40" how too
Thread Starter
JK Newbie
Joined: Nov 2007
Posts: 3
Likes: 0
From: Edmonton Alberta
40" how too
Hey guys new to this site. I am awaiting delivery of my 08 rubicon unlimited and doing some reserch on what I need to do to fit 40's under this thing any help would be appreciated. P.S. great site !
JK Freak
Joined: Jan 2007
Posts: 516
Likes: 0
Well....if it were me, i would personally go with a currie rock jock suspension lift, 1" body lift, Flat fenders from PJ or the like, new drive shafts from JE real etc...1350s front and rear, new axles dana 60s front and rear with a spool both front and rear or call up sunray engineering, they are awesome, 5:38 gears, atlas 2 transfer case, hmm....cant think of anymore at the moment but that should keep you busy for a while.
o, thats also about...30k worth of stuff
do you want to wheel it, or is it a street queen
o, thats also about...30k worth of stuff
do you want to wheel it, or is it a street queen
JK Freak
Joined: Dec 2006
Posts: 947
Likes: 0
From: Cleveland, Ohio
wow 40" tires would be amazing, basically here is my opinion on what you'll need, for starters, a whole bunch of money, 
sorry i had to do it. Seriously though, its not going to be cheap, the tires alone are going to cost a fortune, but i assume you already know that. so here is what i would do, or at least start with
I would go with a full traction 6" long arm kit and add a 2" budget boost on top of that along with 3/4" front leveling spacers. In the rear, would fabricate something to permanently affix the budget boost spacer into place for added peace of mind while wheeling. On top of that, i woul also add a 1" body kit. totalling 9" of lift. you're going to need all new drive shafts and all new extended brake lines at each corner. if you'll be running a spare, you undoubtedly going to need a new bumper is swing out tire carrier. and a stubby front bumper as well. Trim the pinch seam at the wheel wells as much as you can and i don't know which tires you'd be running, but i would try to stay at 4" backspacing. dana 60s would be the way to go. the 44s might hold up if you baby them but i personally beat up on my jeep and i know i would put dana 60s under that thing. as for gearing, 5:38 gears, but unless you go to a dana 60, 5:13s will be your limit anyhow. a 5.7 or 6.1 liter hemi would also make the list. The 3.8 isn't horrible, especially with the proper gearing, but 40" is a lot of tire
and you'll also need to look into steering geometry. at that much lift i would say a dropped pitman arm in combination with front and rear frame mounted trac bar drop brackets and adjustable trac bars would be a good place to start, but a high steer set up would be ideal.
as for shocks, with the added 2" budget boost, you could use shock extensions if you want to keep the shocks you just paid so much money for in the 6" kit, or buy some longer shocks. extensions would be a lot easier to come by than shocks designed for 8" of lift on a JK, but if money is no issue i would reccomend the longer shocks.
now some might say that i've recommended more than enough lift, but like i said, thats how i would do it, and i like room in the fenders especially with bigger tires. You could go with some flat top fenders to help fit the tires with less lift, but i personally like the look of the stock fenders and would rather have the added lift, Good luck and i certainly hope you do this and post pics.
If i missed anything, i hope others will be able to point it out for you. again good luck
sorry i had to do it. Seriously though, its not going to be cheap, the tires alone are going to cost a fortune, but i assume you already know that. so here is what i would do, or at least start withI would go with a full traction 6" long arm kit and add a 2" budget boost on top of that along with 3/4" front leveling spacers. In the rear, would fabricate something to permanently affix the budget boost spacer into place for added peace of mind while wheeling. On top of that, i woul also add a 1" body kit. totalling 9" of lift. you're going to need all new drive shafts and all new extended brake lines at each corner. if you'll be running a spare, you undoubtedly going to need a new bumper is swing out tire carrier. and a stubby front bumper as well. Trim the pinch seam at the wheel wells as much as you can and i don't know which tires you'd be running, but i would try to stay at 4" backspacing. dana 60s would be the way to go. the 44s might hold up if you baby them but i personally beat up on my jeep and i know i would put dana 60s under that thing. as for gearing, 5:38 gears, but unless you go to a dana 60, 5:13s will be your limit anyhow. a 5.7 or 6.1 liter hemi would also make the list. The 3.8 isn't horrible, especially with the proper gearing, but 40" is a lot of tire
and you'll also need to look into steering geometry. at that much lift i would say a dropped pitman arm in combination with front and rear frame mounted trac bar drop brackets and adjustable trac bars would be a good place to start, but a high steer set up would be ideal.
