[Jon Stratis]

The biggest difference is with tipability (if i may create a new word). Basically, most long robots are difficult to tip over, while many wide robots are easier to tip over. You can go to extremes, of course - a very long and narrow robot might be easy to tip over sideways, for example... but usually that's not something people worry about much.

Tipping, or popping wheelies, is all about center of gravity. If your center of gravity is too high, then any robot can tip over easily. On the other hand, if you can design your robot so half the weight is within the bumper zone, it's going to be hard to tip over no matter what you do.

Thinking back to Rebound Rumble, I can't even count the number of teams I saw tip over from the bridge - a lot of tall, boxy robots with their center of gravity too high. They would get half on the bridge, their alliance member would back up tipping the bridge, and they would fall right over. Robots with a proper center of balance didn't have that issue - with our robot, if the alliance member tipped the bridge too early we would lean back and everyone would gasp, but then the alliance member just tipped the bridge back, we landed on our wheels, and completed the balance. With that robot, we had 60+ lbs within the bumper zone, and had to be tipped greater than 85 degrees before we would fall onto our back.

With wide robots, you might be able to get away with 2 wheels, while long robots need at least a third drop center if you want to be able to turn.