Rear wheel wobble! Need advice ASAP
 

Hello all,

I am currently in Guadalajara on a trip down to Buenos Aires. I've noticed that I have some fairly bad wheel wobble at the moment. This is even with the bike on the center stand, and pulling on the throttle just a little bit. I had a new tire put on recently and a new sprocket carrier bearing put on. Could the tire not be balanced properly? Maybe the bearing too? I checked the rear wheel bearing and its pretty tight. Im hoping that maybe the rear wheel may need to be replaced but i dont know. Please give me your feedback!!

thanks,

Ben

Ben, sorry but I'm a little confused!

Wheel wobble can mean several things. Please clarify:

1. you say on the stand and throttle pulled - huh?

2. wobble does not mean balance - unless there's something weird!

Here's some thoughts

a. When RIDING the bike do you notice anything at all?

b. When on centerstand, engine off, and spinning the wheel do you SEE anything, movement, anything other than perfect smooth spin?

c. check the spokes - are they all evenly tight? Bang each one with a small wrench and you just get a nice tone. They should all sound the same. Any dull "tonks" means a loose spoke, MANY of those and the wheel needs to be repaired asap or it WILL collapse! I'd recommend taking the wheel off and take it to a bike shop.

d. the wheel does NOT need to be replaced, it's ll repairable-probably.

But we need to isolate the issue clearly.

If a visual issue of movement, it's either:
wheel bearings - you said "pretty tight" - ack! It must be perfect! NO looseness at all, and spin smoothly.
improper assembly - probably missing spacer
loose spokes - see above

If you FEEL it while riding, and visually on the centerstand it's perfect, no wiggle/wobble and bearings are tight, it's wheel balance.

let us know!

Hey Grant,

So my friends riding with me noticed that the sprocket and the hub is not spinning true. This what I meant by the wobble. I noticed that it was not riding as smooth as it usually does.

When I put the bike up on center stand and spin the tire I DONT notice that the tire is spinning wrong. However, when the bike is turned on and put into first I noticed that sprocket/hub is not true. I checked to see if the chain adjusters on both side were perfect, they were a little off. When I fixed it and tightened the axle bolt really hard it helped a bit. I wonder if there is something wrong with my sprocket? I wonder if the guy who installed the sprocket carrier bearing installed it improperly.

I took a small wrench to the spokes and found a few that sounded unlike the others. Could these few loose spokes cause all of this?

In regards to my wheel bearing, I think tight is not the right word. I think the wheel bearing is not spinning very smooth. Not like the new sprocket bearing.

I also held a small wrench a mm from the wheel and noticed that it touched in a few places. I am pretty sure that the wheel spaces are installed properly. They have broken into two, but it has been like for a while without any problems.

So does this conclude that my tire is balanced and that the issue is either in my sprocket/wheel?

Thanks for you input Grant!!!

-Ben

Is the area clean? Because you are going to be working on it.


If only the sprocket has the significant wobble then it is probably an assembly problem with the sprocket (and possibly its mounting assembly). Take off the rear wheel, while removing the sprocket with any carrier look carefully for any misalignment. When disassembled examine for ware. Reassemble with care.

The roughness of the wheel bearing is probably unrelated. But it does indicate that it should be replaced! Particularly if you are in a place that can do such a thing now.

As long as the wheel and tire spins reasonably "smooth" - in other words no more than 3-5 mm out of round - it's all good. You won't feel that amount of out-of-round. Up to 6-8mm is ok for off-road though of course not "good" it's "ok".

'Really hard" isn't necessary! A 30 cm long wrench with good force is plenty.

The sprocket and hub should spin quite true, they are mounted on a bearing!

It's possible this was damaged, (though really hard!) or the bearing has failed.

NO! They have nothing to do with the sprocket / hubb. talk ot a bike shop about getting the spokes tightened properly.

As warin said, this is bad, and should be repaired asap.

yes-ish. wheel balance is WEIGHT, not mechanical measurements or adjustments. The wheel could be out of balance, but irrelevant to this issue.

Spacers broken in two - sounds BAD! Again, check with a bike shop - I'd want to know WHY they're broken!

good luck!

You do want to get this fixed.

If nothing else the sprocket wobble will ware the chain. :(

The bearing could fail - leading to seizure. :funmeterno:

So I just returned from a Beemer shop in Guadalajara. The main problem was that my rubber spacers that fit into the hub were installed improperly. I think that this was my fault. We fixed that and still noticed a slight wobble. However, it has been reduced significantly, but its not perfect.

In regards to the wheel bearing, the mechanic said it was fine. They also said it was not entirely necessary to replace the rubber spacers. They did not have any new ones at the shop so I will try to grab some up in another city later on.

I am not 100% satisfied but it is gonna have to do for now. I really appreciate your input on this situation. Thanks guys!!!

That will be your cush drive rubbers, in English at least.
http://en.wikipedia.org/wiki/Cush_drive

Take care when you do things for the first time, or where you have not done them for a while. You need to remember how things were placed .. perhaps take a few photos as a guide for reassembly.

Cush drive rubbers ware. You may not find ready replacements. I've used silastic (RTV 732 but really any of these products would do) to make 'repairs' to these rubbers with some success. But take your time and do it right. The rubbers sit into something, a thin grease coating on that something before using the silastic will make removal easier. The silastic is used together with the worn rubbers - not as a total replacement. You use the fitting to form the silastic into the right shape. Leave the fresh silastic for say 24 hours before use to let the silastic set.