Wheel size poll

[Richard Wallace]

Originally Posted by Lil' Lavery

8" IFI traction wheels x 4

As a rule of thumb, bigger wheels mean you can traverse more uneven terrain. Yes, this can be acheived other ways, but bigger wheels tend to save weight and complexity (think of the 2004 stairs for a perfect example).
Smallers wheels are lighter and take up less space (duh!), which leaves more space/weight for the rest of your robot.

Simple trade-off.

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.