West Coast Drive vs Mini CIM Drive

[juju_beans]

They were 8in wheels, and the belts were tensioned I think.

[ThaddeusMaximus]

Something's clearly wrong.

If your gears are slipping, I'd recommend re-examining your gearboxes. Slipping gears isn't good. Also, don't run AM aluminum gears. They're made of much less hard material than Vex gears, so wear quite easily and eventually strip.

If your timing belt is slipping, you might be running C-C too far apart. (or maybe you should be upgrading from 9mm belt to 15mm? Would this help?)

These are much better options than decreasing your pushing power during a tip from 4 CIMs to 2 MiniCIMs. (When you chain your motors together, they can all contribute to motive power. When you don't, it's only the motors connected to wheels on the ground.)