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ZONE 4.25" combo lift for TJ available at Rockridge4wNEW!! HMF 50"-52" light bar mounting brackets!! SPARTAN LOCKERS are on sale BIG TIME at ROCKRIDGE 4WD!

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Unread 01-04-2009, 10:12 AM   #1
planman
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Info for going to 35" tires on a JK

JK Lift, Gearing, Skidplate, Tire, & Wheel Considerations

Build for 35” Tires (Budget is $2,500+)

LIFT CONSIDERATIONS (Budget is $400+)







Minimum 2.5” lift (1” body lift and/or flat/trimmed flares add more room)
Spacers or taller springs
Longer rear swaybar links (move stock rears to front)
Rear trackbar or trackbar relocation bracket
Extended bumpstops (fronts not required if you go with flat/trimmed flares)
Rear extended brakeline bracket (easy to fab if not in your kit) or longer brakelines
At 3” you will want an adjustable front trackbar.
Over 3” you will want adjustable lower control arms and an adjustable front trackbar.
If you add a heavy front bumper/winch, you will need a 0.75” front spring spacer to level the JK.
At 3” a 2 dr should consider a rear driveshaft, at 4” a 4dr should consider one due to steep driveshaft angles causing failures.
Lifted JK's with automatic transmissions may have stock driveshaft clearance problems with their stock automatic transmission skid and with their transmission case.
The Rubicon stock shocks are high quality. So, Teraflex and Rough Country sell kits with shock extensions.
Teraflex:
(Teraflex lifts include longer swaybar links, rear trackbar bracket, & extended bumpstops)
2.5” Budget Boost spacer lift with shock adapters is about $249, or $395 with shocks
2.5” Spring lift with shock adapters is $440, or $600 with shocks
3” Spring lift with shocks is $829, (higher than 2.5” lift and you will want to add an adjustable front trackbar from JKS for $140)
Rough Country:
2.5” Spring lift with shocks is $329 plus shipping, but you will want longer swaybar links ($40), rear trackbar relocation bracket ($40), extended bumpstops ($75), and rear brakeline relocation brackets for a total of about $500 shipped.
Superlift, Black Diamond, Zone, and others are similar. Just be sure you have all the components.

Performance Accessories or M.O.R.E: 1” body lift is about $100-$150

Xenon: Flat flares are about $500-$550 depending upon whether you go narrower or wider than stock.


GEARING (Budget is $380 for Programmer, Add $1500 to re-gear)

With taller tires, you may want to add a Hypertech Programmer for about $380 to modify your tune, and to adjust for different size tires and gears. The stock gears are bearable with 35s, a Programmer, and turning off the Overdrive on an automatic or not using 6th gear on a 6 speed.

With an Automatic, 5.13 gears are best for 35”+ size tires.
With a 6 speed, 4.88 gears are best for 35” tires and 5.13 gears for 37”+ size tires.
Superior Axle Gears with overhaul kits run about $700.
American Expedition Vehicles in Missoula will do the gear install for about $800 for labor.



SKID PLATE CONSIDERATIONS (Budget is $480+)

The stock automatic transmission skid plate can cause driveline clearance problems when an automatic JK is lifted. There is no stock engine skid plate. The stock gas tank skid plate is thin.

The stock rocker guards/sliders are strong enough to support the jeep.

Minimum recommended skid plate is the Rock Hard engine skid for $380, and EVAP canister skid for $100

TNT Customs/TREKS is selling their combo engine, transfer case and gas tank skid system for $1000

Front and rear bumpers are expensive and start at about $1000 for the pair.

Running a larger than 35” on the stock tire carrier is not advisable.


TIRE CONSIDERATIONS (Budget is $400+ for spacers or wheels and $1200+ for tires)

The stock wheels are narrow with significant backspacing. In order to run wider than a stock tire on the stock wheels, wheel spacers from Teraflex or Spidertrax are necessary to avoid tire damage due to rubbing on suspension components. The spacers are about $100 a pair.

Aftermarket wheels should have no more than 4.5” backspacing. The JKs 5x5 bolt pattern is different than the TJ (5x4.5).

If you sell your stock tires and wheels, you may be able to get $500-$700 for them to offset the cost of larger tires and wheels.

Some 15” wheels may rub the front calipers—requiring grinding some of the material off the calipers for clearance. Most 16” and 17” wheels with 5x5 bolt patterns and 4.5” or less backspacing fit with no problems.

Costco is the least expensive place to buy BFG KM2s. You have to special order them. They mount them to your wheels for carry out. They will not install the tires/wheels on your jeep.

Discount Tire is also extremely compeititve in pricing and service.

