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#1
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Rear wheel off-center
After overhauling my rear hub and reassembling the bike, the wheel is
now off center by 2-3 mm. This is a bit puzzling, since I reassembled everything exactly as it was originally and I did not loosen or adjust the axle locknut on the drive side. The problem is wheel related (after flipping the wheel, it's off-center in the other direction) and the wheel spins true. I could fix this by adjusting the axle, but then there would be very little of the thread showing on one end where it slides into the frame's wheel slot. Anyone have a clue what happened? |
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#3
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Aha...there was an extra bearing on one side. I checked for this
before, but not carefully enough and it was hard to see. Some extraneous bearings had fallen out of the seatpost tube (left there during original assembly) and I must have put one of them in. |
#4
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In article ,
A Muzi wrote: wrote: After overhauling my rear hub and reassembling the bike, the wheel is now off center by 2-3 mm. This is a bit puzzling, since I reassembled everything exactly as it was originally and I did not loosen or adjust the axle locknut on the drive side. The problem is wheel related (after flipping the wheel, it's off-center in the other direction) and the wheel spins true. I could fix this by adjusting the axle, but then there would be very little of the thread showing on one end where it slides into the frame's wheel slot. As you note, professional mechanics always remove axles from the left. That was the right thing to do. You don't say what hub or to which side it is off. Normally we don't separate the right side components between cone and outer locknut. If you did, it's easy to transpose a thick spacer for a thin one or move two spacers to one side where there was one each side before. Is it possible you miscounted ball bearings? Either one too many or simply a ball out of place might do that - but then you'd be short of thread too. The only other thing that comes to mind - and I've seen it done - is possibly a cone flipped over - square side on the bearing? That's all good advice from Mr. Muzi, but he must have overlooked a simple(minded?) cause: the wheel is dished, i.e. the rim not centered between the locknuts. I probably was that way before the OP worked on the hub, but was not noticed if the rear brake was a) a rim brake adjusted to compensate, or b) absent. Flipping the wheel over is a classic method of determining if it's the wheel or the frame that's askew. -- Ted Bennett Portland, OR |
#5
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wrote:
Aha...there was an extra bearing on one side. I checked for this before, but not carefully enough and it was hard to see. Some extraneous bearings had fallen out of the seatpost tube (left there during original assembly) and I must have put one of them in. As a basic habit, clean everything, wipe your tools, wash your hands and then open your bearing packet, laying the balls in a line of fresh grease. Reusing balls is false economy - a complete waste of your time - and worse when you mix left with right or balls from another system. Bearings are sold and priced on how alike, not how round, they are. If you should mix them, you would end with some larger and some smaller than others. The result is all the bearing's load on the one or few larger balls, hence faster wear. Unlike human comestibles, there is no '5-second rule' for ball bearings - we _never_ retrieve one from the floor. Premium Grade 25 Chrome Steel balls are dirt cheap and are sold in matched sets. Grade 25 means less than 25 millionths of an inch variance within the lot. (Campagnolo, in metric, says 'uno milionesimo'). Usually around two bucks for all that! -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
#6
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On Sun, 06 Mar 2005 00:40:09 GMT, Ted may
have said: That's all good advice from Mr. Muzi, but he must have overlooked a simple(minded?) cause: the wheel is dished, i.e. the rim not centered between the locknuts. If you read the OP's response, you'll find that one of the possible causes cited was precisely on target. I probably was that way before the OP worked on the hub, but was not noticed if the rear brake was a) a rim brake adjusted to compensate, or b) absent. Flipping the wheel over is a classic method of determining if it's the wheel or the frame that's askew. And neither the frame nor the wheel (at least, not the dishing of it) was the problem in this case; it was an extra ball inadvertently included in the bearings. -- My email address is antispammed; pull WEEDS if replying via e-mail. Typoes are not a bug, they're a feature. Words processed in a facility that contains nuts. |
#7
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A Muzi wrote:
Premium Grade 25 Chrome Steel balls are dirt cheap and are sold in matched sets. Grade 25 means less than 25 millionths of an inch variance within the lot. (Campagnolo, in metric, says 'uno milionesimo'). Usually around two bucks for all that! Want to see a real example of gouging (following on from the spoke thread below)? http://www.sjscycles.com/store/item3551.htm That's nearly $10 for enough balls to do a rear hub in Grade 100, which are 4 times worse than Campag's. |
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