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Unread 09-24-2010, 09:02 PM   #1
the303hooligan
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1998 TJ Wrangler 
 
Join Date: Aug 2008
Location: Aurora, Colorado
Posts: 952
PRO-COMP Coil question

Anyone have a measurement of a 4" PRO COMP rear coil under compression on 98 tj?..(smittybilt bumper w/tire carrier w/ 35 on it) or close to same rear weight.. front coils seem to have correct measurement as a table floating around here, but rear is nowhere close to the # provided....AND i ask because rear seams to sag a bit more then possibly should...was planning on new coils all around then decided against it...but now the "visual non-level" effect is driving me up a wall....i have a bad "balance" OCD that is hard to live with sometimes...ha..any help would be greatly appreciated

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Colorado Jeep Club Member #'303'
1998 Jeep Wrangler TJ Sport 4.0 I6, D30 and D44,4.56 G2 Gears,belly,gas & steering skids, 35x12.5 Wrangler MTR Kevlars,4" ProComp Coils,1.25" JKS BL,1"Currie MML,Bilstein 5100's, Chromoly LCA's front and rear, JKS Disco's,K&N intake,PSC BFH front stinger bumper w/winch & d-rings,PSC Rear stinger/carrier w/d-ring,PSC Rocker Knockers,Dynomax Ultraflo welded ss, APN header,PIAA 520 ATP, Bestop top,alpine CDA-105 deck,Tuffy underseat Security box, JL Audio speakers in sound bar and dash, Corbeau front seats, matching Neoprene cover on bench,trimmed flares...and PLENTY more to come..
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Unread 09-24-2010, 09:16 PM   #2
bushusmarine
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1998 TJ Wrangler 
 
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Location: So Cal
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Sorry my jeep is on the other coast right now so no measurements. but i can tell you that i have a 98 tj with 33 baja claws and a spare on a rugged ridge tire carrier. i have the 4" pro comp coils and even with a portable tool box and full ice chest in the back it still sits level.
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Unread 09-24-2010, 09:35 PM   #3
TheDragonfly
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2001 TJ Wrangler 
 
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My rears were exactly 12" with stock bumper and 33" spare on the stock carrier with no backseat or passengers. Pro comps spring rate is around 175lbs per inch. So since you have two in series it takes 175lbs over stock weight to sag it about 1/2". How much does the smitty tire carrier weight?
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Unread 09-24-2010, 09:49 PM   #4
the303hooligan
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1998 TJ Wrangler 
 
