I don't know the diameter of the wheel. I got the pic off of e-bay.
The steering wheel is on a nice short box truck.
Here is the link.
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=2403418967
LMC has the wheels at $100 plus $20 for the installation kit.
Grant must make them but I have not looked it up yet.
Jim