Tires for 16” or 17” wheels cost about $80-$100 more per tire than for 15” wheels.


Notes:

Also plan on a CB ($100-$200 installed).

For offroading, you will need to carry tools, recovery gear, first aid kit, fire extinguisher, and a cooler (lunch & drinks). For more extreme offroading, plan on carrying fluids and spare parts.

37” tires require re-gearing ($1500), upgraded driveshafts ($1,000+), upgraded front axle shafts ($700), and more clearance from either a body lift, flat fenders, or taller lift ($600-$1000s). 37” tires will eventually cause factory parts to fail. The factory warranty will not cover failures caused by non-factory parts.


Last edited by planman; 01-06-2009 at 11:38 PM..
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Unread 01-04-2009, 06:44 PM   #2
desertjk
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Looks like a lot of thought went into your description! Here are some somewhat random comments regarding my own buildup of a 2007 Rubicon with 35" tires.

I'm running 35's on my 2007 Rubicon 2 door and think it's a good all around tire size choice. I think they perform very well offroad and they seem to look proportional to the body (just a personal opinion).

I'm running a 3.5" RE lift, Procomp 8179 15"X8" wheels (I think these are 4.75" backspacing) and Goodyear 35X12.5 MTRs. I get a slight rubbing on the driver side rear tire with full stuff. Nothing else rubs. Probably a little less backspacing would solve it. There was more significant rub before I centered the rear axle as it was offset somewhat to the driver's side. Due to the geometry, it also tends to move laterally to the driver's side during compression.

I'm not much of a fan of body lifts. If you're doing it only for clearance, you might consider tube fenders or the Xenon flares as an alternative.

I'm running 4.88's with an automatic. I'm very happy with this combination (with the Rubicon 4:1 transfer case). On road this combination gives somewhat lower overall gearing (about 8.7% lower) than factory so the shift points, etc. are close to factory. Offroad, again, it's slightly lower than factory and with the 4:1 transfer case I think it's about right. I doubt that you'd really notice much difference between the 4.88's and the 5.13's so probably either is fine. My speedometer is off a bit but I just multiply - a programmer would be nice but, for the money, you could easily live without it. I would really not want to "get by" with standard gears and 35's, especially if you don't have the 4:1 transfer case gears.

I do not have any driveline clearance problems, even with the 3.5" lift. I am running the JE Reel 1350 style driveshafts and they may be a different diameter than stock shafts.

Regarding the strength of the stock sliders, I have bent the mounting brackets when lifting the Jeep with a hi-lift at the rear portion of the slider.

Personally, I'd opt for aftermarket wheels rather than spacers. I think there are a lot of varying opinions on this but I just feel like a spacer is a weak link at a place where you don't want one. The 15" Procomp 8179's that I'm running do not have any clearance issues with the calipers.

I've run both BF Goodrich MT KM's (lots of them) and the Goodyear MTRs. I'm sold on the MTRs. They're a lot quieter and are deemed to have stronger sidewalls. The Goodrich's always started out quiet but got very, very noisey and vibrated a lot as the miles grew, even with consistent tire rotations every 2 to 3 thousand miles. The MTR's seem to not have this problem, at least so far.
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2007 2 door Rubicon. 3.5" RE lift, 35" Goodyear MTRs, Procomp 8179 15x8 wheels, 4.88 Superior gears and alloy shafts. Shrockworks stubby front bumper, Rockhard rear bumper, JE Reel 1350 driveshafts, Warn Powerplant winch, CB, GPS.
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Unread 01-04-2009, 10:00 PM   #3
planman
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Sounds like you have a nice build. However, your budget for lift, tires, wheels, skids, gearing, driveshafts, etc., was much more than $2500. The lift, shocks, and driveshafts were probably pushing $3k alone. Wheels, tires, axle shafts, winch, bumpers, and gearing probably added another $6k+. Still, I really like your set up and agree with most all your observations.

My biases are different than yours on gearing--probably because of where I live--Montana. I prefer more power than economy and am not hesitant to run at higher rpms. With the mountain passes of Montana and Wyoming, 4.88 gears with 35s and an automatic would not be desireable with the 42RLE overdrive gear ratio of 0.69. Also, consider that the 3.8L JK mini-van engine is designed to run at higher rpms than the 4.0L strait 6 in older jeeps.

I think if you used the hi-lift at or between stock rocker guard mounting points, you would have not experienced a bend. I have used my stock rocker guards as sliders multiple times with no problems, but I can see that that much force was concentrated behind the mounting points, the leverage would cause bend. Although, I don't know if you would end up with body damage, rather a bent slider and mounting tab. My write-up suggests placing the priority on other expenditures first.

