EXTRACTING WHEEL BEARINGS


An Answer from Tim Bond, followed by A Comment from Brian Curry


Subject: BMW: Wheel Bearings
Date: Fri, 26 Dec 1997
From: WireWheels <WireWheels@aol.com>
Prez Bob sez:
> I need some help. I'm going to (since it's raining and I can't ride today)
> clean and grease my wheel bearings on my 1980R100T. It says in my
> copy of Haynes to: heat the wheel to 176 degrees in order to draw out
> the bearings. Ok ... how does one heat the wheel to this temp? I can
> think of lots of wierd ways to do this but nothing practical comes to mind

On spoked /5 wheels you heat the hub with a propane torch until your spit bubbles, and press/drift the bearing cluster out with the axle. Not needed on your snowflakes, if that's what you're running.

Pop the top hat spacers out of the grease seals and note if they are of different widths. Should be the same, but... Put a big screwdriver under the seals to pop them out and the bearings will fall out. Put them back on the same side to match the races! Just place the bearings in left/right format while cleaning and you'll be OK.

Note that there is a small spacer that sits in the long spacer that will fall out when you pull the first bearing. This spacer controls the bearing preload. Don't lose it! You'll see where it sets in the long spacer.

I have two of those RT's and can't remember if I'm telling you right but that's how most work =8-O

I've used a very black moly grease for years on wheel bearings and most everything else. EP and waterproof. Don't get too excited spooging the grease on your palm when packing the bearings or you may drop them :)

Tip! After you bolt the wheel on the bike, spin the wheel and feel the fork slider for vibrations. This should be done beforehand but is a good telltale for bad spots and to see whether you've done some good.

Also, lacking the spacer to put on your axle to check the bearing preload that the little spacer controls, check for any slop when you push/pull the wheel towards the forks. There should be no slop and the wheel should spin freely with brake calipers off.

That spacer can be obtained from Ed Korn or you can whip it up with a chunk of EMT conduit, but it won't be true unless spun out on a lathe.

Torque the axle nut to spec all the time as tapered roller bearing preload is important!

I've seen Harley riders adjust the chain and torque up that BIG axle nut and crush the wimpy bearing spacer. After a mile their bearings are smoking and seized up and the wheel is trash now that the races no longer fit in the wheel. BMW's have the adjustable spacing. H-D's do NOT!

Enough ranting. I'm going to correct some more wheels... Good luck!

  _______________________________________________

  Tim(Bondo)Bond        606-873-6686        3455 Oregon Rd
  Wire Wheels MC Svc                     Versailles, KY 40383
  http://ourworld.compuserve.com/homepages/WireWheels
  WireWheels@compuserve.com     WireWheels@aol.com
  _______________________________________________

Subject: BMW: Wheel Bearings
Date: Fri, 26 Dec 1997
From: Brian Curry <bmwbrian@voicenet.com>
WireWheels wrote:
> Put a big screwdriver under the
> seals to pop them out and the bearings will fall out.

They shouldn't. The bearing outer race should be a heat shrink fit. That is why you heat the hub. I remove the seals and then use a chunk of handlebar as a spacer to clamp them using the axle and big axle nut. Then heat the hub, and tap or softly drive them out.

> Note that there is a small spacer that sits in the long spacer that will
> fall out when you pull the first bearing. This spacer controls the bearing
> preload. Don't lose it! You'll see where it sets in the long spacer.

The BMW parts have a small "changeable" ring on the inner spacer. After market (Lesters") do not. You have to make the ID or OD shorter by carefully flat sanding.

> Tip! After you bolt the wheel on the bike, spin the wheel and feel the fork
> slider for vibrations. This should be done beforehand but is a good telltale
> for bad spots and to see whether you've done some good.

If you use the axle and handlebar method, you can check the rear bearings before reinstalling. On the front, with disk brakes, you have to preload it in the wheel. :(:( (Tapered rollers in disk brake models are PITA.)

> Torque the axle nut to spec all the time as tapered roller bearing preload
> is important!

Yup. Make sure it is right.


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