[AustinSchuh]

How many teeth are on those sprockets? They look a bit small to me.

25 chain has a working strength of 140 lbs. Assuming a 16 tooth sprocket (guessing from your CAD...), that's 90 in-lbs of torque through the sprocket. A 150 lb robot with 4" wheels and a coeffecient of friction of 1.2 will have 150 in-lbs of torque applied to the set of wheels on each side before slipping wheels. That means that you can have 50% of the robot's weight on the front wheels before you exceed the working strength.

Lots of WCD use 22 tooth sprockets. (This is because the OD with chain is slightly under 2") That gives you a torque of 122 in-lbs. That means you can have 70% of the weight on the front wheels before you exceed the working strength.

I'd go with as big a sprocket as you can put on there before other things like clearance become a concern. Smaller will probably still work, but if you don't need them to be that exact size, make them bigger and give yourself a larger margin of safety.

How are you going to tension the chain? 25 chain stretches when used in a drivetrain, especially with small sprockets.

You might also want to add some cross-bracing to the frame, or mount the electronics panel more securely. A solid hit to the corners will put a lot of stress on the front and back 1x1's. At a minimum, add a 1x1 across the middle of the frame. I'd personally pull the electronics panel up to the bottom of the 1x1's and then bolt it securely to everything you can bolt it to. That will make the frame significantly more rigid. I would also think that the two 1x1 rails down the side will flex a little bit under normal loads. It would probably be worth it to put a plate across the middle near the middle wheel so you don't have to deal with the bearing sliding on the shaft, or in the hole.

Otherwise, it looks pretty reasonable.