Coil spring letter codes and specs?

Does anyone have the specs (thickness, length, etc) for each letter code of coil spring? I'm looking for a match to a junkyard find and was unable to read the letter-code tag on it.

history... I found plenty of FJ springs at the junkyard which measure .52" thickness and approx 17" length. I also found one and a half springs on a 93 GC Laredo I6 that measured .56" thickness and approx 17" length. The tag was torn up but it kinda looked like FN or FM (definately F-something). If I had the spring specs, I could order a second spring to go with the one I found. As for the half... it was torched off when someone removed the front end.

The factory does not provide specs on the coil springs. There are so many different letter codes that it would be impossible (or nearly so) to get specs on every code that was available.

BTW -- wire diameter and free length are not the only specs you need. You also need the number of coils.

For the cost of one new spring at the dealer you could get 2 or 3 pairs from the junkyard. Just make another junkyard trip and get a pair from another Jeep. Coil springs codes that start with F are standard stock XJ and ZJ Grand springs. Coil codes that start with a G code are Up-Country springs on both XJ and ZJ's and will give about 1" lift and have a slightly higher spring rate making them a little firmer riding.

P/N 52001793 (code GK) is a 2000 XJ Up-Country coil
P/N 52008363 (code GN) is a ZJ Grand Up-Country coil.

Eagle said:

The factory does not provide specs on the coil springs. There are so many different letter codes that it would be impossible (or nearly so) to get specs on every code that was available.

BTW -- wire diameter and free length are not the only specs you need. You also need the number of coils.

Click to expand...

I understand. I did some more digging and figured out that the mystery spring I have only 1 of is a FN. .56 wd 9-coil. If I can't score another to match, at least I know what I can order from my local dealer. The application is actually to do a poor-man's lift on my pathfinder so my wife can go wheelin with me too. The coils on the rear of the pathy are .50wd and replacing them with the JGC springs will give about 3" of lift on the rear.

Thanks for the inputs.