Wheel bearing shims/spacers

[daveschile]

Simple little questions here:  A friend of mine installed new wheel bearings in my r65, and I'm not sure its right.  Do the spacers or shims come out of the stack or are they held in place by the seal?  The spacer is protruding on the right side of the wheel (looking forward)  is that how it's suppose to be?  Seems like it should be on the other side (if at protruding at all) because the disk is sitting too close to the fork slider.

Any input is greatly appreciated!

David

[Bob_Roller]

The 'hat' spacers are between the bearing and the grease seal .

They protrude through the grease seal on both sides of the wheel .

Post a picture of what you have .

[montmil]

As the front axle passes through the front wheel and exits the bearing on the brake disc side, there is a thick washer followed by a short, thick tubular spacer.

Yes, the disc is close to the slider but doesn't contact the fork lower. When properly assembled, you should be able to fit the disc between the brake pads without any binding.

Check the micro fiche on most BMW dealers websites for images of the assembly. Baring any disc to brake pad issues, it sounds like your friend has it done correctly.

[daveschile]

Thanks for the replies.  Something just don't look right about the in-bearing spacers.  I checked the fiche but I can't tell how far they are supposed to protrude from the seal.  You can see in these pics that the non-disc side (right) is protruding almost 1/4 inch.  The other side almost not at all.

[Bob_Roller]

On my '81 R65, I have the same amount of spacer showing on each side, like your first photo .

Were you present when the bearings were reinstalled in the wheel ?

Were there two metal tubes / spacers between the two bearings ?

There are different length 'hat' spacers available from BMW, by chance did you notice any difference between the two ?

[daveschile]

Unfortunately, I wasn't there.

I can feel other spacers moving around inside there (within the stack)

Maybe I'm just not installing the axel correctly.  After the wheel, there should be 2 spacers?  I'm only installing one big (maybe 20cm wide) tubular one.  Then the fork, then a washer and nut.  Maybe that washer goes inside the fork?

[Bob_Roller]

The two spacers are inside the wheel between the two bearings .

There's one spacer that goes between the wheel and the left fork tube, the thick washer goes under the axle nut .

[daveschile]

Can one remove the seal and change the top-hat spacers around without having to buy a new seal?  Or do you always need a new seal once you've pulled it?

[Barry]

Can one remove the seal and change the top-hat spacers around without having to buy a new seal?Or do you always need a new seal once you've pulled it?  

You'll get different opinions on this but I can easily get the seals out undamaged and then re-use them.  When I first got my bike, I found the rear wheel in particular had grossly too much pre-load and while I was trying different shims I took the seals out half a dozen times without any problem.  It depends on your technique and the use of either a proper seal removing tool or something that you can devise that works on the same principle. You need something that hooks up under the seal and push up on the steel outer edge of the the seal housing and with a fulcrum on the centre of the bearing. To provide something for the fulcrum to push against I sometimes need to drop a washer or disc in to cover the bearing hole.  

As the previous replies have indicated the seals and top hat spacer have nothing to do with bearing spacing. They are just transferring compression forces from the axle to the bearings. It really doesn't matter at all how much of the top hat spacer protrudes through the seal provided the bearing pre-load is correct.  That's the real issue you should be concerned with.

How was the pre-load checked ?

You'll get different opinions on this too. I'm happy with the shake the wheel test and find it easily accurate to 0.001"

[georgesgiralt]

Hello !
I always have a set of lip seal at hand when I grease my wheel bearings. (at every tire change).
Often I get them out with a very large flat screw driver by prying at the metal cage a very little bit at a time. Buy a new pair and try it. You'll be relaxed as you've new parts if something goes amiss.
The external "spacer" is a thrust washer and a lip seal part. So if they are worn, change them. Also torque the axle nut per spec. Otherwise you'll explode this washer. Don't ask how and why I know...
If properly maintained, these bearings are incredibly resistant. Mines are perfect and 31 years old...

[Barry]

Georges makes a good point that the seals run on the top hat spacer surface making them a wear item.  It also means you can usual see from the wear marks how much of the top hat spacer protruded through the seal if that helps make clear which side they were on.