Bicycle Mechanics - Rear quick release problem
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05-25-05, 01:15 PM
Why would a tightly closed rear quick release not hold my rear wheel on? QR done up tightly but wheel came out of frame while cycling. QR still closed after tumble.
How tight is tight?
About three quarters down.
Make sure the cone/washer/locknut assemblies are correct and that there is not too much axle protruding past the locknuts, otherwise the QR ends will bottom out on the axle instead of gripping the dropout.
05-25-05, 05:12 PM
Thanks for those. I shall check on Friday when I get to see the bike again. Great link to Parktools, cheers...
05-25-05, 07:48 PM
This is a classic problem. The axle cannot be protuding outside of the dropout. Not at all. It should be about 1.5-2mm short of flush with the outside surface of the dropout. If it's flush, or protuding, the axle will pull out when you lean down on the crank on that side. There are a couple of things that can cause this problem. One, your axle may not be centered between the locknuts. There should be exactly the same on both sides and (once again) that amount must be less than the thickness of the dropout. If the two sides are not equal, then you will need to readjust everything on the axle to eliminate the offset. Two, it may be that for some reason the axle is too long. Did you replace it? If it is too long, then cut it down so that does not come flush or protude. A third possible problem is that a spacer or washer did not make it back on to the axle during reassembly. Measure the distance between the outside surfaces of the locknuts. On most bikes it should be 130mm. Some MTBs will be 135mm. Older road bikes maybe 126mm. You can measure between the insides of the dropout to find out what it should be (if that, for example, measures 131mm, then your hub should measure damn close to 130mm). There are likely more possible reasons, but I believe these would be the common pitfalls. If the "flush or outside" rule is violated, no amount of tightening of the QR is going to fix the problem. You'll likely end up stripping the adjustable side.
05-26-05, 09:21 AM
Aside from the good advise that the others have given above, you might just have a skewer that doesn't clamp very well. Some roadies who ride 'botique' wheels find that the skewers supplied slip under heavy sprinting, etc. no matter how hard they are clamped down. The solution is usually to replace the offending skewer with one of the classic design from Campy or Shimano.
05-27-05, 10:42 AM
Thanks, especially Cascade, for a comprehensive answer. I have now looked closely at the bike (an old Specialized MTB). The axle finishes about 1.5mm inside the dropouts on both sides. The width between dropouts is 135mm. I thought that because the QR was still locked when the wheel fell off it could not be strength of QR.
I took it to a bike shop to see if they could shed light (without any great faith). They concluded that the the QR knurled bits were just plain worn out and so not gripping the dropouts adequately. I have replaced QR with Alen bolt equivalent. cheers for the responses. I now know more than I did.
05-27-05, 12:08 PM
see my previous post with this problem, do a quick search
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