Rear wheel bearings

chasbmw · Jan 21, 2014

I'm in the process of changing the rear wheel bearings on my new to me 71 750.

According to the parts book the bearings consist of a pair of single row bearings, they each have the same part no.

However the drive side of the rear hub is machined to a depth that would take a double row bearing and the center spacer has one end longer than the other and also looks as if it would take a double row.

Can anyone shed some light on this

Thanks

Al-otment · Jan 21, 2014

If a double row will fit in there then go for it. Can't see it doing any harm. You'll have to modify the spacer tube though.

L.A.B. · Jan 21, 2014

Is the rear wheel assembly the (post '71) "cush" type , or the pre-'71 "bolt-up" (brake drum bolts to hub) type?

If in doubt, see manual, Section H.
http://www.classicbike.biz/Norton/Repai ... mmando.pdf

If cush type, the double row bearing goes in the drum/sprocket.

Hobot · Jan 21, 2014

If cush type, the double row bearing goes in the drum/sprocket.

The sealed double row supplied by Old Brits is a bit wider than the drum bore is deep so drum will need a bit of milling deeper to seat in enough the circlip engages. Can send in drum for them to do it or bargain with machinist to do the simple but tricky job. Loose lips sink ship and loose bearing breaks axles.

L.A.B. · Jan 21, 2014

hobot said:
The sealed double row supplied by Old Brits is a bit wider than the drum bore is deep so drum will need a bit of milling deeper to seat in enough the circlip engages.

However, the correct (16mm) width double-row sealed bearings are available from various Norton parts suppliers.

chasbmw · Jan 21, 2014

This is what confuses me.....I have a later Cush drive hub, which is supposed to be fitted with 2 single row bearings.

The hub is machined on the drive side, deep enough to take a double sided bearing and the central bearing locating tube is also fitted with a long and a short end, which according to the manual is a feature of the pre 71 bikes.

The bike was fitted with 2 single row bearings and most of the build on this bike seems to be OK, I'm recommissioning a bike that has been in a collection with very little use since 1999.

L.A.B. · Jan 21, 2014

chasbmw said:
The hub is machined on the drive side, deep enough to take a double sided bearing

If I remember correctly, many British bike wheels usually have only one positively located bearing, that's the bearing on the lock ring side (timing side, Commando rear, '71-'74), the other bearing basically finds its own position so doesn't locate against a shoulder in the hub, only the spacer tube.

Hobot · Jan 21, 2014

Code:

However, the correct (16mm) width double-row sealed bearings are available from various Norton parts suppliers.

Yep I think I got those prorper correct version from Baxter's Cycle for early '72 Peel in ''01 but was on shopping spree with Old Brits on late '72 Trixie in '09 so got the wider version a local shop did bore, with comment it stressed them d/t the tool bits they had to do the bore. It'd been so long after Peel I'd forgotten the specifics so figured Old Brits with their constant world wide supply and feed back had the good stuff so a no brainer for me, though was told about the bore issue and options when I ordered.

Al-otment · Jan 21, 2014

L.A.B. said:
chasbmw said:

The hub is machined on the drive side, deep enough to take a double sided bearing

Click to expand...

If I remember correctly, many British bike wheels usually have only one positively located bearing, that's the bearing on the lock ring side (timing side, Commando rear, '71-'74), the other bearing basically finds its own position so doesn't locate against a shoulder in the hub, only the spacer tube.

This makes sense.

chasbmw · Jan 21, 2014

L.A.B. said:
chasbmw said:

The hub is machined on the drive side, deep enough to take a double sided bearing

Click to expand...

If I remember correctly, many British bike wheels usually have only one positively located bearing, that's the bearing on the lock ring side (timing side, Commando rear, '71-'74), the other bearing basically finds its own position so doesn't locate against a shoulder in the hub, only the spacer tube.

Thanks LAB, I'll fitted both single row bearings and forget about it.

Thanks everyone for their help

ashman · Jan 21, 2014

Its important you do your rear sprocket as well (dunny sharf)

ILLF8ED · Jan 21, 2014

Just measured the depth of the bearing "hole" on the sprocket side of a bare crush drive hub in the garage... .612". The 6203 wheel bearing that came out is .475" wide.

Rear wheel bearings

chasbmw

Al-otment

L.A.B.

Moderator

Hobot

L.A.B.

Moderator

chasbmw

L.A.B.

Moderator

Hobot

Al-otment

chasbmw

ashman

ILLF8ED

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