The way open carriers work is power goes to the side that has the least amount of traction. On a smooth dry road the least amount of traction is influenced by the torque of the motor twisting the body and raising the L rear and pushing down on the R rear. That is why typically the L rear spins. I believe that if you improve the grip on the side where the power is, the wheel that spins, you will simply send the power to the other side and that wheel will spin.