kdgt500 wrote:

Has anybody on have any experience or knowledge on wether these are good buy or not?

there are a few different kinds . . some can make the ride a bit harsh when you hit a bump . . it would be better to know what you don't like about your current suspension so people can make suggestions.

a less progressive spring will give a better ride than a more progressive one . . eibach can make custom springs if you want.
 

kdgt500 wrote:

Right now the original springs are still on the car and I'm looking to freshen up the suspension this spring. I was wondering if somebody can fill me in on the pros and cons between these and a constant rate spring to help make a decision on what to buy.

i just gave you pretty much all the info there is.

a dual rate or progressive rate spring that has a small difference between the first and second rate will improve the ride slightly over pot holes.
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Last edited by barnett468 (1/20/2015 2:33 PM)

"Are they worth being over twice as much I wonder?"

nope


"So the only gain is it's not as sensitive to potholes?"

pretty much

you really need to simply tell us what you are trying to achieve and what you don't like about your stock suspension and what you do not want in ride performance if you want the best possible siggewstions/help.

basically, if you are going to drive your car on a motocross track or the off road world rallye circuit, you want progressive springs . . if you are not then you do not want them . . if you want a cadillac type ride you need to buy a cadillac etc.

   

Last edited by barnett468 (1/20/2015 2:55 PM)

kdgt500 wrote:

Naw, I'm not wanting it to ride like a cadillac and no I wont be racing it on track. I'll just be buzzing it up and down the backroads where I live at a decent clip. From what it sounds, I'd be better off with the constant rate spring.

if you are talking about dirt roads with small ripples and holes and bumps like firerpads that are periodically graded,  then high sidewall tires with slightly low air pressure will soften the ride but it will wallow a bit more in the higher speed turns and curves.

also shocks with progressive valving are good for this especially if the have adjustable damping . . viking shocks have adjustable compression and rebound damping but are 190.00 each . . konis are also good.

if it bottoms a bit too much now then buy 480 lb straight wound lowering springs or any spring from atpund 330 to 480 . . opentracker has some gt springs but they do not list the rate which seems useless to me . . if i dont know what im buying i aint gonna buy it so they are likely loosing sales due to this.
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Last edited by barnett468 (1/20/2015 3:14 PM)

What year car and what engine.  Answers will be different. Your name indicates big block?

My answers are from direct experience with small blocks, mainly 351w and an aluminum 427w engine.
I have used about every kind of spring on my 66 through the years.

By FAR, the best ride is with the Progressive Motorsports street version.

However, with the HP my car makes, it feels more confident handling with the track version, which still has a much better ride than any of the 600# lowering springs I have used. They also lower the car same as other "lowering springs".  Someday I will install another set of them. They are firm but not harsh.

My choice is the track version of the Progressive Motorsports springs.  When I first installed those, it was one of those WHERE HAVE THESE SPRINGS BEEN ALL MY LIFE? type moments.

For normal street use, the street version works really good. That is what I have right now.
Got them from Dr Gas.

Have tried the GT springs from Mustangs+.  They were ok as a stock replacement but they settled a WHOLE BUNCH, requiring repeated alignments as they settled deeper and deeper over a couple of years.

yes, the effect/ride is a bit different with them on different car weights.

Last edited by barnett468 (1/20/2015 7:52 PM)

Also, by the way it's a 67 coupe

My only experience with pro-rate springs was with a station wagon that occassionaly towed a heavy trailer. The single rate springs I initially installed on the rear were great for towing, but awful with no weight on the back. The pro-rate springs were perfect.
A coupla years ago, when I started accumulating parts for the front end overhaul, I researched pro-rate springs for the front of vehicles quite extensively. I justified the extra cost based on this research.
Unfortunately, I have yet to fit all the parts, so I can't give you any real world experience, but others can.
I'm confident I made the right choice for what I plan to use the car for.

Thanks Steve. I like the stance on that.

barnett468 wrote:

kdgt500 wrote:

Naw, I'm not wanting it to ride like a cadillac and no I wont be racing it on track. I'll just be buzzing it up and down the backroads where I live at a decent clip. From what it sounds, I'd be better off with the constant rate spring.

if you are talking about dirt roads with small ripples and holes and bumps like firerpads that are periodically graded,  then high sidewall tires with slightly low air pressure will soften the ride but it will wallow a bit more in the higher speed turns and curves.

also shocks with progressive valving are good for this especially if the have adjustable damping . . viking shocks have adjustable compression and rebound damping but are 190.00 each . . konis are also good.

if it bottoms a bit too much now then buy 480 lb straight wound lowering springs or any spring from atpund 330 to 480 . . opentracker has some gt springs but they do not list the rate which seems useless to me . . if i dont know what im buying i aint gonna buy it so they are likely loosing sales due to this.
.

An FYI, these GT springs from open tracker are the ones I was looking at for my 65, I was able to ascertain from OT that the springs are rated at between 280-300, I was planning on potentially using these in conjunction with the bilstein street valved shocks. 

Steve, I do like the stance on that mustang, in both pictures. To me, the differance between the two ride heights is negligable, noticable,  but they both look about where I would like mine to sit, also with a 235 45/17 sized tire.
 

So are we to assume all GT springs are the same? I dont know this is why I ask?

I am not sure about the progressive motorsports springs mustang Steve was talking about. I have had good experiences with the progressive springs that I got from pro motorsports engineering /Dr. Gas in sandy Utah. Back then, the springs were made by eibach....so, they may be the same as Steve was mentioning.  I went with the lighter springs 350-500 lbs. Combined with the negative wedge kit/Shelby drop, car rides and handles great. The car previously had mustangs plus 650 or 700 lb lowering springs, which handled better.....but rode like a dump truck. I like these progressives as you get a smooth ride but firm ness in corners. My car is a 67 cougar 289. If you choose to go with non progressive s, I recommend Detroit Eaton spring. They can make any spring for you, are very knowledgeable and their stuff is nice.