[IKE]

Please elaborate on "smoother" surface.

Last year we found that there was a dramatic difference on the polycarbonate between the various wheel types. The Hi-Grip, when clean had a lot of traction where-as wedge top (usually a pretty good choisce for carpet) was quite poor.

Colsons were nice in that they had the least change (for us) surface to surface. If you are not worried about durability, in general the softer the durometer, the grippier the wheel.

There are also some really neat compounds out there that have exceptionally good grip.