[Kevin Sevcik]

But Steve, weight shouldn't have any effect on your effective pushing ability to get you up the bump. What with the whole friction increasing in direct proportion to weight thing. Weight distribution may cause you problems if your CoM is too high or too far forward or rear.

I think the problem with the math is assuming 2848's robot is operating on a 45 degree incline. It's clearly never entirely on the 45 degree incline, so it never has to exert the theoretical .707 * mg force to keep it from sliding down the ramp. It always has a pair of wheels on the ground or the top of the platform, or straddling the bump. So it's never actually in a position that matches the physics land scenario of all four wheels on a 45.