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#1
08-10-2017, 01:08 PM
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Rear wheel shifting position
I have experienced what I consider to be very odd a few times. My memory is vague on the circumstances of the previous times but I am fresh from it happening yesterday.
I was track standing on my bike at a red light. When it turned green, i tried to go. I was able to get through the intersection but knew something was wrong. Got off my bike and immediately noticed that my rear wheel was slammed against my brake. I opened the quick release (which was tight), reset the wheel, closed the skewer and went on my way. I did not notice the extreme braking as i was slowing for the intersection so i have to conclude that it happened due to the forces of the track stand. My skewers are tight. I actually have a hard time closing them. It seems like the adjustment on the nut end makes the skewer easy to close then practically impossible to close in a very small turn. Details that may help: I am about 200 pounds Frame is titanium skewers are not weight weenie. Hope brand quick release. The other instances: 1. at the bottom of a hill. Someone else had installed the wheel that day coming off a trainer (at LBS). Figured it wasnt tightened enough. 2. turning into my driveway. my neighborhood has sloping curbs so the transition is not as smooth. No idea. end of a 15 mile ride. 3. pulling a trailer. just happened on a flat. figured it was due to the trailer. I assume i am going to get a majority response that my skewer is not tight enough. I am hoping someone has another idea... 
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#2
08-10-2017, 01:11 PM
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External cam QRs like the Hope or Salsa are probably not providing enough clamping force. Something like a Shimano or Paul Comp internal cam would likely do a better job. I'd say your QR is probably tight, the design just doesn't clamp well enough for a campy style dropout.
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#3
08-10-2017, 01:13 PM
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this is known to happen on titanium frames and those with chromed dropouts. the dropout is very hard and the QR doesn't "bite" hard enough to prevent slippage.
ditch those hope skewers, yes, they are very good, but in this situation you require some extra clamping force, get a set of dura ace or record closed cam skewers and clamp em down. it may also help to scuff up the dropout faces, both inner and outer to give the hub face and QR a better chance of getting some friction.
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#4
08-10-2017, 01:21 PM
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Wheel axles slipping in titanium frames is actually a known problem. Some titanium manufacturers use 6/4 alloy titanium for dropouts because it is very strong. It also have very high surface hardness, so axles and skewers have more difficulty digging into the surface for good grip.
As noted, external cam skewers may not generate as large a clamping force, so you may want to switch to internal cam skewers. Also, axles and skewers with knurled steel faces will dig into the titanium dropout better for better grip. (Also note that stomping on the pedals in a small chainring generates very large forces trying to yank the wheel forward in the droputs. The cranks/chainring acts a lever, which amplifies chain force pulling on the wheel. A 175 mm crank and 39 tooth chainring will amplify pedal force by a factor of 2.2, so if a 200 lb. rider stands with their weight the pedal, it will generate a 440 lb. force trying to pull the wheel forward.)
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#7
08-10-2017, 10:03 PM
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Quote:
I'll admit it. I had to look it up. Though, as an adult, I've only experienced the horizontal type on my 2 yr old's bike.
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#9
08-10-2017, 10:10 PM
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I had the same problem when I had an Eddy Merckx Majestic titanium bike, made by Litespeed. It had semi-vertical dropouts and they slipped unless I had the Campagnolo (internal cam) skewers cranked down as hard as they would go.
I've gotten rid of all my external cam skewers and now use Campagnolo and Shimano exclusively. They have way better clamping force. They weigh a bit more but I feel much more secure with them.
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#10
08-11-2017, 08:55 PM
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If using Shimano cup/cone hubs, be sure that they are adjusted after installation using such high-tension QR levers, as the axle compresses measurably in response to the thousand pounds or so of compressive force.
On older Shimano hubs, some bearing free-play needs to be adjusted into the axle before installing the wheel. I had an old Viscount bike with nice, hi-flange QR hubs that oddly used brass toothed locknuts, and I couldn't keep the axle from slipping before I finally replaced the drive-side locknut with a steel one. Due to today's very light bike weights being effectively overcome by cage spring chain tension, I always advise applying weight to the bike's saddle when flipping the QR lever closed. It's the best way to seat the axle fully in the exact position that gravitational impact forces will eventually try to move it to, so may prevent certain cases of slippage or of a wheel dropping out altogether while riding (something I've seen).
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