thoughts on spring rates

[Black95TSIawd]

I know this may not be a good comparison, but its worth a shot for discussion.

Evo tuners and suspension shops attack spring rates in a completely different way than we do with our DSM's. It seems that any good evo coilover kit has either identical or stiffer spring rates out back and i've read numerous posts on evom.net that any coilover designed with less spring rate out back is not worth it.

Now, in the DSM's case, we seem to tighten up the front but never really go past the 350 to 400 rates out back and never have less rate up front.


The DSM and evo are both AWD and have a similar weight bias so why so different with the suspension setup? I would assume that having the rear a tad stiffer could help the car rotate a bit better. Thoughts?.....

And please, only educated posts. If you don't have a clue as to what i'm talking about, don't post. Also, names like JIC, Tein, and Megan Racing are crappy coilovers in the evo world. I'm talking big names like Robispec, JRZ, Eibach, yes eibach coilovers, have their design the way i'm describing. You usually don't see these on drag cars, but big time on the road race/time attack cars.

 

[ACM]

The spring rates are different because the suspension design is completely different between 2Gs and 1G/Evo.

2G front suspension design gives a .75 motion ratio, and .8 in the rear. 1G/Evo front suspension design results in a .95/1.0 motion ratio. I can't quote the rear of a 1G or an Evo because I don't know it - the front is easy because it's a McStrut, so the motion ratio has to be within a whisker of 1.

2Gs are also 200+ pounds lighter, have a lower CG and a more stable roll axis, the lack of which conspire against the Evo.

We are all attacking spring rates in the same way (assuming intelligently researched) - we're all working on the wheel rate, not the spring rate. The wheel rate is all that matters, the spring rate simply incidental.

Charles

 

[Black95TSIawd]

How does motion ratio affect spring rate? And, can you explain wheel rate vs spring rate? I've never heard that term.