pic: ABS-122, shifter-in-tube chassis

[Cothron Theiss]

Originally Posted by GeeTwo

I know it sounds strange, but if this is the case, I would seriously consider not driving the back wheels at all -- save the chain and sprockets and heartache. I might even consider skipping the back wheels and putting some pegs or furniture gliders. Here's why: If 60% of the weight is on the front wheels, the CoG is closer to the front wheels than the middle wheels. If the CoG is low enough that you are "not at major risk" of braking hard enough to tip forward, you are probably "at minimal risk" of ever needing to put weight on the rear wheels, and at "fuggetaboudit" for need to drive those rear wheels.

Interesting idea. From what I can tell, unpowered wheels used to be more common on early FRC drivetrains, but have fallen out of style in the past several years. It would probably work well in this case, but I do see one thing that might be a concern. In a six-wheel drop center (which might or might not be what we're talking about, I don't know 4587's robot), doesn't the robot tip backwards onto the back four wheels when driving forwards? Now I know that the position of the center of gravity affects the tilting of the chassis, but this would be on a case by case basis. If the chassis DOES tilt backwards when driving forwards, not powering the back wheels may make acceleration quite slow.