TJ Coil Info I had saved from other posts/sites etc..
For the TJ,
120's are standard,
160's are the upgrade (HD).
XJ's are 120,
MJ (Comanche pickup) is 140,
ZJ (Grand) are 200 front and 160 rear.
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Coil Spring rate formula is:
[11,250,000 x coil spring wire diameter^4] / [8 x # of active coils x avg. coil diameter^3]
COILS:
OEM XJ is supposedly 142-147 lb/in rate. 17" length 5.25" diameter
OEM ZJ with 4.0 is supposedly 190 lb/in rate front and rear.
OME 930 coils: 160 lb. spring rate. 1.75" of lift on XJ
OME 934 coils: 180 lb. spring rate.The 934 spring is 35 mm (1.37") longer than the 930 spring.
The 930 is listed as a XJ or ZJ I-6 spring and the 934 is listed as a ZJ V-8 spring but is also used on the XJ. the 934 should give about 2.5in lift.
Tera 4" TJ coils give 4.5" of lift on an XJ and have a 200 lb/in rate , 20.25" tall unloaded
Tera 3" TJ coils give 3.5" of lift on an XJ and have a 170 lb/in rate
RE 4.5in ZJ coils are 240 lb/in. give 6"-6.25" of lift on an XJ 22" tall unloaded
RE 5.5XJ coils are 4.5ZJ coils.
Rusty's 6.5" 22" long, 12 wraps of 5/16" stock
Rusty's 4.5" coils give 5" of lift and have a 150 lb/in rate, 22" tall unloaded
Rustys 3" coils give 3" and have 150 lb/in rate.
Rancho 3" coils, at least the old coils give about 2 1/4" of lift on an XJ and have a very high 235 lb/in rate.
rockkrawler 6.5" are 165 lbs/in
SJ 3" ZJ coils 218 lbs/in
SJ 6in XJ RR coil is 13 coils and same height and thickness as the RE ZJ4.5in XJ5.5in coil.
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Factory 6 cyl AT XJ Coil
Wire dia: .5"
Total Coils: 9 Active: ~8
Coil OD: 5.0"
Calc Spring Rate: 120 lb/in
Tested Spring Rate: 125 lb/in
Unloaded Height: 18.0"
Old man EMU
OEM Old man EMU XJ is supposedly 142-147 lb/in rate. 17" length 5.25" diameter
OEM ZJ with 4.0 is supposedly 190 lb/in rate front and rear.
OME 930 coils: 160 lb. spring rate. 1.75" of lift on XJ
OME 934 coils: 180 lb. spring rate.The 934 spring is 35 mm (1.37") longer than the 930 spring.
The 930 is listed as a XJ or ZJ I-6 spring and the 934 is listed as a
ZJ V-8 spring but is also used on the XJ. the 934 should give about 2.5in lift.
OEM is supposedly 147 lb/in rate. OME coils give 2.25" - 2.5" of lift and have a 148 lb/in rate
PORC-
XJ 6.5" 185 lbs/in (22.5" long)
Pro-Comp-
-Front Coils-
TJ 2" 170 lbs/in
TJ 4" 175 lbs/in
XJ 3" 230 lbs/in
XJ 4" 150-155 lb/in (19" Long) O.D. is 5.1" or 5.25"
ZJ 3" 220 lbs/in
RockKrawler-
XJ 3"
XJ 4.5"
XJ 6.5" are 165 lbs/in
XJ 8" are 176lbs/inch
Rubicon Express-
ZJ 4.5in coils are 240 lb/in. (22" tall long)
(RE 5.5XJ coils are 4.5ZJ coils.)
From Rubicon Express customer service email to T.N. (November 2004):
The 3.5" TJ fronts are approximately 240 pounds per inch. Uncompressed free length is 19"
The 4.5" TJ fronts are approximately 219 pounds per inch. Uncompressed free length is 19.75"
Rustys-
XJ 3" 150 lb/in rate.
XJ 4.5" 150 lb/in rate, 22" tall unloaded
XJ 6.5" 150 lb/in (22" long), 12 wraps of 5/16" stock
XJ 8.5-9" 180 lb/in
Rusty's says "Most of our spring are built to 180lbs. Our 4.5" leaves are built to 150lbs. as are our 300 coils. The 305 coil is set to 180lbs."
Sky Jacker-
ZJ 3" coils 218 lbs/in
Tera Flex-
XJ 3" TJ coils have a 170 lb/in rate
XJ 4" TJ coils have a 200 lb/in rate , 20.25" tall unloaded
From TeraFlex customer service email to T.N. (June 2004):
TJ springs
SR3T- Free length= 15" Spring rate= 190
SR4T- Free length= 15.38" Spring rate= 210
SF3T- Free length= 19.5" Spring rate= 170
SF4T- Free length= 20.25" Spring rate= 200
