Has anyone made an adaptor to change wider than 10" wide wheels for a Coats 10-10?  I have several old modified  14" to 18" wide wheels and need a way to bust them down. Another problem I have is the5/8"  valve stem on some Weld wheels falling into the tire. Perhaps some brand of high pressure valves??? I guess I'll need to machine up a slug and weld it in, lotta work for a simple problem.

Gene, make one.  Triangle steel plate.  Weld three 5/8 studs or bolts to it.  You just need the extension for the dismount bar.  Not necessary but need it so the dismount bar does not jump off and hit you in the face. I will pst a picture tomorro. 

And flame cut a hole in the middle for the hold down

I made a plate for the wide 5 pattern. But with the wheel offset, the plate is higher than the center post, no way to anchor the wheel to the machine.  I could use a manual bar and peel those tires off, but that is not why ya have a machine. what would be nice if someone had a threaded post to fit over the OEM post. Maybe I could get a stock tapper nut and machine it down and slide it into a 3" piece of schedue 80.

They used to sell the extender. I looked/googled, but could not find. Possibly get a stock one and weld/extend it.

As far as the 5/8 valve stems I would start at your Local NAPA store. That is a truck and tractor size and they should have brass on that clamp in . Or try a truck or farm implament repair shop. 

Truck, trailers and early VW use 5/8" stems