[Veselin Kolev]

Okay, prob with all these friction coefficients and stuff is that its all on carpet. You gotta be good on that wire mesh stuff too, and on the HDPE. We'll see what next years game is really soon.. but I can tell you about my team's wheel problems. Over the last few years my team has used the cross hatch "wedge top" stuff from McMaster. It has really good traction on carpet and fairly good durability on carpet. Its ok on the HDPE, but the wire mesh really kills it. If you try to push your way up onto the ramp with that stuff, all you do is burn out your wheels and cut them to shreds on the wire mesh. In fact, me and rest of the drive crew commonly refered to it as the "cheese grater" Yea... in half a day, our wheels would be slicks. Trash. So.. after seeing this at the Sacremento Regional, we invested some research into special wheels designed just for certain materials. For example, we had wheels with notches on them every one inch, giving amazing traction on the wire mesh. We only had 2 of our wheels like this, and the other 2 were I believe polyethelene... I can't remember, but they were really sticky rubber with crazy traction on the HDPE. Both of these tracks are on McMaster, and are usable just like the cross hatch tred. Of course, we didn't have as good traction on the carpet anymore, but our strategy didn't really call for that. We gave our robot traction where it needed it most. You can't have good traction on all 3 materials, its just too hard.
In the end, I feel that the cross-hatch tred is the best to start with, and it has good traction, but its durability might be a good reason to later change to another set of wheels. As JVN said, be prepared to have a few (actually a lot) of spare wheels.

Now for the fun part... I think that the best drive system (traction-wise) would be tank treds with a fully independant suspension on every support roller!! Just like modern day tanks. Hug the terrain. Man... what I would give to see ANY robot with a suspension on its wheels. So far, I've only seen one team that had 6 wheels use a suspension on the middle wheels.

Here's a question, how do teams that use treds like the cross hatch stuff attach them to wheels? My team uses the 8 inch skyways with sprocket hubs and we epoxy the tred on and use screws to keep the ends from tearing off. Anyone do it differently?