How light should I go with my flywheel? I realise that it depends on where you take off the material, but as a rough figure what would you say? SBD's sensible one is 5.4kg, the loony one is 2.1kg. I have heard of people who have done 3-3.5kg on a road car. Remembering I need to use the car everyday. would would you say would be the wieght to go for?