Ah, good to know. At the Championship, we were trying to come up with a quick fix for an encoder disk (previous wheel had a piece of retro reflective tape on the hub) and discovered that the wheels are really tough to work with.
Having made hubs for both Colsons and these Urethane Wheels, I can say that the hubs are similar, but a hub made for a colson would be too small for the urethane wheel. If you really wanted to, you could sleeve the urethane wheel with a piece of 1.25" (nominal) tubing that’s somewhere around 1/32" wall and probably make something work, but at that point, it might be more prudent to just make hubs that are the correct OD.
I have a drawing somewhere of the hubs that we’re running in our urethane wheels, if you need it/it’ll help expedite getting them made in time for IRI, shoot me a PM.