Trouble with pneumatic tank drive

[GeeTwo]

Originally Posted by TimTheGreat

So we're using the nano tube transmissions from andymark, as well as the 8" pneumatic wheels from andymark. I don't have an exact number for the PSI, but we pumped them up until they were basically rock hard.

That's what we have for our air cannon, with the long (31"?) tubes. The drop center is not enough to turn well at low speed. You may find that you can turn better if you're accelerating or braking, as one pair of wheels comes up a bit. If we were using this chassis base for competition, I would definitely increase the center drop. If you want good travel over the obstacles, you may want to decrease the tire inflation, which would require even more center drop. Fortunately, the center is not one of the directly powered axles (unless you've got the one with gears all down the length). If you're driving that with chain, you might do well to go dead non-rotating axle and put bearings in the wheels rather than a hub, which will allow you to add a plate over the stock bearing hole and use a smaller (e.g. 3/8") hole for a bolt.