as for shocks, with the added 2" budget boost, you could use shock extensions if you want to keep the shocks you just paid so much money for in the 6" kit, or buy some longer shocks. extensions would be a lot easier to come by than shocks designed for 8" of lift on a JK, but if money is no issue i would reccomend the longer shocks.
now some might say that i've recommended more than enough lift, but like i said, thats how i would do it, and i like room in the fenders especially with bigger tires. You could go with some flat top fenders to help fit the tires with less lift, but i personally like the look of the stock fenders and would rather have the added lift, Good luck and i certainly hope you do this and post pics.
If i missed anything, i hope others will be able to point it out for you. again good luck
Last edited by yellowjeeper85; Jan 6, 2008 at 09:17 PM.
Thread Starter
JK Newbie
Joined: Nov 2007
Posts: 3
Likes: 0
From: Edmonton Alberta
Hey thanks for the help guys. I plan on it being a DD as well as light to moderate trail use, then upgrade and wheel harder as it gets older. Currently I am wheeling a cherokee whith 9" custom suspension and I have a spare set of 39.5" iroks that I would like to use.
Current items
-39.5 Iroks
-5.13 gear set
-9.5ti
-more 1" body lift
-zenon flat flares
items to get
-considering FT 6" long arm
-pro rock 60's (down the road)
thanks guys
Current items
-39.5 Iroks
-5.13 gear set
-9.5ti
-more 1" body lift
-zenon flat flares
items to get
-considering FT 6" long arm
-pro rock 60's (down the road)
thanks guys
JK Junkie
Joined: Jun 2007
Posts: 3,016
Likes: 2
From: apollo beach, fl
Hey thanks for the help guys. I plan on it being a DD as well as light to moderate trail use, then upgrade and wheel harder as it gets older. Currently I am wheeling a cherokee whith 9" custom suspension and I have a spare set of 39.5" iroks that I would like to use.
Current items
-39.5 Iroks
-5.13 gear set
-9.5ti
-more 1" body lift
-zenon flat flares
items to get
-considering FT 6" long arm
-pro rock 60's (down the road)
thanks guys
Current items
-39.5 Iroks
-5.13 gear set
-9.5ti
-more 1" body lift
-zenon flat flares
items to get
-considering FT 6" long arm
-pro rock 60's (down the road)
thanks guys
JK Junkie
Joined: Dec 2006
Posts: 3,130
Likes: 2
From: Highland, Utah
wow 40" tires would be amazing, basically here is my opinion on what you'll need, for starters, a whole bunch of money, sorry i had to do it. Seriously though, its not going to be cheap, the tires alone are going to cost a fortune, but i assume you already know that. so here is what i would do, or at least start with
I would go with a full traction 6" long arm kit and add a 2" budget boost on top of that along with 3/4" front leveling spacers. In the rear, would fabricate something to permanently affix the budget boost spacer into place for added peace of mind while wheeling. On top of that, i woul also add a 1" body kit. totalling 9" of lift. you're going to need all new drive shafts and all new extended brake lines at each corner. if you'll be running a spare, you undoubtedly going to need a new bumper is swing out tire carrier. and a stubby front bumper as well. Trim the pinch seam at the wheel wells as much as you can and i don't know which tires you'd be running, but i would try to stay at 4" backspacing. dana 60s would be the way to go. the 44s might hold up if you baby them but i personally beat up on my jeep and i know i would put dana 60s under that thing. as for gearing, 5:38 gears, but unless you go to a dana 60, 5:13s will be your limit anyhow. a 5.7 or 6.1 liter hemi would also make the list. The 3.8 isn't horrible, especially with the proper gearing, but 40" is a lot of tire
and you'll also need to look into steering geometry. at that much lift i would say a dropped pitman arm in combination with front and rear frame mounted trac bar drop brackets and adjustable trac bars would be a good place to start, but a high steer set up would be ideal.
