[SJaladi]

While I've never actually driven a T-Shirt Cannon robot on a Football field, my past experience with pneumatic wheels vs. other common FRC wheels tells me that pneumatic wheels are probably the way to go for driving on turf/grass. The one thing you will want to watch out for though is that if your center drop (I'm assuming you're running at least 6 wheels, in the standard tank configuration) is too small then the deformation of the pneumatic wheels under the weight of the robot will cause all the wheels to touch the ground and cause increased turning scrub. Therefore you may have to play around with finding the right pressure to inflate the wheels to and the right amount of center drop.