Spring Rates

[eliminator]

I've done a bit of research on springs to find out the spring rates for various kits.

-H&R sport (50800): 1.4"/1.3" lowering. According to the tech dept: "Rates increased 20-30% over stock." Which means nothing to me since I have no idea what the stock rates are, or if they mean stock base model, Touring, or GT.

-Gold Line (GPS-0300): 1.5"/2.0" lowering. F)160#. R) 160# variable rate. However, they didn't say what the beginning and ending rates are.

-Eibach Pro (2860.140): 1.6"/2.0" lowering. F)159# linear. R) 91-160# variable. According to Eibach, the rear spring is into the 160# rate at static ride height, so it basically functions as a 160# linear spring.

-Vogtland (950307): 1.4"/1.4" lowering. F) 168-230#. R) 138-285#

-Mopar stage 1: 1"/1" lowering. F) 200# linear. R) 185# linear

I crossed the H&R's off my wish list simply because they wouldn't tell me what the spring rates were. Gold Line and Eibach seem like a pretty soft rate for that much drop. Maybe that's why they work OK for some people with the stock shocks. I like the Vogtland's and Mopar stage 1's best because the rates are a bit higher, and they should be better able to keep the suspension off the bumpstops.

If anyone has more info, such as the stock spring rates, please post it.

-Steve

[Cal Cruzer]

quote:Originally posted by eliminator


I've done a bit of research on springs to find out the spring rates for various kits.

-H&R sport (50800): 1.4"/1.3" lowering. According to the tech dept: "Rates increased 20-30% over stock." Which means nothing to me since I have no idea what the stock rates are, or if they mean stock base model, Touring, or GT.

-Gold Line (GPS-0300): 1.5"/2.0" lowering. F)160#. R) 160# variable rate. However, they didn't say what the beginning and ending rates are.

-Vogtland (950307): 1.4"/1.4" lowering. F) 168-230#. R) 138-285#

-Mopar stage 1: 1"/1" lowering. F) 200# constant. R) 185# constant

I crossed the H&R's off my wish list simply because they wouldn't tell me what the spring rates were. The Gold Lines seem like a pretty soft rate for that much drop. Maybe that's why they work OK for some people with the stock shocks. I like the Vogtland's and Mopar stage 1's best because the rates are a bit higher, and they should be better able to keep the suspension off the bumpstops.

If anyone has more info, such as the stock spring rates, please post it.

-Steve

FWIW I got a little more drop than that from my H&R's

[Sci-Fi]

The 2003 PT GT stock spring rates are:
Front: 160 ln/in
Rear: 140 lb/in

[JohnM]

Great info Eliminator - thanks.

I have the Mopar springs on order, and it's great to get learn how they compare. (back ordered) I plan to pair the springs up with Tokico HP shocks. I don't think I will need to trim the bump stops with that setup.

BTW - I'd highly recommend the stock rear anti sway bar.

[Mike-in-Orange]

quote:eliminator Posted - 10/29/2004 : 4:02:17 PM
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-Gold Line (GPS-0300): 1.5"/2.0" lowering. F)160#. R) 160# variable rate. However, they didn't say what the beginning and ending rates are.

-Eibach Pro (2860.140): 1.6"/2.0" lowering. F)159# linear. R) 91-160# variable. According to Eibach, the rear spring is into the 160# rate at static ride height, so it basically functions as a 160# linear spring.

I have a new hero!! Thanks, this explains a lot. As Sci-Fi posted, if the stock spring rates are 160F/140R that probably explains why I had the rear end bouncing problem I did with the GoldLines and stock shocks, yet the front seemed fine. I'll just bet that the GoldLines start at 160 and get firmer from there, thereby compounding the problem. Probably also explains why people who have installed the Eibach springs aren't as bothered by the problem. If the Eibach rears are a pretty linear 160 then they aren't that far beyond factory, so the factory shocks can handle the task better. I would imaging that the factory shocks may have a shorter life with these springs, but hey, we'll all replace our shocks sooner or later, right?

Thanks guys! This is great information!