Suspension Bump/Droop Travel

[260DET]

When setting up a strut suspended car for mostly sprints and driving to and from, what percentage of suspension travel should be given to bump travel?

I seem to recall that the rule of thumb is 2/3 bump, 1/3 droop but can't find any reliable reference to that. And while we are on the general subject, a lot of racing cars seem to have very little droop travel. What is the reason for that?

[Wojtek]

Hi Richard,
Rather then concentrating on a percentage, the actual amount of both bump and droop travel is more important. With bump, there needs to be enough to be able to absorb bumps in the road with both zore roll while driving straight ahead, as well as at the maximum body roll when cornering together with bumps. As for droop, it's similar to bump bum in reverse. The actual amount will depend on the car and the springs, sway bars and tires used, i.e.; the amount of bump and roll resistance and grip available.

Wojtek.

[260DET]

So why don't racing cars have much droop? Is it because their suspension is so stiff they get little body roll, because they don't want the unloaded wheel to play any part in suspending the car in that type of situation? Or????

[Wojtek]

Originally posted by 260DET
So why don't racing cars have much droop? Is it because their suspension is so stiff they get little body roll, because they don't want the unloaded wheel to play any part in suspending the car in that type of situation? Or????
as well as very low centre of gravity, very small roll moment, aerodynamic downforce rather then lift...