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Old 09-26-09, 08:52 AM   #1
lineinthewater
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Freewheel moving/warped when tire rotates freely??

So I have my bike upside down and am "free" rotating the rear wheel. The entire freewheel is actually moving (as if it's center is barely rotating around the axle axis). I'm sure this description is confusing. Perhaps this is better: suppose the freewheel is not attached to the wheel. The sprockets are stationary (relative to the center of the freewheel). The entire unit is rotating just slightly around where the skewer comes through ... as if something is warped or something. Is this a problem with the internal freewheel bearings or the freewheel mechanism?? Sorry if my technical terms are not accurate.

Man that description is confusing. Having a hard time explaining this one.

Last edited by lineinthewater; 09-26-09 at 09:14 AM.
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Old 09-26-09, 09:13 AM   #2
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Freewheel(and cassettes too for that matter) can often wobble around a little. For freewheel there are at least two fairly obvious contributors:
1) bearing play is set by shims, so getting it just right isn't that easy. Since a little play during freewheeling isn't hurting performance it's usually tolerated.
2) the thread for the freewheel may not be "perfectly" aligned with the wheel axle. Once again, with negligible impact on performance it's tolerated.
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Old 09-26-09, 09:28 AM   #3
lineinthewater
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Freewheel(and cassettes too for that matter) can often wobble around a little. For freewheel there are at least two fairly obvious contributors:
1) bearing play is set by shims, so getting it just right isn't that easy. Since a little play during freewheeling isn't hurting performance it's usually tolerated.
2) the thread for the freewheel may not be "perfectly" aligned with the wheel axle. Once again, with negligible impact on performance it's tolerated.
Thanks for the thorough reply. Any idea what level of wobbling would be considered non-negligible?
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Old 09-26-09, 09:55 AM   #4
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Originally Posted by lineinthewater View Post
So I have my bike upside down and am "free" rotating the rear wheel. The entire freewheel is actually moving (as if it's center is barely rotating around the axle axis). I'm sure this description is confusing. Perhaps this is better: suppose the freewheel is not attached to the wheel. The sprockets are stationary (relative to the center of the freewheel). The entire unit is rotating just slightly around where the skewer comes through ... as if something is warped or something. Is this a problem with the internal freewheel bearings or the freewheel mechanism?? Sorry if my technical terms are not accurate.

Man that description is confusing. Having a hard time explaining this one.
You have explained it quite well enough as everyone here has seen what you are describing. It's perfectly normal. Almost 100% of freewheels do this to one degree or another from new out of the box.
Put your mind at ease and go ride.
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Old 09-26-09, 10:19 AM   #5
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Any idea what level of wobbling would be considered non-negligible?
Well, I've never had one bad enough for me to consider it worthy of correction. If it's due to thread misalignment there isn't much that can be realistically done about it either.
Eventually you'd worry about it affecting shifting, but I don't believe it's possible to cut the threads that bad.
If it's down to bearing play I'd have a go at reshimming the freewheel if the sprockets would have a sideways wobble of 1.5 mm or so.
The ball bearings and races inside are fairly small/narrow, so I wouldn't be comfortable with too much slop there.
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Old 09-26-09, 10:26 AM   #6
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Eventually you'd worry about it affecting shifting, but I don't believe it's possible to cut the threads that bad.
If it's down to bearing play I'd have a go at reshimming the freewheel if the sprockets would have a sideways wobble of 1.5 mm or so.
The ball bearings and races inside are fairly small/narrow, so I wouldn't be comfortable with too much slop there.
The shifting seems fine to me. Albeit, it is my "beater" bike, so my expectations aren't that high. Just wanted to make sure it isn't going to become a bigger/$$ problem in the near future. Not to mention I figured it was a good opportunity to learn something new - which I did - thanks all! Sounds like if it ain't showing other symptoms, it is probably OK. I don't think there is any major sideways wobble (along chain line) - I'll take a quick look later.

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Old 09-26-09, 10:36 AM   #7
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It is caused primarily by imperfect machining of the internal portions of the hub where the bearing races are eventually pressed in.

If the race on one side ends up off-center...the hub will have a wobble on one side.

If the races on both sides end up off-center...in opposing directions...the hub will have a very noticeable wobby that appears to cover the entire length of the axle.

If the races on both sides end up off-center...in the same direction...the entire hub will appear to rise up...then fall...then rise...etc.

The functionality of the hub is usually unaffected....however:

1. Watch for endplay that won't go away no matter what adjustments you do - indicative of a loose press-in race.

2. Watch for bearing grind in one or more spots no matter what adjustments you make even after initial break-in - indicative of a press-in race that is REALLY off parallel to the opposite race.

Other than that - go ride.

=8-)
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Old 09-27-09, 11:38 AM   #8
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I've cleaned/lubed many a freewheel, and most all of them "wobbled". Some more, some less. As long as it doesn't cause the bike to spontaneously shift, I wouldn't worry about it.
Although, this week I pulled apart a newer Shimano freewheel that defied reassembly with my tried and true method. Finally figured out the inner bearing race was a different design than those I'm used to.
Most have a simple curved race surface - the inner body can be inserted with plenty of clearance into the cog-carrying outer body. The bearings are held by grease in the outer body race.
This one was so tight, the inner body would not clear the bearings during insertion. That's because the inner body race surface was indented - it had a definite groove that the balls ran in. So, the balls had to be held in that inner body groove to allow the assembly to fit into the outer body. Also, the clearance between the two was much closer. Didn't think of it at the time, but that freewheel didn't wobble. Probably due to that tigher clearance - the outer body and cogs just can't move laterally that much. I surmise Shimano figured out how to reduce wobble and increase index shifting precision by altering design. P.S. - that Shimano freewheel was made in Singapore.
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