different rear /5 wheel hubs. is something missing?

[Deleted User 62]

EDIT: I see now that as Timo pointed out, the diagram is somewhat deceiving in that the "small top hat spacer" and other spline-side parts are drawn/shown on the wrong side of the hub.

Actually, the fiche pictures generally show the order of assembly by number, but this one is confusing because while it shows the rear wheel splines on the left, it also shows the reduction tube for the front axle on the right. It's possible the small top hat is shown where it is because it is inserted at the same time as the bearing stack, eliminating the need for a new seal on the inboard side. The proof would be if it can't be installed from the spline side.

[jjwithers]

I got the felt and the cover for the hub. It seems that the felt fits perfectly into the cover... and the cover will fit into the cast of the hub with some tapping of a hammer.

Here is my issue regarding that Top Hat on the spline side...

On the /6 wheels and later, the top hat can get inserted into the rubber dust seal on the spline side of the hub.
So you can install or remove the top hat spacer anytime you want (as long as the wheel is off the bike).

On my /5 wheel, the top hat spacer fits nicely in the hole of the felt and felt cover, but the lip of the top hat sits on the cast of the metal. I feel this is incorrect and it should make contact with the bearing (through the casting of the hub) and not sit on the casting of the hub.
Now i see why the design was improved a few years later.

If the top hat should indeed make contact with the bearings, at this point, i guess the bearings have to get pulled and the top hat needs to get installed FIRST into the hub.
OR
the top hat gets shaved down a wee bit to fit through the hub hole. (not correct but maybe worth a try).

Can somebody confirm if the spacer should touch the bearing or not?

[Deleted User 62]

Yep, spacer should touch the bearing to preload it. If I'm not mistaken, the edge of the bearings center hole has a bit of curve, so cutting down the top hat is probably not the way to go.

[jjwithers]

It's late and perhaps my brain is fried. i just took another look at it and the top hat does indeed make contact with the bearing... so it looks like i don't need to worry about removing the bearings.
phew.
And, For what it is worth... the felt and the cover hold that top hat in place when you mount the axle through the wheel.
Hopefully this case is closed. Mystery solved. And somebody else trying to analyze a /5 wheel can benefit from my photos and follies.

[Duane Ausherman]

The top hats only purpose is to carry the pressure against the bearings for the preload. It is needed as the place where the pressure part goes through the seal. It doesn't matter which way the top hat goes. BMW changed it on the /6 so it wasn't as likely to fall out as it did on the /5.

I know that this is hard to describe and maybe harder to understand. If we were together in the shop, I am confident that I could explain and show it in a way that would make sense. Once understood, it is a really simple and reliable system.

The felt is on the inside because it is mostly clean in there and felt is not very good as a seal, but it is cheap.

[KauaiSlash5]

I got the felt and the cover for the hub. It seems that the felt fits perfectly into the cover... and the cover will fit into the cast of the hub with some tapping of a hammer.

Here is my issue regarding that Top Hat on the spline side...

On the /6 wheels and later, the top hat can get inserted into the rubber dust seal on the spline side of the hub.
So you can install or remove the top hat spacer anytime you want (as long as the wheel is off the bike).

On my /5 wheel, the top hat spacer fits nicely in the hole of the felt and felt cover, but the lip of the top hat sits on the cast of the metal. I feel this is incorrect and it should make contact with the bearing (through the casting of the hub) and not sit on the casting of the hub.
Now i see why the design was improved a few years later.

If the top hat should indeed make contact with the bearings, at this point, i guess the bearings have to get pulled and the top hat needs to get installed FIRST into the hub.
OR
the top hat gets shaved down a wee bit to fit through the hub hole. (not correct but maybe worth a try).

Can somebody confirm if the spacer should touch the bearing or not?

Sounds like you got it figured out on the spline side, but looking at your picture I notice you forgot to install the "wedding band". It's still on your finger

[jjwithers]

Sounds like you got it figured out on the spline side, but looking at your picture I notice you forgot to install the "wedding band". It's still on your finger

LOL! That wedding band seems to slow down my motorcycle build progress all the time...

[Duane Ausherman]

The part on his middle finger isn't the wedding band, it is the top hat. The felt and retainer go in and stay in place. The top hat can be installed with the stack. It is very important to install the stack as a whole and not in pieces. Or, the top hat can be insalled by itself first. It really matters little.

I like to modify the inner spacer (the part that the wedding band nests in) so that it will be through the outer race. That way you have more flexibility in service and cleaning without removing the stack. One really doesn't want to remove the stack any more often than absolutely necessary. Each time one runs a small risk of taking a small amount of metal out of the hub. That will hasten it in spinning.

Am I making any sense in this? I have edited my page on wheel bearings at least 50 times and it should be self explanatory by now.

[jjwithers]

Duane... the part about the wedding band was a joke...

[Major Softie]

Duane, if you will look further down the ring finger in the photo, you will see an actual wedding band.