How does one figure which spring rate to use on any given car?

For instance, if your car weighs 3000lbs, and it's a 60-40 weight, how do you figure which springs to use?

Or, is it just an educated guess?

TIA

 

Best to find out what other people using the same car for the same purpose are using..

The reason I say this is that suspension geometry can change the effective "wheel rate" or spring rate at the wheel, for a given spring. On a Honda civic, a 1000 pound spring is rattle your teeth on the street, but due to mustang suspension geometry, it's not really a big deal (if I remember my facts correctly).

Also, obviously, FWD vs. RWD matters too..

and again, obviously, it depends on the application (road race, daily driver, performance rally, autocross)

In the end, the answer to your question for most people is "educated guess with trial and error" (hopefully you can make use of other people's trial and error). That said, the "learn from what other people do" tactic is probably much more sane when you get to the world of competition drivers, as opposed to the "Yo! TiZzItE! ShIzNiT!" crowd. In the competition crowd, you can evaluate their skills and their performance with their car to get an idea of their credibility.

 

to get the best rates it's ultimately trial & error and datalogging/checking the results and driver's feedback.

you have to specify the general environement to start with to get into the ball park.
bump or smooth track, what type of tires, any down force, type of racing... etc. and work from there.

 

Ok, well here's my thoughts. I mostly drive on the streets, but I love to hit the local mountians and tear up some asphault. I intend on going to some track days here in SoCal when they open.


About my car-

95 Civic coupe hybrid GSR.
LSD equipped tranny
24mm front bar (soon to be 26 if necessary)
22mm rear bar
all energy suspension bushings


I'm considering these 2 spring rates.

F- 448
R- 280

Or

F- 448
R- 336

I can also do...
F- 392
R- 168

But I think that's too soft of a spring.

Any recommendations?


[Modified by B18C-EJ1, 11:21 AM 2/6/2002]

 

If you are SERIOUS about it,I would get the car "corner weighted." You've obviously made some driveline changes that will have effectively changed the stock suspension geometry anyway.

My buddy Loren just installed a FULL Penske adjustable system on his car,somewhere around $10k?

But he can change virtually every aspect of the suspension now.

I usually go with a harder than normal spring rate and use a slightly softer dampner setting,it helps offset the "bone chattering" associated with stiffer spring rates.

 

I can tell you I'm very happy with my budget setup. Rides firm on the streets, but still comfy. And works quite well on the track. Even pro driver Rhys Millen had compliments for it, noting only lack of power, it is just a 1.6 after all. But it holds it own quite well.

http://g-speed.com/eg2/mods

 

Well,I'll say this,for MOST applications,a budget street set-up is more than enough.

You'd just have to know Loren to see why spending $10k on his SoloII Miata,sounded like a good idea. He never half way does anything.

I am from the school of thought, "do only as much is nescessary." This way you're not to broke to go celebrate afterwards. lol