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bearing location in rear wheel

6K views 10 replies 4 participants last post by  DeltaPapa 
#1 ·
hi, rebuilding my rear wheel (1969 T100C) after powder coating hub...

I started from the right, drove in grease retainer,then a new bearing. I drove the bearing down until it contacted the retainer, then placed the thin grease retainer, then screwed in speedometer adaptor.

There is about a 3/16" gap between the retainer and the bottom of speedometer adapter (see pic). Is this correct or should the speedometer adapter tighten up against the retainer to hold the bearing in?

I am pretty sure that I have all the correct parts. Unfortunately my before pictures dont show this clearly.

thanks, trey
 

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#2 · (Edited)
Hub and speedo adapter are the same part numbers for a 1970 650 and a 1971 500. If this is consistent with your 69 (I don't have a 69 parts book) then I believe the speedo adapter should butt up flush against the grease retainer, shown in your photo, without any gap. The bearing should sit about .25" below the rim of the hub. Bearing is .549" thick. Hopefully someone with your specific model can confirm.
 
#3 ·
here is the before pic. I did not zoom in on the bearing so I cant tell the exact distance. I dont think the bearing can be 0.25" from end as it would then still be sitting on threads. What i dont get is if the adapter is supposed to be abutting the retainer, then how did i mange to drive it too far as I am quite sure there was an inner flange that the inner retainer sat up against.
 

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#4 ·
I believe the drive side bearing butts up against the spacer, grease shield and shoulder in the hub. The distance piece will dictate how far to drive in the timing side wheel bearing. The bearing is not driven against the grease shield on the timing side and may extend into the threads a bit. This is the condition I found in my wheel. Hopefully one of the esteemed experts will drop by to confirm or correct. I will dig through some references and photos and post if anything meaningful can be found.
 
#5 · (Edited)
These pictures were taken when I changed the bearings. The old bearings seemed to be in good shape but, what the heck, bearings are cheap and I need to have fun. I'll save the old ones just in case the new ones die early.

These bearings were, I believe OEM and had never been changed. The drive side had "Hoffman" stamped into the edge and the timing side had "Fafnir made in the United Kingdom C4" etched into the bearing surface.

The first image shows the timing side with the speedo adapter snugged up against the grease shield.




This image shows the timing side with the speedo adaptor removed and shows a bit into where the spindle goes and shows that the bearing is flush with the distance piece. Note the highlight just to the right of the shadow in the hole. That is where the distance piece meets the bearing. This bearing extended a bit into the threaded part of the hub.

 
#6 ·
thanks for the insight! So here are my new positions for the drive (left) and timing (right) side bearing and retainers.

I drove the timing side bearing back out until it was flush with the bottom of speedometer adapter (see pic). So it looks like henryanthony's pic above

I then placed the distance piece and the retainers on the drive side, but havent pushed in the drive side bearing in because I am still a bit unsure.

It seems that with the distance piece in there ,the position of the bearings within the hub is not locked in, that I can shift them to either side by about 1/8". Whats strange to me is that on the timing side, there is a flange in the hub. I thought that this flange was the stop for the grease retainer, but if I drive the grease retainer up to it, then there is that gab under the speedometer adaptor.

On the drive side in the photo it also seems that the distance piece can be higher or lower relative to the retaining ring, depending upon how far you set the timing bearing in. So I am not sure if the distance piece or the retaining rings or both should be flush with the drive side bearing.
 

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#7 ·
I found these notes about the Drive Side of my hub (remember, this is for a 1970 T120R):

These dimensions are nominal as measured unscientifically by hand with a digital caliper but should be close enough to demonstrate my point.

.935" - Depth from hub rim to shoulder

.016" - Grease Retainer
.063" - Backing Ring
.550" - Wheel Bearing
.279" - Retaining Ring with locking screw
.908" - Total

From depth of .935"
Subtract Total of .908"
Equals .027"

Prior to disassembling, I measured the depth of the hub rim to the retaining ring and noted .029" - which is close enough to .027". This tells me that the Drive Side bearing and assorted rings are driven against the shoulder and locked in by the Retaining Ring. Add the distance piece and drive the Timing Side bearing against it and lock it in place with the Speedo Adapter. I don't see any other way to assemble this (doesn't mean my method is correct though).

In my parts manual and workshop manual, if you look closely, the exploded illustration of the rear wheel shows cupped grease retainers on both sides of the Timing side bearing. I only have a cupped retainer on the inner side of the bearing and a thin, flat one on the outer side. The inner side is 3/16" thick. Perhaps the outer retainer was changed to the flat one which resulted in the gap you see.

If using sealed bearings, I don't see the need for the Timing Side inner grease retainer other than as a support for the distance piece during assembly.
 
#8 ·
Well, after discussion with my local shop, who works with an old-time triumph expert, this is where I ended up:

While the right grease and bearing get inserted first, their final position is dictated by the left side! The critical dimension deals with the the inner portion of the bearings. The distance piece, when set on the right bearing, must extend beyond the left backing ring (WI 022) so that the all inner portions carry the compressive loads when the inner shaft nuts are tightened.
 
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