[FTC]: Can I add non-slip material to 4" Tetrix Wheels?

[aklego]

The 4" limit only applies to purchased non-Tetrix/Matrix/Lego wheels. Teams can modify or build wheels to be > 4" as desired, subject to the allowed materials, field damage, and 18" size constraints. There are several official forum post dealing with this issue and it might be a good idea to have printouts handy as the above posts make it sound like some teams have been wrongly failed at their tech inspection.

All that said, if you have a quick way to make your robot 4 wheel drive (chains or gears?) you will likely get HUGE improvements in traction and drivability.