Bicycle Mechanics - diagnose a wheel

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kyselad
11-10-07, 05:59 AM
I've been tasked with fixing my lady's wheel, but I'm trying to figure out what's wrong with it before making it worse. It's seriously (easily a full cm) out of true right where 2 adjacent spokes (adjacent on the hub, not the rim) are badly bent, and the bent spokes are basically under zero tension. What's got me stumped is the rim -- it's pulled towards the hub with the loose spokes at the point where they connect, whereas I figured it would pull away from that hub.

Perhaps the biggest problem here is we don't know what happened to her bike. Seems likely someone drove a car into it while it was locked up, but it's hard to be certain exactly how the damage was done.

One more observation -- the bent spokes straddle the seam in the rim. I looked for cracks and didn't see anything, but maybe this is important? Or maybe it's just a coincidence.

Any thoughts on how to proceed? Are the spokes/nipples toast? Does the rim need to be banged out flat(ish) before I try to get it true/round? Is the rim a loss? Thanks for any advice. BTW, I've built and trued wheels in the past, but never had to fix a seriously damaged wheel.

HillRider
11-10-07, 06:40 AM
If the rim is displaced inward radially, it is obviously bent. The spokes are loose because of the damaged rim, not the other way around.

Getting the wheel round again will require unlacing the whole thing and pounding the rim out but it will still be compromised for both roundness and strength and may never be satisfactory. The cost to do this isn't worth the time or money.

My recommendation: buy a new wheel.
Retro Grouch
11-10-07, 06:46 AM
If the rim is displaced inward radially, it is obviously bent. The spokes are loose because of the damaged rim, not the other way around.

Getting the wheel round again will require unlacing the whole thing and pounding the rim out but it will still be compromised for both roundness and strength and may never be satisfactory. The cost to do this isn't worth the time or money.

My recommendation: buy a new wheel.

+1. Sorry.

wroomwroomoops
11-10-07, 07:07 AM
That rim is probably dangerously stressed, and relacing it won't fix the structural damage it has been subjected to. Any wheel built with that rim would be unsafe.

There isn't much salvatgeable from your wheel, I'm afraid, eccept maybe the hub, but some scholars suggest that relacing a used hub isn't the greatest idea, either, because of the deformations in the spokeholes/flanges. I tend to reuse my hubs, but I am only 64 Kg (or less, depending on the season).
kyselad
11-10-07, 01:52 PM
Okay, time for a new rim I guess. I'm a fan of recycled hubs, so I'll see if I can carve out the time to lace up a new rim. If memory serves correctly, it's probably just worth buying a whole wheel. But where's the fun in that?

Thanks for the input.
wroomwroomoops
11-10-07, 02:19 PM
Okay, time for a new rim I guess. I'm a fan of recycled hubs, so I'll see if I can carve out the time to lace up a new rim.

You have my approval my friend. Godspeed!
operator
11-10-07, 02:20 PM
Okay, time for a new rim I guess. I'm a fan of recycled hubs, so I'll see if I can carve out the time to lace up a new rim. If memory serves correctly, it's probably just worth buying a whole wheel. But where's the fun in that?

Thanks for the input.

If you can find the exact same rim and have the tools/time to do all the labour yourself - it might be worth it.

If it's a front, probably not worth it, rear maybe. Fronts can be had for $30-$40. Not **** wheels, shimano.