Several inquiries regarding the adapters. here's what I think I know.
The tool comes with a 20 mm rod (which will fit for example, a DRZ with a 20 mm axle).
There is also a 25 mm sleeve to shim it for a larger axle.
An optional 15 and a 17 mm adapter are available for smaller axles, I'm thinking 200-250 cc dual sports / dirt bikes, or even a KLR. There is also an optional "pusher rod" that is shorter than the one in the kit, I'm thinking mini-bike or scooter??? Are did build 1 special adapter for croc, and it was only like a couple more bucks than the standard optional adapters.
You just need to verify the axle sizes for the wheels you would be working on. It seems to me, after playing around with my tool (that's "tire tool") that you could make a simple sleeve if you needed something between 20 and 25, or bigger than 25. And I'm not sure it would hurt if there was a little play, say you were using a 25mm adapter but your axle was 28mm. YMMV.
Has anyone used this on a 21 front? Is it long enough? That's the other question I've had, but I haven't tried a front yet. I'm building a 19 to replace my 21, but it looks like it will work on a 19, if I ever get to that part.