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Quote:
Originally Posted by TheDragonfly View Post
My rears were pretty close to 12" with stock bumper and 33" spare on the stock carrier. Pro comps spring rate is around 175lbs per inch.
Ya, that what the table said they should be.....rear is "visually" a bit lower in back, when on flat surface...not much, but im thinking i may not have 4" coils in back OR they are sag'n ALOT..theres a 1/2-5/8" diff from top point of tires to bottom of fenders..front spring measures in at 16" and rear measures in at 11 1/4" ...not sure how long lift has been on, but all componets look good and un-aged looking..im guessing sag, but seems quite a bit for just tire n bumper...may be wrong tho...only delt with BDS lifts in the past...maybe a new set of 4" coils would bring me back to height? ...
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Colorado Jeep Club Member #'303'
1998 Jeep Wrangler TJ Sport 4.0 I6, D30 and D44,4.56 G2 Gears,belly,gas & steering skids, 35x12.5 Wrangler MTR Kevlars,4" ProComp Coils,1.25" JKS BL,1"Currie MML,Bilstein 5100's, Chromoly LCA's front and rear, JKS Disco's,K&N intake,PSC BFH front stinger bumper w/winch & d-rings,PSC Rear stinger/carrier w/d-ring,PSC Rocker Knockers,Dynomax Ultraflo welded ss, APN header,PIAA 520 ATP, Bestop top,alpine CDA-105 deck,Tuffy underseat Security box, JL Audio speakers in sound bar and dash, Corbeau front seats, matching Neoprene cover on bench,trimmed flares...and PLENTY more to come..
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Unread 09-24-2010, 11:14 PM   #5
TheDragonfly
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If your 35s are 67lbs, your rims are 28lbs, your bumper/tire carrier, is about 150 lbs, thats 248 extra pounds on your rear springs. You can calculate the deflected spring rate and it should be about 11.2914". Which is pretty close to 11 1/4" like you said. So you do have 4" springs with about 175lb spring rate. You wanted closer to 12" with that weight youll need to swap some 4" springs with more than 210lb spring rate. Or you can just add a 3/4" spacer.
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Unread 09-26-2010, 05:03 PM   #6
the303hooligan
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Quote:
Originally Posted by TheDragonfly View Post
If your 35s are 67lbs, your rims are 28lbs, your bumper/tire carrier, is about 150 lbs, thats 248 extra pounds on your rear springs. You can calculate the deflected spring rate and it should be about 11.2914". Which is pretty close to 11 1/4" like you said. So you do have 4" springs with about 175lb spring rate. You wanted closer to 12" with that weight youll need to swap some 4" springs with more than 210lb spring rate. Or you can just add a 3/4" spacer.
THANK YOU! Looking into new coils this weekend...just at a stuck point..between trying AEV over the Currie HD and RE...not sure what i should do...
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Colorado Jeep Club Member #'303'
1998 Jeep Wrangler TJ Sport 4.0 I6, D30 and D44,4.56 G2 Gears,belly,gas & steering skids, 35x12.5 Wrangler MTR Kevlars,4" ProComp Coils,1.25" JKS BL,1"Currie MML,Bilstein 5100's, Chromoly LCA's front and rear, JKS Disco's,K&N intake,PSC BFH front stinger bumper w/winch & d-rings,PSC Rear stinger/carrier w/d-ring,PSC Rocker Knockers,Dynomax Ultraflo welded ss, APN header,PIAA 520 ATP, Bestop top,alpine CDA-105 deck,Tuffy underseat Security box, JL Audio speakers in sound bar and dash, Corbeau front seats, matching Neoprene cover on bench,trimmed flares...and PLENTY more to come..
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Unread 09-29-2010, 05:51 PM   #7
the303hooligan
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So, i talked to rep at AEV about new 4.5" coils...BUT after talking to him,he said that they ride at 11" under regular load...thats .25-.50 shorter then what i currently have...seems alot of $$ to ride at a lower height...but maybe im missing something about them...anyone run these and can give me a coil measurement with their TJ on a flat surface?..(front and rear).....

2nd part of the question is, what if i go with RE 4.5SF coils?...seems that would put me a bit higher and have that added spring rate...if i were to go with that, would anything need to be adjusted by making a .5-.75 increase in height? ....... sorry for long question, but need sum advise on any GOOD 4" coils or RE4.5" option...the visual "sag" i see everyday is driving me nuts..
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Colorado Jeep Club Member #'303'
1998 Jeep Wrangler TJ Sport 4.0 I6, D30 and D44,4.56 G2 Gears,belly,gas & steering skids, 35x12.5 Wrangler MTR Kevlars,4" ProComp Coils,1.25" JKS BL,1"Currie MML,Bilstein 5100's, Chromoly LCA's front and rear, JKS Disco's,K&N intake,PSC BFH front stinger bumper w/winch & d-rings,PSC Rear stinger/carrier w/d-ring,PSC Rocker Knockers,Dynomax Ultraflo welded ss, APN header,PIAA 520 ATP, Bestop top,alpine CDA-105 deck,Tuffy underseat Security box, JL Audio speakers in sound bar and dash, Corbeau front seats, matching Neoprene cover on bench,trimmed flares...and PLENTY more to come..
**Oil Field Trash Makin' Oil Field Ca$h**
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