I was researching my spring issue on my 70 and found these 2 trw springs (cc501 and cs6319). opg sent me the 6319. trw site list the 6319 as a constate rate spring and the 501 as a variable. What is the difference. Im thinking that I should have got the 501 since my wheel well is sitting 4" above the tire

Variable rate springs are junk IMO, basically they wind a few coils real tight so that they actualy bind very quickly creating dead coils which increase the springs rate. Very difficult to tune a chassis with variable rate springs.

I guess they have a use in my grandpa's Oldsmobile 88 or something.

Okay, I wasn't sure if this would effect my stance or not.

Shouldn't based simply on variable vs, fixed rate. The variable spring may have a different spec height than the one have now....the back of the parts catalog will list them both.

Thanks Denny. Im waiting to here back from them. It looks like they sent me the wrong springs.

dennis68 has a definite bias towards racetrack performance. And when tuning the suspension for the track, you'll change springs like some folks change clothes. That's just part of the game.

For those of us on the street, variable rate springs (also called progressive or rising-rate) are a neat deal. Small bumps are absorbed by the softer coils, and so ride comfort is increased. Heavier bumps, or the load imposed by trailer towing or extra cargo (including people) are handled by the stiffer part of the spring, so as to help maintain ride height and prevent bottoming. You do have to have some thought to spring beginning and ending rate, and overall height of the spring-but it's not rocket science.

Any number of crotch rockets are designed to have rising-rate suspension. Even for performance applications, it can be done and done well.

if you are going to drive you car and have passengers variable rate springs are the ticket
if you are going to drag your car standard springs are the way to go
all depends on your application
I run variable rate springs and am very satisfied with the ride although I don't race anymore and normally just cruise

It's not just racetrack performance, suspension systems need to be tuned for the street too. Variable rates are a band-aid for vehicles that could be made to ride and perform well without them.

Go check under any new car.....how many progressive rate springs do you see?

dennis
I realize you know a ton of stuff about the tuning of these old cars
very good stuff too I might add
actually learned alot of neat stuff from some of the links you offered
there is no doubt you have this stuff nailed
still I like the variable rate springs under the convertable
I can put stuff in the trunk and have people in the back seat and the car only squats so far
(although this has not happened in two years since I ripped it down for the frame off)
I am not saying you are wrong because you are most probably not
just saying that there are options you can balance out for what your expectations are for the application you intend to run
I only putt around in the vert and actually like the variable rates better than the standard for the purpose of use on this car
the whole suspension is stock except fo the springs, large front swaybar, rear swaybar, gas shocks and fast ratio box
all just my preference and I do like the way it rides and handles for a low performance parade cruiser
if he is into performance you are the man around here though without a doubt

My car is basically going to be a weekend cruiser with some performance mods. suprisingly the company has not responded back to me about sending the wrong springs. The first thing I want to do is get the back end of the car back down with the right sized springs.

are you going to be letting people ride with you
are you going to have kinda big tires on it that might possibly hit the wheel wells
and maybe some stuff in the trunk
variable rate springs will let your car ride at the correct height when empty and will squat down only a small amount when loaded
these are some things to think about when replacing springs

Im running with standard size tires, 4 year old in the back seat and a spare tire in the trunk, so variable would probably work for me.