Rear hub spacing
 

I replaced the bearings of a rear hub of an old mountain bike.

After reassembling I am going nuts trying to align the wheel and brakes. It looks like the rim is way off centre, and I don't think it was before.

I wonder if I mixed up the spacers.

Looking at it now, I have the big spacer on the cluster side. You can see it projecting out. Is this normal? Looking at several other bikes around, it seems that there is usually much less clearance between the cluster and the dropout.

So should I swap the spacers left and right?
It'll take me at least half an hour, so I would like some reassurance that I'm on the right track.

Thanks for any comments or suggestions.
http://bikeforums.net/attachment.php...hmentid=243135

You've got the large spacer on the wrong side. The cassette (or cluster, if it's really old) takes up a lot of space. Most hubs put a spacer on the non-drive side to keep things from getting too unsymmetrical. That big spacer on the non-drive side starts to balance the cassette on the drive side.

Do you have cone wrenches? Might be time to call in a professional if you don't.

Thanks, I thought that might be what I'd done.



I've got cone wrenches.
Obviously just was too dumb to remember which way the spacers came off.

I belatedly looked up Barnett's guide and he recommends using wire ties to keep the nuts, cones, spacers in order. I'll be doing that from now on.

Anyway, much cheaper to buy tools and DIY for most repairs, especially for an old bike like this, would cost more than it's worth to get it fixed at a shop.

Unless I'm working on something really complicated, I usually find it's a better idea just to figure out why each part I'm removing is the shape it is, giving me a thorough understanding of the mechanism's function and assembly.

This approach should work for something as tricky as an Ergolever (YMMV), but an STI lever is complicated and obscure enough to pretty much preclude that method for almost anyone... for such things, I try to maintain sub-assemblies and/or take a lot of pics.

It's a good idea to lay the parts out in the order in which you disassemble things.

I did the same thing the first time i took apart my rear hub. I forgot which side it went on, and it seemed logical to go on the cluster side. Had to take it apart and put it where it belonged. Each time you take it apart you'll get that much better at it and will take less time.

A good move to be sure, but a bit fragile if it's your only way of knowing where stuff went.

*bump* Oops : (

+1 If you need to re-assemble a hub "from scratch" it's best to know the actual procedure rather than trying to remember which way things came off. Cup and cone hubs are not that complicated.

For a multispeed freewheel or cassette the last (smallest) cog should be as close to the right dropout as possible without it or the chain interfering with the frame. This way the wheel is dished (I know, I know.. wrong use of dish) as little as possible and the wheel is stronger. Then simply fill up the left side with washers until the spacing of the wheel matches the spacing of the frame.

Note that if you are respacing a hub this way, maybe to use in a different frame or with a different cluster it is necessary to check the dish of the wheel and possibly re-dish it with a spoke wrench.

+1, even though I'm comfortable with most mechanical things I make it a habit to lay a paper towel on a workbench and lay parts down in sequence outside up whenever I disassemble anything I'm not 100% familiar with. Not only is the sequence important, but keeping the outside up is also. I can't count how many times I've taken off what at first glance seems symmetrical only to find later that it isn't.

Having good habits, and sticking to them will keep you out of trouble, and spare you second guessing, doubt and duplicated work.

The easiest strategy is to remove the cone, spacer(s) and locknut(s) from the non-drive side, and leave the drive side assembly intact. As long as you get the cone on the inside and the locknut on the outside you can't get it too wrong.

Edit: also, it makes a lot of sense to set the drive side locknut very tight against the driveside cone and spacers – that way you can adjust bearings by slightly loosening the non-drive side (which is easier to access without removing the freewheel), and simply holding the drive side locknut wile adjusting from the NDS. At least, that’s what works for me.

I think everyone has given some good advice on keeping axle spacers in the right order.

I do actually stock axle spacers and I tend to remove axles and measure fw/cassette side to -MINIMIZE- the space so the chain just has sufficient clearance to shift well, but no space to fall and get wedged between dropout and cog, and and the same time, I add spacers to the non-drive side and then I re-dish the wheel while maintaining the same rear axle width. This reduces the asymmetry of the spokes and makes a slightly stronger wheel without sacrificing shifting or too much in chain alignment with the front chainrings.