Singlespeed & Fixed Gear - wheel trues blues

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comradehoser
01-26-06, 10:29 PM
please move this to the bike mech forum if you think it belongs there.
the situation: building myself a fixie on the cheap (negative budget); thought I'd splurge and get a $75 pre-built wheel at the LBS--basic Suzue flip-flop hub, old-school weinmann alu. rim. grabbed it on the way back to the LBS to scope the chain line for a new BB, I heard the spokes ping, and being the genius I am, said, aha, needs detensioning. Grabbed the rim the way I thought I remembered a bike mech show me, pulled up on side, down on the other. Result: instant detensioning and a beautiful S-curve sine wave all along the rim. and a little hop to boot.
Here's how I've spent my spare time the last couple of days: oil nipples, true wheel, detension spokes (gently, the right way), admire noodle-shaped rim, cry, repeat. even tried backing off all the nipples and building even tension up from there.
can somebody please suggest an end to the cycle of lameness? bad hub? bad rim? re-build? take it back to the lbs? is this normal?
pings don't necessarily mean that it was overtensioned, it probably wasn't stress relieved, and it woulda been fine had you just retrued it. It sounds like the rim might just be toast at this point.
comradehoser
01-26-06, 11:25 PM
yeah, stress relief. that's what I meant by detensioning. letting the spokes untwist and settle, basically.
I should add I didn't really reef on the wheel. The bending came with not a lot of effort. Kind of surprised me, actually.
fixedpip
01-27-06, 03:12 AM
I should add I didn't really reef on the wheel. The bending came with not a lot of effort. Kind of surprised me, actually.
Sorry to hear of your pain.
As none of us saw what you did to the wheel, its hard to tell what caused the rim to bend. If you really didn't use a lot of force, go and talk to the LBS as it looks like either:
1) Poor build - they never brought the spokes up to tension properly.
2) Faulty rim - but even poor rims take should take a decent amount of force to bend
I would talk to them and see if they can help you out. They may at least give you a free build if you pay for the parts. However as you've messed with the wheel build they may not feel like they're at fault here.
mattface
01-27-06, 05:52 AM
**** I put my axel on the floor, and push down on it with good force all the way around on both sides to stress releive the spokes, and it didn't go out of true by more than a mm. It sounds to me like the spoke tension was way outta whack on that rim.
On a properly tensioned rim you shouldn't be able to do anything like that without a crash-like force. That's my opinion anyway.
Aeroplane
01-27-06, 06:50 AM
On a properly tensioned rim you shouldn't be able to do anything like that without a crash-like force. That's my opinion anyway.
+1. A wheel should be able to withstand a constant (non-jarring) force that you can apply with your hands. I destress the spokes by using a wrench to bend them slightly around each other where they weave in the 3x pattern, and squeeze pairs together during the truing stage. No problems yet.
To stress relieve with ease, grab a sturdy stool with a hard seat (wooden or metal), put the axle in the center of the seat, press down on each side of the wheel around the radius about 4 or 5 times. If you hear any pings, it's time to put it back in the stand and retrue. If you don't hear anything and the wheel was true when you pulled it out of the stand, you're golden! We have an old wooden stool in the shop that has clearly been used 100s of times for this exact purpose..
comradehoser
01-27-06, 08:36 AM
ahhhh... now that's what I remember, see?
I'd trued a wheel before, and I remember seeing the mech and then putting some pretty serious pressure on it myself to stress relieve. the fact that the weinmann just "flopped" into pretzel-like form really took me aback.
I'll talk to the LBS, and hopefully they can fix this sad sadness.
comradehoser
01-30-06, 12:52 PM
actually, I took the wheel apart, bent the rim back into shape, and relaced it with a cool 3-leading/3-trailing pattern you can see here: http://www.terminalvelocity.demon.co.uk/WheelBuild/
seriously easy and fun. looks the snazz.
it was definitely the crap rim that was the problem. I put some *serious* weight onto it in bending it back into shape, and what I used to stress relieve it was nowhere near what was necessary to bend it.
the only thing that worries me is I bent some spokes lacing the wheel up (minor?) and some hub eyelets were a bit deformed and dimpled where the spoke elbows passed over them (major?).
Aeroplane
01-30-06, 01:07 PM
It's not recommended to lace up a hub with a different lacing pattern than it has been before. You might be pushing the envelope.
Bending spokes is fine, as long as they aren't creased.
dolface
01-30-06, 03:04 PM
It's not recommended to lace up a hub with a different lacing pattern than it has been before. You might be pushing the envelope.
Bending spokes is fine, as long as they aren't creased.
true, but it sounds like the wheel wasn't ridden before he re-laced it, so presumably the spokes hadn't bedded into the flanges yet.
he should be ok...
comradehoser
01-30-06, 03:50 PM
true, I haven't ridden it, nor has it ever been ridden to my knowledge.
but the flange is the cheapy-est suzue, and it does have a bit of dimpling in the hub eyelets, particularly on the ones where the spoke elbows exited on the exterior of the flange.
bad? good? please tell me I can do the re-lace, because if not, I'm going to have tears. Actually, I will probably have to wrestle with the LBS, and they are good folks, so I don't want to do that. And lacing wheels, while fun, is not something I want to do twice, especially for plain-jane cross-3.
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