Assessing my Suspension

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[PJ Moran]

My whole car is "put together".  Nothing's stock or original.

The front suspension is the TCP coilover conversion with 350# springs.  TCP pushed me toward 400, but once they were installed, I felt they were too stiff, so they swapped me for 350's - still damn stiff - considering dropping to 300's.

Out back I have Flex-A-Form fiberglass springs.  The vendor offered 175 and 225 pound springs, and all but insisted I go with the 225's.  I think 175 is significantly stiffer than anything Ford put into a factory Mustang.  I'm considering changing to the 175's.

So, I now have a car that has a pretty stiff ride, and has mixed components front and rear.  How do I determine (short of destroying the car by finding the limits on the road) if my setup is "balanced" or "correct"?

I think everything's too stiff, but I can live with it as is.  I'm just concerned that the rears are too stiff for the fronts or vice-versa, if you know what I mean.  I think these high performance handling vendors err on the stiff side.  What's stiff to the typical driver is probably soft to them.  I think their recommendations are a bit biased to racing / track performance and not enough on "fun street".

????

[AzPete]

As far as "balanced" I would consider how the front and rear ride over the same set of RR tracks. If they both feel about the same harshness, I would say they match. If one is softer than the other, then work it the direction you desire, matching the soft or harsh ride.

[Shaun]

If you wanted to get really scientific about it you could measure all sorts of data points to figure out the f/r motio ratios and match the frequency f/r.  If you don't want or can't do all that then its going to be down to a seat of the pants test and tune.

Spring rate is only part of the 'stiffness' feeling.  Shock valving plays a huge roll in what you actually feel.  Something I think most manufacturers don't bother to figure out and just pick an off the shelf shock from a supplier and go with it.  There is an awful lot more to it than just picking something that fits and 'sort of feels right'.

I've heard time and time again guys complain about a dump truck stiff ride only to install a decent set of shocks with the same springs and the ride is totally transformed.

My vote would be to drive it around for a while.  If you don't like it start throwing money at it!

[PJ Moran]

The front shocks are TCP's singly adjustable Vari-Shocks set on the softest setting.  Out back I have KYB GR2's.  You can see that in both cases I'm going for "soft".

Shocks are supposed to dampen oscillations and keep the tire on the ground, not stiffen the ride.  If you want a stiffer ride, get stiffer springs.  That's my take on it, any way.

[AzPete]

How fast the shocks respond to the bounce is also part of the stiffness of the ride. Slower response....stiffer ride from what I think..