides a tandem mountain bike, and a few roadies who don't ride mountain bikes at all, that repeated use of the disc brake loosens the skewer, and when the skewer is loose enough, the brake ejects the wheel out of the dropout. The fact that almost nobody who actually uses bikes so equipped believes him or takes his scare tactics seriously doesn't faze him in the least. The fact that trolls like yourself lie about me on usenet certainly doesn't faze me in the least. I'm not stupid and I realised right from the start that with so many powerful vested interests involved I was going to end up the scapegoat anyway, it's tough **** but that's what whistleblowers have always got for their trouble. I don't want it to be _my_ campaign but neither am I prepared to sit back and do nothing while the manufacturers stick their heads in the sand and riders continue to get seriously hurt by this design fault. Several of the journalists who have written about this (and who all agree that there is a real problem, having reviewed the ample evidence in its favour) are in fact trained engineers with long experience in the bicycle industry, and some of the most respected expert witnesses in bicycle liability litigation bar none (also trained engineers) have stated their clear opinion that there is a dangerous fault. Many people have now replicated the phenomenon by themselves, no special equipment required, and it is increasingly ridiculous that the manufacturers pretend they don't know about it. Some people who work in the industry, who know for sure there is a problem, have stated that they don't want bodies such as the CPSC involved precisely because they _do_ know there is a real problem, and it's going to cost someone quite a lot of money to fix. Of course, the longer this drags on, the more it will cost when it eventually does get fixed. But you'd rather attack me than actually ask the manufacturers for some answers. That says plenty about your motivation and interest in this problem. Never mind, it will eventually be solved, but it will be despite your contribution rather than with the help of it. You may think you are saving the manufacturers from unnecessary interference, but you are actually encouraging them to dig their own graves. I hope you are proud of yourself. James |
#28
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Disc brake front wheel ejection: fact or fantasy?
"Doug Taylor" wrote in message ... The boys (the girls are too sensible, it seems) in rec.bicycles.tech are going at it once again on this subject, with the tech heads and roadies basically saying that you are taking your life in your hands if you use disc brakes with QR's and regular dropouts on the theory that the QR eventually will come loose under force of the front brake and your wheel will pop off. So, my question is: has anybody who actually rides mountain bike with any frequency (such as the amb crowd) experienced this phenomenon or heard of anybody loosing a wheel? If so, any serious injuries? Is the sky really falling or can we get back on our bikes and ride? There has been much discussion over this issue on singletrackworld.com, not surprising really as the issue is very close to some of the regulars. As far as I can tell there has been no conclusive proof either way, although some independant testing has shown that vibration from disc brake forces can lead to a loosening of the Q.R. nut the testing has not been rigerous enough to draw a verifiable conclusion. I believe its an issue that should continue to be discussed. Just because it hasn't happened to you, or to anyone you know doesn't mean it can't happen. A bodge solution was put forward on the STW forum: http://www.singletrackworld.com/foru...528093#reply_5 28933 basically it involves using a jubilee clip (hose clamp) to clamp round the Q.R. nut with the jubilee nut resting against the fork dropouts, resisting loosening. If anyone is really interested there are a few more interesting discussions on the following threads: http://www.singletrackworld.com/foru...523608#reply_5 26529 http://www.singletrackworld.com/foru...531565#reply_5 33475 http://www.singletrackworld.com/foru...553505#reply_5 54322 Steve. |
#29
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Disc brake front wheel ejection: fact or fantasy?
Doug Taylor wrote in message ... The boys (the girls are too sensible, it seems) in rec.bicycles.tech are going at it once again on this subject, with the tech heads and roadies basically saying that you are taking your life in your hands if you use disc brakes with QR's and regular dropouts on the theory that the QR eventually will come loose under force of the front brake and your wheel will pop off. So, my question is: has anybody who actually rides mountain bike with any frequency (such as the amb crowd) experienced this phenomenon or heard of anybody loosing a wheel? If so, any serious injuries? Is the sky really falling or can we get back on our bikes and ride? Well, I got a Hope Mini on the front, with the big rotor, bike is heavy and so is my pack. Big bad grippy knobbies, and I don't half hammer on that brake lever some times when coming to a stop - _never_ had a problem, not slight, not at all, never. I do get _very_ medieval on my QR skewers though (closed 'em with my feet before now......), enough that I'm worried for the life of my dropouts, heheheheh.......... This is my own experience only, obverously. Shaun aRe |
#30
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Disc brake front wheel ejection: fact or fantasy?
bomba wrote in message ...
Not quite the same thing. He popped a wheelie off a kerb, the wheel fell out, chucked him over the bars and the bike then somersaulted in to his head. Bet he couldn't do that again if he tried I'm willing to bet he hasn't tried. That was from 999, and was way longer than 3 or 4 years ago. Nah, twas no more than five years ago, I remember where I was when I saw it. |
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