progressive vs. linear rate springs
 

i searched for quite a bit, and i can't believe that no one has ever directly compared progressive and linear rate springs! i don't know, maybe it has been, so please just tell me politely where to look...anyways, you can vote and give opinions on the two.

by the way, in case you guys are wondering on APPLICATION:

N/A s5 FC (89-91 rx-7), street driving on a variety of roads (bad to great), with autocross every second weekend

I have Racing Beat springs w/ Koni yellows and they're way to stiff for daily driving on Pittsburgh roads. We have some of the roughest roads around though. The setup would probably be great for autocrossing however.

Check this thread:
https://www.rx7club.com/showthread.p...ht=racing+beat

Tony

thanks for the reply zeravla.

okay, that thread is pretty useful, although it is mostly applicable to FD considerations, since i don't have the option of H&R springs (i don't think so anyways). also, i am surprised that 3/4 people have voted for linear rate springs so far. i have heard that the ride is harsh on public roads. i know they will be better over the progressive at the autox track, however like i said, it's only one day out of 14. i'm worried the other 13 days will be too rough for a stiff linear. i don't know, maybe it's not that hard of ride?

my other thought is that the eibach drop is too conservative, and i don't like how the front is dropped approx 1/4 inch more than rear. on the other hand, i do like the drop of approx 1 inch all around with the RBs. any thoughts on this?

what is the difference bewteen the two types?

anymore replies?

maybe on why everyone is voting for linear rate springs?

thank you for posting that thread it has excellent information.

Mitch

Well I have some experience with a well known German suspension supplier for European cars (VW's,Audi). Supplier is KW suspendions

http://www.kwsuspensions.com/


According to my knowledge the secret of the progressive aspect is the use of 2 springs per damper. Considering a complete coilover kit.

With 2 springs I mean a big spring with large radius+ smaller spring with shorter radius.

the thing is that, the lower you go, the wider the short spring gets. when totally up it's al thight, no use in fact. when lowering it opens, which results in a shorter damping strike but with few loss in comfort as it softens the shock.

example. We got into my friends VW Golf 2 G60, had a KW Variant 2 on it (height and hardness adjustable, KW uses always Koni Yellow for the Variant 2) and went for a ride.

Specs:
100mm lowered al round on 7.5X17's 205/40/17 Bridgestone Potenza's 01

We did thesame,familiar roads as I did with my car 60mm lowered al round with springs and shocks. so I knew where the hard parts were in our tour and where to look for problems or hard bumps.

We took of at cruisin speed. Car was really comfortable, at some point even better then my stock car. Even the ahrd bumps where my dash somethimes almost comes of the car, reallyw eher no problem. just a slight hobble and quickly back to consistent straight driving.

then we came to a viaduct. long straight line and then a long turn left wich could be taken at somewhat 80-90mph. straight line, again soft and easy suspension but ones you go into the turn and the cars gets a little roxk to the outher side you feel te suspension thighten up and get ridgid. realy if anybody had said this to me before I wouldn't have believed id, but it really did.

Conclusion. I became a dealer for the brand and there is nothing better.
even had them made a quote for my RX7 . 2018$ was the quote.

Still thinking about it but I think which way I"ll go.

Conclusion 2: if ou want it for daily driving or don't want to get freaking about bumping your head into the headpanel, be sure to get a kit with double springs per shock

Neal
sorry for the strange axplanation but i live in Belgium

Linear springs are a much better choice for any sports car. To me there really is no point to put a progressive spring on a sporty car because it really takes away from the feel of the car. Progressive springs are used mostly for luxury sedans to create a nice smooth ride. But they feel like shit when driven on the limit or when your trying to have fun with the car. Very sloppy feel, a little unpredictable because like speedworks mentioned they change rates halfway though the corner, and they do a good job of what it was designed to do, making the driver numb to the road. Which is exactly what you don't want in the sports car. All Racing cars use linear springs. If you ever get a chance I suggest that you test drive one car with and one car without. Unless your car is used only for cruzing around on the street, then a softer linear spring is better over a harder progressive IMO.

okay, thanks for the replies everyone.

it looks like people prefer linear rate springs, even for minimal on-track driving. i think i will go with linear rate springs with Koni Yellow shocks.

the racing beat springs seem to be the first choice for me. however, i am also looking at suspenion techniques linear rate springs. the thing i like better about the ST springs is that they have the same rate front and rear. apparently the RBs have a significantly lower rate in the rear than front. any thoughts on this?

just one remark about the pogressive setup with double springs (small and big spring)

you could take out the small spring and screw up the height adjuster bolts on the suspension leg.

Why?

You"ll create the possibility to go about 4 cm lower than with the small spring and only have the benefits of the big and stiffer spring.
It's up to you.

speedworks, thanks for the info. don't your drops seem pretty extreme, though? you were first talking about a 100mm drop, and that is 3 times more than the max i would drop. also, 4 cm ON TOP of whatever you are refering to is also lower than i would want...