Spring rate question
10-24-2007, 04:41 AM
#1
Burning Brakes
Thread Starter
Spring rate question
In reading pages of info on spring & shock upgrades, I came across the following reference which I found very helpful and confusing at the same time.
Given that factory / stock front spring rates for post-'91 964 & 965 are @169 and the only difference on rear spring rates exists only between 964 NB and 965/M030/RSA, why does the aftermarket springs have much higher front rates on RSA and Turbo? I would have imagined the aftermarket spring rates for turbo and non-turbo to be nearly the same, while the rear carry a much higher spring rate to maintain overall F-R rate ratio. This got me to wonder if it is logical to use H&R green front and H&R rear to maintain factory balance and to possibly find a happier compromise for the street between softer greens & turbo reds.
Since I really don't have much knowledge on springs & suspension upgrades for 964/965 other than taking out my Visa card, I hope to make a more informed decision before the upgrade.
Code:
Lowering Springs - Progressive Rates C2/C4 front 190-225 rear 220-265 RSA front 250-275 rear 270-295 Turbo front 230-265 rear 280-320 Coilovers - Progressive Rates C2/C4 front 250-270 rear 265-285 year 89-90 C2/C4 front 250-285 rear 265-285 year 91-94 Turbo front 260-285 rear 275-320 Stock spring rates ** 89-91 C2/C4 front 158 rear 189 92-94 C2/C4 front 169 rear 189 91-94 Option M030 front 169 rear 263 93-94 RS America front 169 rear 263 91-92 Turbo 3.3 front 169 rear 263 1992 Carrera RS (European) front 247 rear 440 Progressive Rate 1992 Carrera Cup USA front 247 rear 440 Progressive Rate Carrera Cup Racing Car front 200-600 rear 240-800 Progressive Rate
Since I really don't have much knowledge on springs & suspension upgrades for 964/965 other than taking out my Visa card, I hope to make a more informed decision before the upgrade.
10-24-2007, 10:45 AM
#2
Addict
Rennlist Member
Rennlist Member
why does the aftermarket springs have much higher front rates on RSA and Turbo? I would have imagined the aftermarket spring rates for turbo and non-turbo to be nearly the same, while the rear carry a much higher spring rate to maintain overall F-R rate ratio. This got me to wonder if it is logical to use H&R green front and H&R rear to maintain factory balance and to possibly find a happier compromise for the street between softer greens & turbo reds.
As for mix and matching H&R spring pairs, I believe they only sell them in sets of four (someone, feel free to correct me if I'm wrong). But what it really comes down to is What is it you're after? If it's ride comfort, I can tell you that going from the stock linear springs to progressive rate aftermarkets is a pleasant surprise. While the max spring rates may be higher, IMHO, the progressive design provides a less jarring ride than the stock coils.
Make sure you consider upgrading the shocks at the same time (if your car still has the stock parts). Not only is the expense of installing, balancing and aligning your car something you want to experience as infrequently as possible, you'll also be robbing yourself of one of the best upgrades for your car--new springs and shocks. The transformation will be nothing short of miraculous.
Last edited by joey bagadonuts; 10-24-2007 at 11:08 AM.
