OK so I didn't take enough photos....

[peteremc]

I know I didn't take enough photos but I also certainly didn't think I would need them for anything as simple as installing the rear wheel!

Long story short: After being apart for about 12 months I went to fit the rear wheel. Positioned the wheel, picked up the axle and there it was, the way it came apart, apparently, with large nut & washer on one end and spacer up the other end. When it came time to fit the wheel there was no room for the spacer.

I measured from the lip down the left hand end of the axle to the other end where the nut/washer are and compared it with the distance through the centre of the wheel/final drive. Both the same, so no room for the spacer.

Wheel looks and spins fine. Axle sits fine in the swing arm where the pinch bolt is. There is just enough thread out the right hand end for the nut/washer.

Do I now have different bearings/seals fitted that do not require this spacer? I see some diagrams show a thrust sleeve on the left end of the axle and wondering if this is it? Photos of each side of the axle and the (now redundant) spacer/sleeve attached. Any ideas?

[Tony Smith]

The "top hat" spacer you have left over is needed (assuming you used the same TYPE of bearings when you put the wheel back together).

I'll vet you money that if you take the wheel off again and gently remove the RHS grease seal, slip it over the top hat and reinstall, not only will your wheel still fit, but this time you will be able to actually tension the bearings more or less correctly :-)

[peteremc]

Had the wheel off and that grease seal is not going over that spacer. It is the same inside and outside diameter as the seal (17mm/22mm) - and that is not the top hat end. Which makes this more intriguing. I had a professional fit the bearings so will have to check back with them.

Thanks anyway

[montmil]

Top Hat belongs...

[Barry]

Had the wheel off and that grease seal is not going over that spacer. It is the same inside and outside diameter as the seal (17mm/22mm) - and that is not the top hat end. Which makes this more intriguing. I had a professional fit the bearings so will have to check back with them.

Thanks anyway

I measure my top hat as 22mm OD.  Normal assembly is to install the seal over the top hat with the brim inside the seal although functionally it doesn't actually matter which way around the top is. It's just a spacer that butts up to the inner race on one side and the shoulder of the axle on the other side. A spacer without the brim would work just fine. The seal should be sized for the spacer OD as it's the surface of the spacer that the seal runs on not the axle.

Seal size is 22x40.

[nhmaf]

Many here do install the tophats with the brim on the outside, so one can check and even work in a bit of grease on the bearings without having to rip and replace the seal with the brim on the inside.   You definitely do need them.

How much space is between the edge of the wheel hub and the edge of the cardan drive housing? - it is hard to tell with the black paint, but it seems like the wheel  hub edge might even be contacting the cardan cover - usually there are a a few millimeters of space?

Also, that "mushroom cap" top vent plug is what your final drive uses to breathe - necessary when the oil in it heats up while riding.  If it is shoved all the way down as it appears to be it can prevent theventing from inside to outside.   There are a couple small punched notches up inside the "cap" that slides in the other threaded part - unscrew the whole thing from your final drive, put the hexagonal part in a vise and gently tap the "cap" upward so you have a couple millimeters between the bottom of the cap and the hex "nut" surface - now air can easily get in & out.     Then, reinstall into the cardan cover - do not overtighten!

[mrclubike]

How wide is it
Sure looks like a top hat spacer
the front wheel has one and the rear has 2

[montmil]

Wondering if the bearing installer guy actually got the outer race fully seated. He would not be the first. They would possibly explain the top hat issue.

[peteremc]

OK, solved the mystery. The left-hand top-hat spacer came out when I removed the axle originally. so I left it on the axle. New bearings were not inserted in the rear wheel as they were replaced (by the same workshop) not long before the bike was was taken off the road. But while they had the wheels it was noticed that one spacer was missing and was replaced. So, all good and I have a spare spacer in the "bits left over" bin when I'm finished this project.