Wheel size poll

[Lil' Lavery]

Originally Posted by Richard

Maybe not that simple.

Assuming equal motors, faster robots don't push as hard. So no matter what wheel diameter you choose, you still have the basic speed vs. force trade-off to consider. You find your own optimum solution by selecting your gear ratio (or ratios in the case of a shifting system) and your wheels.

8" IFI traction wheels will need about twice the gear ratio that 4" IFI traction wheels need, to get to the same speed and force. If your speed reduction system gets larger or heavier, or less efficient, because of the higher ratio, then you'll need to consider that trade-off against the benefit of larger wheels.

As always, the right answer depends on the game.

I was assuming that you'd adjust the drive shaft rpm to match speeds, as I was purely comparing wheels, not entire drivetrains. Yes, wheels essentially act as the final gearing on the shaft, and you must adjust the shafts rpm to match your desired speed/torque. But you have to do that no matter what wheel size you chose.