Hi all, I've been reading up on ride rates and damping and am struggling to figure a few things out.
As far as I can understand, the 'ride frequency' of the vehicle is the *undamped* frequency that the body oscillates at when disturbed by bumps. We can tune this frequency to match a certain application (limo, performance street car, aero car etc), so that when the body is disturbed by the moving of the suspension over bumps, it oscillates only at this set ride frequency for the benefit of it's passengers.
Then what is it that affects the compliance of the tyre with the road? Is that what the damping does?
Lets say I have a really light car, and very stiff springs. The ground is bumpy (bumps are say 1mm in aplitude) and the car is going quite fast so the frequency of the bumps are say 40Hz. With no damping, will the very hard springs keep the tyre in contact with the road? I presume the problem with having such a high wheel rate is that the body will experience lots of shock and movement transmitted by the hard springs. In the same situation, but with very soft springs and no damping, will the tyre have improved compliance with the road, or will there be no difference?
I only ask because when selecting a ride rate, the only consideration seems to be driver comfort, and possibly the amount of travel you are limited to (according to Milliken). When selecting a ride rate, compliance with the road is never mentioned, and the only time I have seen the frequency of bumps in the road considered is when it comes to damping on a transmissibility graph, and that is still only for driver comfort as far as I can tell.
If anyone can add some information to try and make this clearer for me I would be very grateful.
As far as I can understand, the 'ride frequency' of the vehicle is the *undamped* frequency that the body oscillates at when disturbed by bumps. We can tune this frequency to match a certain application (limo, performance street car, aero car etc), so that when the body is disturbed by the moving of the suspension over bumps, it oscillates only at this set ride frequency for the benefit of it's passengers.
Then what is it that affects the compliance of the tyre with the road? Is that what the damping does?
Lets say I have a really light car, and very stiff springs. The ground is bumpy (bumps are say 1mm in aplitude) and the car is going quite fast so the frequency of the bumps are say 40Hz. With no damping, will the very hard springs keep the tyre in contact with the road? I presume the problem with having such a high wheel rate is that the body will experience lots of shock and movement transmitted by the hard springs. In the same situation, but with very soft springs and no damping, will the tyre have improved compliance with the road, or will there be no difference?
I only ask because when selecting a ride rate, the only consideration seems to be driver comfort, and possibly the amount of travel you are limited to (according to Milliken). When selecting a ride rate, compliance with the road is never mentioned, and the only time I have seen the frequency of bumps in the road considered is when it comes to damping on a transmissibility graph, and that is still only for driver comfort as far as I can tell.
If anyone can add some information to try and make this clearer for me I would be very grateful.