How much vertical wobble is acceptable in rear sprocket

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Motorbikenewb

New Member
Mar 19, 2013
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Columbus, OH
Greetings fellow Motorbicyclists,

So, my 3rd build is complete, but I haven't started it yet. I did my best to make sure the 44 tooth rear wheel sprocket was centered when I mounted it. But during the process of tightening the bolts it came off centered by about maybe 30 - 35% or so.

As a result it wobbles a bit on the vertical axis. It also wobbles some on the horizontal axis, but I'm using a #41 heavy duty chain I got from the tractor supply store. Its very strong and much wider than the stock chain, so it more than accommodates for the slight horizontal wobble.

However, the vertical wobble causes the chain to go from moderately tight to moderately loose with each rotation of the wheel (due to it being a bit off centered).

I know the chain will stretch with use, and for all I know, my situation may not be a serious problem. So I just wanted to ask everyone if they encountered this situation and what are the chances of my having to do rework (take of rear wheel and center the sprocket).

Am I good to go or can this turn into something bigger?

Thanks in advance.

.flg.
 
timboellner

timboellner

Member
Apr 1, 2009
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Towson Maryland
You're looking at a potentially dangerous situation unless you take the time and effort to fix something you know in your own mind isn't right.

Chain alignment and proper tension is essential.

Your loose, then tight situation will prohibit you from ever getting an even amount of tension on the chain. It will always have a too loose spot and a too tight spot. You'll be pitching the chain off while you're riding.
If your chain ever did a "bunch and munch" locking the rear wheel up you'll never forget it .
These bikes are a lot of fun but never underestimate the potential for your own serious injury. Trust me... do all you can to make your bike as reliable and safe as you are capable of it being.

Do it right or do it twice.
TiM
 
2door

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
Ditto, ditto, ditto:
Please listen to the man's advice and get that rear sprocket centered and wobble free.
Trying to ride a motorized bicycle with a sprocket mounted like you describe is asking for trouble. At the very least you can damage parts, rims, chain, engine, etc and at the worst end up with serious injuries.
There are numerous discussions here on the forum as to how to get the sprocket mounted correctly. Take a little time and do some reading before riding the bike as it is.

Tom
 
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Motorbikenewb

New Member
Mar 19, 2013
52
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Columbus, OH
Cool... thanks for the response. Regarding the rework, can I reuse that rag joint or will I need a new one? Perhaps flip the rubber around? I've never had to do this piece of rework before... just curious.

Thanks.
 
2door

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
Yes, you can reuse the same parts. You don't even have to flip the rubber.

Here's a hint: Once you have the sprocket and parts all assembled and while it is still loose on the spokes, suspend the wheel in the frame and spin it. Watch to see which way it needs to go then use a soft head hammer or a block of wood to gently tap the sprocket teeth in the direction it needs. Keep checking and tapping as you tighten the bolts. many of us use a easily made pointer to use as a guide. A coathanger wire works well. Temporarily attached to a fixed point on the frame to use as a reference to the sprocket.

If you have a side to side wobble you can adjust that by the bolts but make sure you don't have a warped sprocket. That isn't common but it does happen. If the sprocket is warped you'll need to flatten it. I've also seen the rubber parts that had been cut at an angle. That will throw things off too. Both rubbers need to be consistent thickness across their full surface.

Tom
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
^^2door nailed it. Tap and tighten slowly and carefully. It's not that hard to get it perfect if you're patient while tightening.
Making a sleeve to take up slop in the hole can help too.
I've used a strip of aluminum can wrapped around the hub to center things exactly on the hub. Just cut a thin strip the length you need to wrap around the lip on the hub which removes all the play in the center hole so it centers perfectly true.
 
Last edited:
Msiert

Msiert

Member
Sep 19, 2014
56
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Omaha NE.
Sorry for posting in a dead thread but been searching all night for an answer to a vertical wobble in my rear sprocket . What is throwing me is I have a claim shell hub adapter....how can those get a vertical wobble?

How can I fix it?
 
Kioshk

Kioshk

Active Member
Oct 21, 2012
1,152
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Connecticut
Post some pics of it in a new thread. You sure the parts are true? Those adapters are well machined as a rule; sounds like your hub-wall is off. What diameter? (put it all in a new thread; this one's related to a rag-joint adaptation).
 
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