Speed limits and petrol consumption...

wolvoman

daveyjp said:

Its no different to pedalling a bike, cadence is key, keeping the pedals turning without using too much energy and you do this be selecting the right gear.p, too high or too low and your legs will let you know!

This.

It depends on a number of factors as well as such as road surface, slope, wind speed/direction.

Fuel use is directly based on throttle input. In too low a gear, your foot will go to the carpet without much resultant speed or acceleration and you'll be wasting a lot of fuel.