impact of large/small steering wheels

Dear all,

Pls clarify what is the advanatage/ disadvanatage of a large steering (like in lorries, buses) versus smaller steering wheels like in cars?

thanks

big vehicles like in lorries, buses etc required higher torque (force x distance) hence they are equipped with larger steering wheels.

Plus a small steering wheel in a truck would probably not look good. However, speaking scientifically as Mayank said, its because a larger wheel allows greater torque at the steering wheel's centre - and this helps with both steering as well as somewhat cutting down on demands from the power-steering system (which basically means less chance of failure). However a larger wheel is harder to turn than a smaller one, in that it cannot be turned as fast as a smaller one.