In preparation for the upcoming riding season, my thoughts turn to wheel bearing preventative maintenance. Truth is, I don't recall when - if ever - I had the wheel bearings changed on my 1983 R100RS. I inspect them when I replace tires, but I've never found them to be rough or suspect in the many years and miles I've enjoyed this machine. It must be time to change them out, no matter what they feel like. (I think BMW recommends their replacement at 25 k miles.) I generally do my own maintenance, but I cannot find any on-line or printed info that explains to my satisfaction what must be done. YouTube videos address earlier BMWs, as far as I know. Is wheel bearing replacement on the 1983 models of R100 so delicate that a shade tree mechanic should not attempt it?
If you'll calculate the RPM of the wheel bearings at 100 MPH (a speed you'll agree is ridiculously uncommon) you'll see that it's running quite a bit slower than a normal 1725 RPM electric motor... and those run for decades on cheaper bearings. So changing the bearings is unnecessary, and involves a lot of measurements and shimming you can't do.
What you DO need to do is refresh the bearing grease. That only requires removing the seals and pumping in new grease. Try that instead.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Okay, I get that the bearings, if not abused, will outlast the rider.
The issue I'm wrestling with is the preload adjustment. Bike is a 1983 model, so I'm assuming that the hub has a cast-in shouldered steel sleeve. This seems to simplify setting up the assembly. But, doubts remain. If I remove the bearings, clean and re-grease them, can I be confident that I can just install all the original bits (with new dust seals, of course) and achieve the proper bearing preload?
I've read the noted guru's method of measuring preload with a string and, quite frankly, I'm left completely baffled by it.
ABC632, have a look at the info here. I had a spun race in my rear snowflake. I wouldn't have know anything about it without reading through this, and the info linked within. It sounds like your wheels are in good shape, but as my wise ol high school janitor used to say, "the more you know, the more you know"
Thanks for that! Lots of info to wade through there.
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