Urethane Drive Wheel Questions

[mrnoble]

We are interested trying some new wheel options out for fun (and maybe style) in the off season. Though we are going to have a new facility with machine shop by January (fingers crossed!), right now we need to do it with off-the-shelf.

I found these, and they look promising. http://www.sunray-inc.com/online-store/drive-wheels/

We would be getting the aluminum hub, 4" x 1.25" models. Though expensive at $30 each, it's not a huge investment and may be an upgrade. We would broach the hub ourselves for 1/2" hex/thunderhex shaft. My questions:

• Has anyone tried using urethane tread on FRC carpet?
• What were your results, in terms of CoF relative to other popular choices, like Colsons and wedgetop blue Nitrile?
• What did you find in terms of durability?
• What durometer rating(s) did you try?

Also,

• What size bore would you recommend for finishing with the 1/2" broach?

Thanks, I look forward to your responses.