[EricH]

Wait, what? Stop, think, RETHINK.

First, you're only dealing with a 2" platform. That's nothing. I've seen robots go up far steeper, far taller platforms. And if you're targeting the STEP, then you shouldn't be going on there at all. (And I'd still point out that I've seen robots climb that much of a step before.)

Second, the only thing worse than tank treads is >2 tank treads. Tank treads are notorious for breaking or for coming off at the least opportune time. Multiply by 2, and watch your problems multiply by at least 2.

Third, if your front treads go up the slope and the robot is still level, that means you've installed a suspension to KEEP it level. So you've got suspension problems on top of the tread problems (potentially).

Fourth, it's entirely possible to maintain control of a stack of bins without requiring the drivetrain to be level. For example, by building a cage around it.

My advice is simple: Start by building the KOP drivetrain. If you haven't done that yet, do it now. You'll be surprised just how easy it is to work with for building that perfect manipulator.