B50 rear hub

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B44Claus
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B50 rear hub

Post by B44Claus » Thu Oct 15, 2020 6:45 pm

Evening Gents,

I just put new bearings in the B50 rear hub I recently acquired. After assembly the brake plate is not locating properly on the hub:
Hub1.JPG
The brake plate should be closer by about 5 mm.
What's going on? I have carefully seated the bearing on the brake side:
Hub3.JPG
Hub4.JPG
Or should the bearing sit deeper in the hub?
Anything wrong with the brake plate:
Hub2.JPG
The right side bearing sits 10.5 mm down in the hub:
Hub5.JPG
Any obvious mistakes observed before I remove the bearings again?

Brgds,
Claus
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Re: B50 rear hub

Post by SteveS » Thu Oct 15, 2020 7:04 pm

Hi Claus

It doesn't look right does it? However it is correct, the brake plate sits clear by about 4mm
Steve Sewell

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Re: B50 rear hub

Post by beesa71 » Thu Oct 15, 2020 10:02 pm

I agree with Steve, all looks correct.

Only comment I’d offer is that don’t forget that the speedo drive side bearing is not locked in by the screwed in speedo drive ‘ring’.

Paul.

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Re: B50 rear hub

Post by B44Claus » Fri Oct 16, 2020 12:13 pm

Thanks for the feed back guys,

Although encouraging that it's supposed to be like this it still looks silly. Is it the same on all OIF's with conical hubs?
On previous models the brake plate was a close fit on the brake drum/hub to keep dirt and chain lube out.
Not so on the B50 which has an air gap:
Gap1.JPG
Was the MX edition of the B50 any different in this respect?

Regarding the speedo drive ring; I was not intending to fit any as the bearing is held in place by the distance piece:
Spacer1.JPG
Spacer2.JPG
Brgds,
Claus
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Re: B50 rear hub

Post by SteveS » Fri Oct 16, 2020 12:39 pm

Hi Claus

No, all the oif models were the same. I've never experienced a problem with the rear brake getting contaminated. Other more serious MX'ers may be able to better advise
Steve Sewell

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Re: B50 rear hub

Post by koncretekid » Fri Oct 16, 2020 1:05 pm

If the internal spacer is not original, it could have been made incorrectly. From memory, it looks like the reliefs on the ends aren't machined as deep as the bearings, which would prevent the offside one (which doesn't bear against anything) from seating deep enough. I don't have the exact size, but somebody who has one apart may be able to supply the correct dimensions.
Tom
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Re: B50 rear hub

Post by beesa71 » Fri Oct 16, 2020 1:26 pm

I disagree; ‘from here’ the bearing spacer and it’s ends look fine and as mine do.

Paul.

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Re: B50 rear hub

Post by Momus » Sat Oct 17, 2020 7:00 pm

beesa71 wrote:
Fri Oct 16, 2020 1:26 pm
I disagree; ‘from here’ the bearing spacer and it’s ends look fine and as mine do.

Paul.
Koncrete is talking about the bearing spacer in the hub, not the wheel spacer.
If you love it, lube it.

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Re: B50 rear hub

Post by beesa71 » Sat Oct 17, 2020 7:29 pm

That’s what I said. The bearing spacer ‘in the hub’ not the MX (only) spacer that sits between the bearing and the swinging arm.

Regards to all OIF’ers.

Paul.

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Re: B50 rear hub

Post by SteveS » Sun Oct 18, 2020 9:16 am

.
A while back I took some measurements of the bearing spacer 37-3753.
.
Steel tube made from 1" material with a clearance hole for the 5/8" rear wheel spindle and stepped at each end to take the 20mm diameter wheel bearings (Hoffman 120, Size: 20x47x14mm)
.
37-3753 dims.jpg
Bearing spacer 37-3753
.
As I said it was some time ago and looking at the measurements they don't quite stack up correctly, so beware.
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Re: B50 rear hub

Post by beesa71 » Sun Oct 18, 2020 11:31 am

And here’s one I’ve just measured. Other dim’s concur with Steve.

Paul.
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FACA2AD0-887C-4773-9AFC-2CE3EFEB457A.jpeg
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Re: B50 rear hub

Post by B44Claus » Sun Oct 25, 2020 11:56 am

Thanks guys,

Measuring the bearing spacer with calipers works out at the same dimensions you get. I can't do it very accurately as it's installed in the hub with bearings on but close enough to conclude the spacer is OEM.
Still puzzled why the brake plate is not closer to the hub but I'm satisfied that it's supposed to look like that.

Brgds,
Claus
B44Claus

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