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View Full Version : Anyway to determine spring rate without scales?


Hotwire
12-14-2023, 05:47 AM
Need to figure out what rear spring rate to go with, I can buy and swap springs but want to hopefully get close without a lot of purchasing involved.
Don't know of anyone in my area with scales besides the platform scale at the dragstrip, entry/exit is sloped so I don't think I could get accurate rear weight by parking just rear tires on it?

Just installed coilovers up front and am now realizing how soft the rear is w/ factory moog springs. I plan on getting adjustable shocks on the rear and aftermarket springs. Have rear coil spring setup and setting height is pretty simple, plus I'm running 3" exhaust, don't think I would have enough room for coilovers.
dhutton
12-14-2023, 06:31 AM
Can’t answer your question but I used UMI rear springs on my 64 A body with good results. I did end up raising the front on this car.

Don
Hotwire
12-14-2023, 08:17 AM
Thank you Don for the reply, pretty much the route I'll take. My front springs were sagging from beating on them, looked like yours, reason I opted for the coil overs, slapping myself for waiting so long.

https://flic.kr/p/2njnZ6d
dontlifttoshift
12-14-2023, 09:09 AM
Do you know the rate of the factory springs?
Hotwire
12-14-2023, 11:30 AM
The fronts were moog 6200, 290lbs/in
The rears are moog 6197, 138lbs/in

The front replacements are QA1 double adjustable with 450lbs/in springs. Looking to keep it from being a kidney beater but also be able to turn if that makes sense? Did an iron LQ4/t56 swap but set it back to the firewall to help with overall weight distribution. Doesn't help with the fuel tank out at the rear bumper though.
dontlifttoshift
12-14-2023, 01:12 PM
Approximately another 75 pounds in wheel rate in the front. 175-200 would be a decent stab at the rears......probably 175 if you want to consider the spring being behind the axle instead of in front/on top.
Hotwire
12-14-2023, 02:50 PM
Approximately another 75 pounds in wheel rate in the front. 175-200 would be a decent stab at the rears......probably 175 if you want to consider the spring being behind the axle instead of in front/on top.

Thank you, I greatly appreciate the advice!