[EricH]

Reduce traction for one set of wheels. Now that I've given the solution, here are some possible ways to implement it:

--Add a middle wheel to each side, dropped slightly from the rest.
--Swap 2 of the 4 wheels for omni wheels (not easy if you don't have said omnis, but that's something to think about for later seasons)
--Swap one end's wheels for lower-traction wheels (or possibly higher-traction wheels... but that's not something I'd try)
--Grab a roll of duct tape and wrap it around the tread on one end of the robot. Replace every couple matches or so.
--Grab a couple containers of zip ties and put zip ties around the treads.

And, at the end of the event, grab a roll of field carpet if you can (talk to the FTA and arrange a transport vehicle); this will allow you to test your drivetrain under competition field conditions in future years.