Warped rear wheel

[dougsr.874]

A customer hired me to transfer a 4 stroke HS kit with a Stage 111 gearbox from and old bike to a new Schwinn 7 speed bike...the old bike had a badly warped rear rim ....I transferred the kit and tested the chain alignment both on a jackstand and also road the new bike several miles.....all appeared ok....customer picked up bike and road it before leaving my shop....all seemed ok....he put it on a bike carrier rack and took it home....an hour later he was back with another very badly warped rear rim........he swears he did not jump any curbs or anything like that.....I'm at a loss as to why this is happening....anyone have any clues.....Please help

 

[grinningremlin]

I'm thinking things like rag joints and wheels sheaves make it impossible to true a wheel while they're on.I assume by your post you mean eggoed, you'd need to remove anything clamped to the spokes then pluck them and probably find a large group are either too tight or loose.Depending on how badly out of round it is you may have to do the old extra grunt trick, loosen up all the spokes a bit find the most egged parts, put one to the floor (cushioned) and the sit or push firmly to round the bends a bit, then true.May also be new wheel time.

 

[dougsr.874]

Details??????...it was a NEW bike with NEW wheels....why would a NEW wheel on a NEw bike warp....

 

[grinningremlin]

u left out all important details. trued or replaced? zero deatails except calling it a bike and a problem. im not interested in idle speculation. either the wheel was good or comprimised. wich is it? .

The post asked for advise, not attitude.Sub, you come off like most LBS workers I've dealt with, a bit dickish.You're not interested in idle speculation, yet find the time to write about it?You could've easily said, "more details about the bikes condition" without all the tude.This ain't a bike shop, don't act as such.

 

[HeadSmess]

warped wheels...

this i just dont get. i can run loose spokes, bent spokes, missing spokes and quite happily hit potholes treeroots dogs and other speed humps at high velocity. sure, i tend to overlook anything less than 5mm of ...hmmm.lies? if its true when straight, all bends must be lies! basically it has to start hitting things before i fix it.

i will true a wheel up with an indicator when i do work on one.

experience taught me that by overdoing the tension, you can make a rim warp... really suddenly, and really badly! there is a limit to the tension.

maybe you give em one extra half turn all round, just in case? if so, dont!

you dont metion how you attached the sprocket. im assuming via ragjoint to impact on the spoke tension.


so. the 7 speed. a hub gear or derailleur? old bike, hub or derailleur?

all wheels are dished when trued cus of the sprocket offset... meaning spokes on other side are steeper. more sprockets, wider cluster, more dish.

could just be that the material you use for your ragjoint doesnt have enough "squish" to compensate for the steep angle of the spokes? so suddenly you try kinking a small section on half the spokes, increase the tension, and well... SPROING!

or you simply overtighten the ragjoint, which seems impossible if the original bolts are used
are you using the original rubber? some of the stuff supplied is far from equal thickness. a "low impact" rubber tile is best. find em at hardwares/decking places etc for kiddy playgrounds.

may be better getting a nylon cone machined up to ride on the spokes under the sprocket?

its the first time ive heard of this. and my first suspicion is always on the owner...

maybe...just maybe...the customer sticks bike on bike rack, drives into garage and forgets about the cupboard just inside the doorway?


ignore sub, hes canadian

 

[grinningremlin]

you call that informative? the question is why would a new rim bend?
you two guys offer nothing but short mastabatory answers on the subject and im trying not to write a book about it. i feel sorry for gremmlin if every person that is employed in lbs are his enemy. thats really awefull for you and people needing service for their bicycle. shame on you all that have posted on this thread. demanding? look at yourself

If you consider everyone who's a bit dickish your enemy, you must have scads of enemies.I said "many" not "all"
I said "a bit dickish" (which you are) not "enemy"; stop being so dramatic Betsy.You replied more than anyone, with less useful info.If it's beneath you, just move on to the next thread and don't reply.

 

[darwin]

My best guess besides the obvious is cheap rims and the rag joint stress on the spokes. Seems some spokes are tighter than others and because of the looser spokes the stress is warping the rim......dunno just what come to mind 1st. Sure is strange his old rim was warped too, maybe he thinks going over curbs is ok, coincidences are rare in my mind.

 

[butterbean]

For an inexperienced rider or mechanic (not saying you are inexperienced, just including it as an example), there are two main possibilities for wheel damage. One is improper rag joint setup. The only way to properly secure the nuts and bolts is to either use lock nuts (nylon inserts grip the threads and prevent loosening) or use an adhesive (I've use loctite and plain old superglue, both work fine). I am sure that you already know these things, but is it possible that the customer messed with something and screwed it up? If the nuts and bolts come loose, they will twist right into the spokes and bend the wheel very badly. The only other possibility I can think of with a NEW wheel is that the customer rode it in conditions it wasnt built for (new schwinn most likely means department store, they aren't built for anything much more than light street use). I had my bike vandalized, and the rear wheel was irrepairably damaged. I found Weinmann DH-39 rear wheels on amazon for $50. They are double walled alloy rims, and I'm ordering one on Thursday.

 

[joshua97]

motorised bike sprocket on left of wheel, uneven power distribution, causes wheel to buckle, u ned h HD wheel, -sprocket mounts to the hub, or a good steel spoked wheel, even weld sprocket to the hub if ya have to, this is normal, just replace it , he sounds like he rides it hard too, cant blame him lol,

 

[joshua97]

ok cool, he should learn to replace wheels