Potomac-Greg

I currently have rear springs sized at 2.25" ID and 7" unloaded height. My ride height is pretty much stock (tbars are still in). I intend to pull the tbars and get 650# springs but I only have about another 1/2" of coilover thread to drop ride height. Is the solution as simple as getting 6" springs?

I realize that 1/2" drop at the coilover will be more drop at the tire (3/4"?), but the car has at least an inch to go before it's acceptable to me.

I wonder why Paragon Products only sells them with 7" springs?

Makis

I suspect you need 7" springs to avoid spring dislocation when the shock is fully extended. Also with the tbars ride height is controlled by tbars setting and coil over setting. When only using coilover setup you will need to do some calculations to work out what will be your minimum ride height. This should give you shock extension, which will then give you spring compressed length. With this information you can see if the 650# springs will be suitable. If not, you could opt for slightly softer springs. A two spring solution is also possible if you have to have 650# springs but then working out the correct setup is a bit more complicated.

Potomac-Greg

I already get spring dislocation with 7" springs. It makes for some noisy clanks and clunks. I could just get super-flat helper springs to take up the slack. The 650# is based on handling needs (I could go down to 600# but I don't think that will affect ride height much). The big unknown is how much removal of the stock t-bars will compress the 600-650# springs (further than the 450# springs are currently compressed.

Nader Fotouhi

7" is planty short enough. I run 8" with no effective rate from t/b and I have no issues with adjusting ride hieght.

Makis

I thought 7" are a bit short as I am using 8" springs but I don't have the same coilovers.

Don't see how you can use 650lb springs without dislocation and achieve the drop you are looking after. If my approximate calculation are right I expect the springs to just compress 2" in order to take the full weight of the car. To stop them dislocating the springs will have to be set quite high which will raise the car.

As you already have the 450lb springs you will be able to use them first to check how low you can get the car without dislocation.

Also you can still use the eccentric to get some more lowering adjustments if you need to fine tune things.

But at 650lb it looks like you will need the helper flat springs. Going any lower then 7" and you may run into the problem that the spring cannot take the full load of the car before is fully compressed.

Potomac-Greg

My mistake. On my rears, I have 250# 7" springs, in tandem with the t-bars. And I do not have dislocation sitting still/flat, only jacked up or over lateral humps.

So, the 250# springs are bearing weight. I've also got the eccentric dialed all the way down. My worry is that taking out the t-bars and replacing the 250# springs with 650 (or 600#) will be an increase in effective rate overall, and if I do not change the rear coilover perches, the rear will be higher than it is now. And if I want a lower ride height, I'll run out of threads. In a pinch, I suppose I could remove the upper ring that acts as the perch.