Cush Drive Rear Hub Alternatives

I'm in the process of getting a 1970 XS1 back on the road, and I'm considering swapping in a cush-drive rear hub. I've read some posts here about cush-drive rear hub alternatives (e.g., TX500, TX750), but it's not clear as to which is the most plug-and-play alternative?

Interested and watching.

patentgeek said:

I'm in the process of getting a 1970 XS1 back on the road, and I'm considering swapping in a cush-drive rear hub. I've read some posts here about cush-drive rear hub alternatives (e.g., TX500, TX750), but it's not clear as to which is the most plug-and-play alternative?

Click to expand...

Hi patentgeek and welcome,
love the Wallace & Gromit avatar!
Never done a cush-drive rear wheel swap but amongst the other parameters there's two things I'd suggest to watch for.
Will the new cush rear be a near-enough lookalike to the existing front wheel or should you budget for a matching front as well?
Will the new cush rear hub have a small enough bolt circle to fit a 32T rear sprocket?

The TX750 wheel is "plug and play" but it's not a cush drive. It uses the same solid sprocket mount as a 650 wheel. The 500 wheel is nearly "plug and play". It uses the same axle size and sprocket mount as the 650 so just some re-spacing is required. As luck would have it, the spacer thicknesses required correspond to the sprocket thickness so it can be used to make them. This means no expensive trips to the machinist for custom made spacers. The backyard mechanic armed with an angle grinder and some cut-off wheels can literally make them in his backyard.

I'm not aware of any other rear wheels that readily swap in, but that doesn't mean there aren't any out there. There could very well be another wheel from some other bike brand (Honda, Suzuki, etc.) that could be easily adapted. I kind of accidentally stumbled upon the 750 and 500 wheels. A buddy was moving out of state and gave me the 750 wheel so he didn't have to haul it with him. I knew the 500 wheel was sitting in my dealer's bone yard because I put it there years earlier. I reclaimed it originally because I discovered it used that same funky top hat spacer in the left wheel bearing as the 650. When I discovered it had a cush drive and took the same sprocket, I figured it would be worthwhile to try and adapt it for 650 use.

Thanks! Super helpful information.

I'm not concerned about front/rear wheel mismatch as I'll probably be using a 4LS Water Buffalo front hub I have lying around.

Great to hear that the TX500 hub has the same axle diameter and sprocket bolt circle diameter. I have a full size lathe and mill, so trimming down a sprocket to make a spacer isn't a big deal.

5twins, what's up with your rubber cush drive cut into sections?

If you have the lathe and mill then the XS650 rear hub can be converted to a cush drive hub.
http://www.xs650.org.au/Technical Info/hub conversion.htm

If you want to go disk rear a couple years of the GS750 GS1000 are an "easy" conversion. 530 conversion sprockets are available the zookies ran 630 chain.
i have one laced to a wider 18" rim now using mikes SS spokes but not mounted. Think I need to skim a bit off the sprocket flange on the cush drive for sprocket alignment. Axles are same diameter which saves a lot of hassle.
this thread maybe of interest. http://www.xs650.com/threads/disc-conversion.32475/#post-329173http://www.xs650.com/threads/disc-conversion.32475/#post-329173

The cush drive in my pic is original and stock. It consists of 6 slotted rubber "pucks" that fit into compartments in the hub. The sprocket carrier has 6 big tabs on the back that fit into the slots .....



My wheel was in pretty rough shape because it sat outside for many years. The cush drive was froze up. The sprocket carrier has a steel insert that rotates on a steel sleeve on the hub. They must be kept lubed or they can rust together. As you can see above and below, mine got pretty rusty .....



After I cleaned them up, I gave the mating surfaces a thorough coating of anti-seize .....



There's an album on my media page here on the site with lots more pics documenting the process. Have a look if you like. So far, I think this is about one of the easiest wheel swaps to come along. No hub machining is required, just a few spacers need to be made up. Since you have a lathe, you could make some fancy ones, but all that you need is already there "in" the rear sprocket. You just need to cut them out. Only 2 ring spacers are needed for the axle, one on each side of the hub, I just cut out a few extras .....

Thanks for the additional info 5Twins. The TX500 wheel conversion definitely seems like the easiest way to go. Your cush drive pucks looked kind of odd to me because they are asymetrical, but that actually makes sense from a design perspective. I see a pic of a BMW /5 front end on your media page. I have a '70 R75/5 myself.

Might be worth noting that dampening is built into the driven gear attached to the clutch basket. Some people swap springs there and leave some out or replace some with rubber.

I've thought about swapping in a later clutch basket that has an improved cush drive. However, I'm rebuilding the wheels anyway, and I like the simplicity and robustness of a hub-type cush drive system. The Clutch Mod tech doc on the Australia site indicates broken clutch basket cush drive springs are not unusual.

http://www.xs650.org.au/Technical Info/clutch.htm

Yes, broken springs on the back of the clutch hub are not unusual. That's why I think anything you can do to ease the strain on them is a good thing. A cush mount for the rear sprocket is one thing you can do. Another is to use the '80 and later inner basket with the dampened bottom plate. It engages more smoothly.