# Which is more efficient: a larger wheel or a smaller wheel?

I'm designing a 2-wheeled cart that I plan to rig to a donkey for hauling work around a farm. I'm wondering if there are mechanical advantages to using smaller wheels (like 40 cm diameter) vs. using larger wheels (like 50 cm diameter).

• Bigger wheels will be less of a torture for the poor animal. After a stop, it is easier to start again walking, because the same force will do a higher momentum on the axis, thus making it easier to evince friction. It will be as well easier to walk over stones. May 30, 2013 at 21:12

I agree with @ja72 answer, except for what seems to me a minor slip (the kind I do all too often). I think he meant more energy to start or stop rather than more force, the same force for a longer time, or more force for the same acceleration.