as for shocks, with the added 2" budget boost, you could use shock extensions if you want to keep the shocks you just paid so much money for in the 6" kit, or buy some longer shocks. extensions would be a lot easier to come by than shocks designed for 8" of lift on a JK, but if money is no issue i would reccomend the longer shocks.
now some might say that i've recommended more than enough lift, but like i said, thats how i would do it, and i like room in the fenders especially with bigger tires. You could go with some flat top fenders to help fit the tires with less lift, but i personally like the look of the stock fenders and would rather have the added lift, Good luck and i certainly hope you do this and post pics.
If i missed anything, i hope others will be able to point it out for you. again good luck
sorry i had to do it. Seriously though, its not going to be cheap, the tires alone are going to cost a fortune, but i assume you already know that. so here is what i would do, or at least start withI would go with a full traction 6" long arm kit and add a 2" budget boost on top of that along with 3/4" front leveling spacers. In the rear, would fabricate something to permanently affix the budget boost spacer into place for added peace of mind while wheeling. On top of that, i woul also add a 1" body kit. totalling 9" of lift. you're going to need all new drive shafts and all new extended brake lines at each corner. if you'll be running a spare, you undoubtedly going to need a new bumper is swing out tire carrier. and a stubby front bumper as well. Trim the pinch seam at the wheel wells as much as you can and i don't know which tires you'd be running, but i would try to stay at 4" backspacing. dana 60s would be the way to go. the 44s might hold up if you baby them but i personally beat up on my jeep and i know i would put dana 60s under that thing. as for gearing, 5:38 gears, but unless you go to a dana 60, 5:13s will be your limit anyhow. a 5.7 or 6.1 liter hemi would also make the list. The 3.8 isn't horrible, especially with the proper gearing, but 40" is a lot of tire
and you'll also need to look into steering geometry. at that much lift i would say a dropped pitman arm in combination with front and rear frame mounted trac bar drop brackets and adjustable trac bars would be a good place to start, but a high steer set up would be ideal.
as for shocks, with the added 2" budget boost, you could use shock extensions if you want to keep the shocks you just paid so much money for in the 6" kit, or buy some longer shocks. extensions would be a lot easier to come by than shocks designed for 8" of lift on a JK, but if money is no issue i would reccomend the longer shocks.
now some might say that i've recommended more than enough lift, but like i said, thats how i would do it, and i like room in the fenders especially with bigger tires. You could go with some flat top fenders to help fit the tires with less lift, but i personally like the look of the stock fenders and would rather have the added lift, Good luck and i certainly hope you do this and post pics.
If i missed anything, i hope others will be able to point it out for you. again good luck
I concur.
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JK Enthusiast
Joined: Dec 2006
Posts: 132
Likes: 0
I've seen several 4 door JK's on 40's.
I run 37's with about 4-5 inches of lift(skyjacker long arm), no rubbing(after cutting the rocker bars). D-44's are holding up very well. Tom Woods shafts, etc. I would only need about 1 to 2 inches of additional lift to run 40's, however, the drive train would start to suffer.
I wheeled with another JK with the 6 inch skyjacker long arm kit and a 1 inch spacer. the spacer was added in due to the extra weight in the winch and bumpers, spare tire, etc.
With that much lift, he was clearing 40 inch BFGkm2's with no problems. The rear fenders were trimmed a bit but not much.
You main concern going to 40s on a JK should be axles and the rest of the drive train.
I run 37's with about 4-5 inches of lift(skyjacker long arm), no rubbing(after cutting the rocker bars). D-44's are holding up very well. Tom Woods shafts, etc. I would only need about 1 to 2 inches of additional lift to run 40's, however, the drive train would start to suffer.
I wheeled with another JK with the 6 inch skyjacker long arm kit and a 1 inch spacer. the spacer was added in due to the extra weight in the winch and bumpers, spare tire, etc.
With that much lift, he was clearing 40 inch BFGkm2's with no problems. The rear fenders were trimmed a bit but not much.
You main concern going to 40s on a JK should be axles and the rest of the drive train.