I also have a different bias towards minimal body lifts to gain clearance. I have been happy with my 1.25" BL on my 04 TJ. It is not very noticable, but makes it easier to clean my rig after wheeling, and it allowed me to add high clearance transfer case and gas tank skids. I have not used a BL on my JK, but for someone who wants to run 35s on a reduced budget, body lifts are a viable option. I chose to run Xenon flares rather than use a body lift to run 35s with a 2.5" suspension lift.

My bias is also different with wheel spacers. My TJ probably has had many trouble-free miles with Spidertrax wheel spacers. I re-torque the lugs on the spacers every time I rotate my tires (about every oil change), and I never had one came loose. I have only heard of a Spidertrax-quality wheel spacer failing when the internal lugs came loose. The failure was not in the spacer--rather in the maintenance by the owner.

However, my real bias on wheels is that I prefer steel wheels for wheeling and aluminum wheels for highway driving. Since I don't do much highway driving in my JK, I have run steel wheels with 4.5" or less backspacing since I brought it home.

Glad to hear your experience about MTRs. I am looking at going to 37x12.5R15 MTRs. I sold my 35x12.5R17s Toyo MTs last week. I want to move back to a C load rated tire on a 15" wheel, and plan to either do 35s in the KM2 or Toyo MT, or 37s in the MTR.

Finally, since you re-geared, a programmer is more personal preference than necessity. However, before I regeared to 5.13s with 35s on my 6 speed, the programmer made a significant performance and mpg difference when running stock Rubi gears and 35s. I definately would buy the programmer again--even if I was in your situation. Your build likely cost more than $9k--if you did all the labor--what is another $380?


Here is my build.



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Unread 01-04-2009, 11:34 PM   #4
desertjk
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Quote:
Originally Posted by planman View Post
Sounds like you have a nice build. However, your budget for lift, tires, wheels, skids, gearing, driveshafts, etc., was much more than $2500. The lift, shocks, and driveshafts were probably pushing $3k alone. Wheels, tires, axle shafts, winch, bumpers, and gearing probably added another $6k+. Still, I really like your set up and agree with most all your observations.

My biases are different than yours on gearing--probably because of where I live--Montana. I prefer more power than economy and am not hesitant to run at higher rpms. With the mountain passes of Montana and Wyoming, 4.88 gears with 35s and an automatic would not be desireable with the 42RLE overdrive gear ratio of 0.69. Also, consider that the 3.8L JK mini-van engine is designed to run at higher rpms than the 4.0L strait 6 in older jeeps.

I think if you used the hi-lift at or between stock rocker guard mounting points, you would have not experienced a bend. I have used my stock rocker guards as sliders multiple times with no problems, but I can see that that much force was concentrated behind the mounting points, the leverage would cause bend. Although, I don't know if you would end up with body damage, rather a bent slider and mounting tab. My write-up suggests placing the priority on other expenditures first.

I also have a different bias towards minimal body lifts to gain clearance. I have been happy with my 1.25" BL on my 04 TJ. It is not very noticable, but makes it easier to clean my rig after wheeling, and it allowed me to add high clearance transfer case and gas tank skids. I have not used a BL on my JK, but for someone who wants to run 35s on a reduced budget, body lifts are a viable option. I chose to run Xenon flares rather than use a body lift to run 35s with a 2.5" suspension lift.

My bias is also different with wheel spacers. My TJ probably has had many trouble-free miles with Spidertrax wheel spacers. I re-torque the lugs on the spacers every time I rotate my tires (about every oil change), and I never had one came loose. I have only heard of a Spidertrax-quality wheel spacer failing when the internal lugs came loose. The failure was not in the spacer--rather in the maintenance by the owner.

However, my real bias on wheels is that I prefer steel wheels for wheeling and aluminum wheels for highway driving. Since I don't do much highway driving in my JK, I have run steel wheels with 4.5" or less backspacing since I brought it home.

Glad to hear your experience about MTRs. I am looking at going to 37x12.5R15 MTRs. I sold my 35x12.5R17s Toyo MTs last week. I want to move back to a C load rated tire on a 15" wheel, and plan to either do 35s in the KM2 or Toyo MT, or 37s in the MTR.

Finally, since you re-geared, a programmer is more personal preference than necessity. However, before I regeared to 5.13s with 35s on my 6 speed, the programmer made a significant performance and mpg difference when running stock Rubi gears and 35s. I definately would buy the programmer again--even if I was in your situation. Your build likely cost more than $9k--if you did all the labor--what is another $380?


