Front wheel bearings 1985

[Isamemon]

Need to replacve the sealed front wheel bearings on a 85 R80 RT, alloy wheels
Snobums site does not go into bearings after 84 when they changed to the sealed bearing
the clyumer book ssys ....use special BMW tool.....
is this true
is there another tool that will do it

it also says to heat the hub and cool the bearing

Ive done plenty of the pre 84 ones, the old tapered ones

so any advice is good, thanks

[PGlaves]

The sealed ones go in and out on the Airheads as on the K bikes and Oilheads.

You will need a puller and do need to heat the hub.

I have done it by heating the hub and using a slide hammer with internal hooks that fit inside the race. The better way is to use an internally expanding puller that rests on the wheel hub and applies pulling pressure.

As with most things there is an easy way and a hard way. The easy way is to attach the puller and apply some, but not a lot, of pressure. Then using a circular motion around the hub, heat the hub with a heat gun. When it is warm enough you will hear a little "pop" as the pressure causes the bearing to slip a little bit when the hub is warm enough to expand enough to release the bearing.

Then a few turns on the puller handle extracts the bearing very nicely.

By the book you are supposed to heat to 200 degrees. You can almost do this with boiling water and rags packed around the hub - but it sure makes a mess.

Heat gun and puller ist he way to go - or heat gun and slide hammer if you have to do it that way - but I prefer not banging on things if I don't have to.

I got a good puller at Harbor Freight by the way. And no I don't remember the part number or any of that stuff. I got it because it looked like it would work, and when I tried it it did.

[04R1150RS]

yes but how do set the correct preload on the bearing when reinstalling. There is a distance piece that needs to be used, or can you just reuse the old one???

[PGlaves]

The closest thing in my direct experience are the wheel bearings on the K75 that I put 370,000 miles on. But the hubs are essentially the same as on the late model Airheads with sealed bearings. The bearing part numbers are the same.

I replaced the wheel bearings on that bike at about 80,000 mile intervals by removing the old bearing, installing the new bearing, and always torquing the axle nut to the specified 24 ft. lbs. I never disturbed or replaced the part BMW calls the "Pipe" which is the inner separator that keeps the inner races spaced. BMW lists that as a single part number (one length) and offers no shims.

Since these are deep grooved ball bearings they are not intricate to preload like tapered roller bearings are. My conclusion is that BMW figured that any differences in the race widths due to manufacturing tolerances were within the tolerances in the internal clearances of the bearings - thus grinding and filing the pipe like with the earlier bearings was/is not required.

My Haynes manuals for early K bikes and for Airheads after '85 don't specify doing anything with the pipe except being sure not to omit it if it was removed.

[04R1150RS]

I was referring to the tapered bearings on an '84 G/S, not knowing about the prload is keeping me from doing it and possibly having the dealer do it....as much $$$$ as I hate to. I've done plenty of wheel bearings in cars and bicycles, but was wondering about the G/S's...

Thanks

[bobh41]

Would it be advisable or useful to just arbitrarily replace the wheel bearings? My sense is that if it involves removing them to "examine" them - then why not simply replace them with new? Cost is relatively insignificant.

[PGlaves]

I was referring to the tapered bearings on an '84 G/S, not knowing about the prload is keeping me from doing it and possibly having the dealer do it....as much $$$$ as I hate to. I've done plenty of wheel bearings in cars and bicycles, but was wondering about the G/S's...

Thanks

The roller bearings pre 1985 are a different animal. I don't know the month but Matt Parkhouse did a good article in the ON on those wheel bearings. All my issues except the most recent are in Kansas so I can't help with when it was. Maybe somebody else can.

[PGlaves]

Would it be advisable or useful to just arbitrarily replace the wheel bearings? My sense is that if it involves removing them to "examine" them - then why not simply replace them with new? Cost is relatively insignificant.

Again one answer applies to the roller bearings and a different answer applies to the sealed ball bearings. The older style roller bearings need to be removed, cleaned and greased peridocially. But the hardest part to remove - the outer race - stays in place in the wheel during this operation. If upon inspection the bearing needs to be replaced then the outer race needs to be pulled so the whole bearing is replaced with the new one.

You really can't tell much more about the sealed ball bearings once they are out than you can with them still in the wheel. Since they are sealed and not designed to come apart like tapered roller bearings there isn't much of anything to see.

I manually rotate the bearings when I have a wheel off. Any audible or tactile gritchiness (tech term) or roughness means it is time to replace it.

And one other cardinal rule about wheel bearings:

If it is an unsealed roller type and there isn't a little smear of grease around the axle - the bearing is probably getting dry and needs to be regreased

and

If it is a sealed ball bearing type and there IS a smear of grease around the axle, the seal is probably leaking and the bearing is going to fail pretty soon.