wheel bearings

[Rob Frankham]

Mole Wrench or Mole Grips = Vise Grips.

For many years in the UK, Vise grips were made by a company called Mole and it is now a generic name for that type of tool.

Rob

[Deleted User 62]

Mole wrench?
Is that a surgical tool?

Nope, Lawn and Garden...

[twist]

I just did the bearing and race replacement on a set of snowflake wheels. I found the replacement to be pretty easy. On problem tho, when I reassembled the rear wheel, in exactly the same order ans removal, the bearing on the Left side (opposite the brake side) doesn't sit all the way in the new race. When the dust cove is installed it can't be pushed down flat and flush with the outside surface of the hub. Is this normal until it gets installed on the bike? Once tightened to the swingarm, will that provide the preload?

[ME 109]

No it aint normal, make sure the outer outer shells are all the way into the hub.
Don't use the axle nut to seat the bearing shells!!
Use an old shell, cut through on one side (clean up cut) use this shell to drive new shells in fully.
The 'cut' shell will be easy to remove.

[twist]

that bearing race is seated all the way, it's the "wedding ring" keeping the bearing from sitting all the way into the race. I put it back together with the same parts that came out, the exact sequence. Is it possible the replacement bearings are that much different? (BMW bearings)

[twist]

I got the handy calipers out and discovered that the replacement bearings are about 1/100 different. the old bearings are .48 and the new bearings are .49. That would do it I think.

[Ken in Oklahoma]

that bearing race is seated all the way, it's the "wedding ring" keeping the bearing from sitting all the way into the race. I put it back together with the same parts that came out, the exact sequence. Is it possible the replacement bearings are that much different? (BMW bearings)

I got the handy calipers out and discovered that the replacement bearings are about 1/100 different. the old bearings are .48 and the new bearings are .49. That would do it I think.

Twist, how do you know that the bearing outer races are seated all the way in the hub? Did you take the one out and reseat it? As ME109 said, it’s essential that the outer races be square with the hub and seated all the way. Did you heat the hub and chill the outer race before installing? ME109's technique of taking the old race, cutting a slit all the way through one side, and then using it to drive the new outer race into the hub is an excellent idea. I’ve done that to good effect and the driver is free.

As for consistency, you should expect the new and old bearings to be very consistent with each other. As I think I may have said earlier in this thread, I have found the bearings to be so consistent that as often as not I won’t have to change the wedding band to get the correct preload.

And what is it that you're measuring? It can't be the outer races can it, because they're already in the hub I thought. Are you measuring the width of the inner races? If so I I wouldn’t necessarily be concerned. It would all depend on how the preloading of the bearings comes out.

And what kind of calipers are you measuring it with? Dial calipers, vernier calipers, or digital calipers should give you three digit resolution, not two digit resolution as you reported. That much ambiguity makes me nervous. A difference of 1/100 or 10 thousandths is a lot of difference. I don’t think I’ve ever experienced more than a couple thousandths difference between the old and new wedding band that was required to get the preload right.

I don’t want to sound like I’m coming down on you. My goal is to emphasize the need to get it right. And here on boxerworks is a good place to learn. I and others will gladly type lots of words to help you get it. When I finally got it, it was a forehead slapper. And when you do get it, it will stick with you.

Have you reviewed Duane’s article on bearings? There’s a lot of good stuff there.



Ken

[twist]

OK, so what I'm trying to say is the bearing itself isn't contacting the "cup" or "race" with the "wedding ring" in place. I can tell because without the dust cover I can see that the bearing is sitting on the "wedding ring" and not in contact with the race cup at all.

When I used the digital caliper it gave me a reading of .48 hundredths of an inch for the old bearings and .49 hundredths of an in for the new. Measuring the bearing itself, the depth of the bearing. The race is fully seated in the hub. It was done by heating the hub and freezing the race. When the race was inserted into the hub it fell into place and then needed to be seated slightly after it touched the hot hub using a socket nearly the same diamiter and a plastic mallit to tap it home.

If the race was not seated, the bearing would sit in it just fine. As I said before, the inner pipe is in contact with the "wedding ring", the "wedding ring" is in contact with the back of the bearing keeping it from fully seating into the race. I don't mean to be a dumb ass and am using the terms used in the book itself. I am 100% certain the race is fully seated into the hub. I am also 100% certain the the new bearing is slightly larger than the bearing I took out. All I need is a "wedding ring" slightly smaller, thinner. Maybe I have the sequence wrong but I put it back together exactly the way it came out, everything is the same but for the bearing. I thought they would be the same exact size too but there is a difference.

[twist]

I have to have the thing wrong as the bearing fits perfectly without the "wedding ring" and the new bearing can't be THAT different! The tube in the center of the wheel seems to be wrong. Not sure how that can be since it is the one I took out. Something is clearly not right though. I think that if the races were not all the way in the hub, the pipe in the center wouldn't seem to be too long. This is a wright buggers muddle and I'm the air head here!

[Ken in Oklahoma]

I have to have the thing wrong as the bearing fits perfectly without the "wedding ring" and the new bearing can't be THAT different! The tube in the center of the wheel seems to be wrong. Not sure how that can be since it is the one I took out. Something is clearly not right though. I think that if the races were not all the way in the hub, the pipe in the center wouldn't seem to be too long. This is a wright buggers muddle and I'm the air head here!

You're right. The new bearing can't be that different. Plus, you're working with the original spacer and the original wedding band. So, for the new bearing fit to be so far off, a basic premise or assumption is wrong. Can you give us an estimate of how far away the inner race is from seating into the outer race? I get the impression from your posts that there is a lot of space between the two, at least 10 thousandths of an inch (0.010"). Does that sound right, or is it significantly more or less than that?

The bearings you took out have 30203 written on the outer races, right? And the bearings you put in also have 30203 written on the outer race, right? And to the best of your belief the spacer and wedding band were operating as designed, right?

As an aside, you know you don't have to buy those bearings from BMW. Your local bearing shop will likely have them in stock at about 1/2 the price. If the bearings from the bearing house are a name brand, I would not be concerned about the quality. It will be equal to the "correct" bearings specified by BMW. I would suggest that you go to a bearing house and buy a couple 30203 bearings. I keep those bearings in my personal stock against the day when I will need one. If you have the bearing house bearings in hand you can then compare them with the BMW supplied bearings that you are trying to make work. And if you go ahead and remove the outer races of the BMW supplied bearings from the wheel then you can make some direct comparisons.

By the way, do you still have the old original bearings that you took out for comparison?

With those various bearings in hand you will be able to get to the solution of this mystery--if the bearings are at fault! And then, if it isn't the bearings, well, we have narrowed the search to other things such as the wheel or some other problem.

By the way, are you convinced that the old bearings you took out of the wheel were preloaded correctly? Sometimes previous owners do some strange things. An '81 R100RT that I bought had major problems with the rear wheel. Cutting to the chase, when I finally got things apart the wedding band was missing entirely. And somehow the bearing, which might have been massively preloaded, managed to spin on the axle, which by virtue of that spinning, became the de facto bearing on the wheel. I can only imagine that the previous owner found the wedding band after the put the rear wheel back on the bike, and not having a clue what it was for, then threw it away. From his perspective the motorcycle continued to work just fine, thank you.

Ken