Bicycle Mechanics - Freewheel not parallel to hub?!
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07-23-07, 11:13 AM
After putting a recently purchased Thrift Store 10-speed on the stand I noticed that when I spin the rear wheel forward, the freewheel rocks back and forth about an 1/8th of an inch as it coasts. Thinking this was a bearing issue, I popped the freewheel off and replaced the wheel bearings, but the problem remained. I swapped freewheels with one I had laying around and the problem is still there. The wheel is true and spins just fine. The threads for the freewheel must not be exactly in the same axis as the axle. I'm pretty sure the answer is that the hub is bad but I've never seen this before. Does anyone have any ideas before I pitch the hub? (The thought that this is why the bike was in the thrift store HAS entered my mind, but a new rear wheel is no big deal!)
07-23-07, 11:19 AM
Wobble is pretty common, and I don't think 1/8" is a problem.
07-23-07, 12:10 PM
The gears are slightly angled to improve shifting performance, so when it spins it looks like it's wobbling. That's probably what you're seeing.
07-23-07, 12:13 PM
Well, I'll take a look at a couple of other bikes I've got and see what they look like. This wobbles enough that I can see the pedals twitch.
07-23-07, 02:05 PM
I think your initial post was confusing. The first couple of responses referred to watching the freewheel in relation to the hub body/rear wheel. That is to say, if you hold the wheel still and spin the freewheel, it wobbles slightly outward and back in, away from and back toward the hub itself. This is very common with freehubs, and to some degree with freewheels as well.
But based on your second post, you're spinning the wheel so that the freewheel should remain still while the wheel spins, and yet the freewheel moves a bit and pulls the chain slightly. Correct? If so, you probably just need to lube the freewheel so that its pawls engage and release as crisply as possible. Do a search on lubing a freewheel and you'll find plenty of recommendations and procedures.
07-23-07, 02:17 PM
I think the first two responses got it. When I spin the rear wheel the freewheel wobbles. I rinsed the freewheel with solvent and lubed it so it is operating smoothly. The sprockets don't creep or rotate forward, they wobble in relation to to rim and hub. The wobble is enough that it moves the chain back and forth making the pedals twitch. This makes the wobble seem excessive to me.
07-23-07, 04:25 PM
Not unusual on cheap bikes. Typically the hub flange is not at perfect right angle all the way around to the axle. Don't know if they sitll make them this way, but on the old really cheap bikes with 3 piece hubs the flanges sometimes actually broke free of the hub tunnel portion. Usually not a problem but can make for a noisier drive train and compromise shifting somewhat as well. There is not fix, unless a bent axle is part of the problem.
Very common, probably typical on all freewheels. Don't worry about it.
Wobble is normal; it comes from the slight space in the two bearing sets rotating around as the freewheel revolves.
07-23-07, 07:40 PM
...or a bent axle...
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