Here is my build.
Very nice Jeep!

I wasn't trying to disagree with any of your points, just adding in a bit of my own experience (and opinions) with 35s. I'm impressed with all the planning you did - I like to plan things out in great detail myself and always appreciate seeing others that take the time to do the same.
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2007 2 door Rubicon. 3.5" RE lift, 35" Goodyear MTRs, Procomp 8179 15x8 wheels, 4.88 Superior gears and alloy shafts. Shrockworks stubby front bumper, Rockhard rear bumper, JE Reel 1350 driveshafts, Warn Powerplant winch, CB, GPS.
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Unread 01-05-2009, 07:20 AM   #5
planman
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Thank you. I appreciate it.
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Unread 01-05-2009, 07:03 PM   #6
Racin444
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I just recently installed the Teraflex 2.5" BB lift kit and put some good year MTRs on 15s and I LOVE IT
The bumstops are amazing and the sway bar end links offered allows for the tires to tuck avoiding the pinch seam in the back. Teraflex is amazing!
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Unread 01-05-2009, 07:31 PM   #7
Bareass
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i was talking to my friend with a 4 door on 35s and a 4" lift and he says he rubs hard and has cut a groove into his tires. but it doesn't seem like the 2 door rub on 35s with the 2.5" or is it just that he may be running wider tires?
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Unread 01-06-2009, 07:45 AM   #8
planman
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Quote:
Originally Posted by Bareass View Post
i was talking to my friend with a 4 door on 35s and a 4" lift and he says he rubs hard and has cut a groove into his tires. but it doesn't seem like the 2 door rub on 35s with the 2.5" or is it just that he may be running wider tires?
If he is rubbing his rear tires, he needs to trim or fold over the pinch seam at the front end of his rear fender well. Or, his kit may not have included extended bumpstops--so he needs to buy some.

Here is a pic of a tire rubbing the rear pinch seam:



Here are pics of a guy who trimmed his pinch seam instead of using a BFH to fold it back:




I folded mine back. If your buddy trims his, he should consider either using JB Weld or something else to close it back up. He at least needs to paint over the bend or the cut to deter rust.
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Unread 01-06-2009, 09:04 AM   #9
mpo
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Quote:
Originally Posted by planman View Post
Is your jeep leaning at the rear? Not sure if my eyes are playing tricks on me since my friends' does that and we don't why and he's working on trying to level it out.
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Unread 01-06-2009, 09:50 AM   #10
planman
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No leaning. It is probably the angle and position of the camera.

Here is a pic on the same day from the other side.

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Unread 01-06-2009, 10:01 AM   #11
VegasJeep
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Quote:
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Is your jeep leaning at the rear? Not sure if my eyes are playing tricks on me since my friends' does that and we don't why and he's working on trying to level it out.
Im sure your buddies leans to the passenger side. It is the side with the fuel tank on it and even without the fuel in the tank it is an extra 100+ pounds that will cause a lean. Add a half a tank of fuel and your leaning even more
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Unread 01-06-2009, 10:07 AM   #12
mpo
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Im sure your buddies leans to the passenger side. It is the side with the fuel tank on it and even without the fuel in the tank it is an extra 100+ pounds that will cause a lean. Add a half a tank of fuel and your leaning even more
Nope, actually it leans at the rear and the front seems to be sitting higher.
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Unread 01-06-2009, 10:08 AM   #13
VegasJeep
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Nope, actually it leans at the rear and the front seems to be sitting higher.
is it stock? if not could be a HD spring for a winch bumper

If it is it could be that your looking at fenderwell opening... the rear will have less opening then the front.
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Unread 01-06-2009, 03:19 PM   #14
mpo
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Originally Posted by VegasJeep View Post
is it stock? if not could be a HD spring for a winch bumper

If it is it could be that your looking at fenderwell opening... the rear will have less opening then the front.
It has a 4" lift on it. I actually just looked up the lift he has on his Jeep and he's got the one under "JK Suspension Systems" on this site: http://www.4wd.com/jeep/explorer-pro...uspension.aspx

Quote:
This 4" front / 2" rear suspension system installs quickly and easily. Specifically rated 4" front springs are used to reduce body roll and brake dive. Rear 2" coil spacers are used maintain factory ride characteristics, load capacity and proper lateral stance.
Does that sound like a good kit he's got or is something not right about that?

Last edited by mpo; 01-06-2009 at 04:10 PM..
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Unread 11-25-2011, 08:33 PM   #15
dennypoo
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What do you think of AEV's Nth Degree DualSport 3.5 in? It seems to come with just about everything you'd need other than the tires...
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