While I'm at it.........
(As copied from Jeepforum.com)
WJ Suspension Info Thread
- Disclaimer: Most of the info in this thread is first hand however some I gathered from this forum. People have different experiences so what works for me may not work for you and vice-versa.
- A lot of this information can also be applied to the ZJ. Changing a hub or axle shaft is the same on either model for example.
Well since I feel like it I am going to try and maintain a thread of info pertaining to WJ suspension information - and maybe later I'll add some drivetrain specific information.
Control Arm lenghts:
(Measured from center of eye to eye)
Stock Front UCA: 15"
Stock Front LCA: 15 3/4"
At 4.5-5" I have the following measurements on my front CA's and don't have any DW - very very minor bump steer so this is a good place to start off from (I have RE front & Teraflex rear control arms):
RE Front UCA: 16"
RE Front LCA: 17"
Teraflex Rear LCA: 18.5"
LCA Bolts: 21mm (Both nut and bolt)
UCA (Axle side) 17mm ***
UCA bolt (Frame side) 13mm
UCA nut (Frame side) 15mm (Don't need to hold this nut since it has an anti-spin washer on it)
*** This is the size of the metric grade 10.9 bolt that Kevin ships with his lift kit. The stock bolt is a T50 I believe, possibly T55
Even though all of the bolts on my front suspension were already metric grade 10.9 (which is slightly weaker then SAE grade 8 bolts) I decided to upgrade to Grade 8. They are slightly bigger diameter and stronger + cheaper.
Upgraded UCA axle bolts to: 2.5" x 7/16"
Upgraded UCA frame bolts to: 2" x 7/16"
Upgraded LCA axle & frame bolts to: 4 1/2" x 9/16"
I then added appropiatly sized washers to both sides.
Torque specifications from 04 WJ FSM:
LCA Frame: 115 ft/lbs
LCA Axle: 120 ft/lbs
UCA Frame & Axle: 45 ft/lbs
Trackbar Frame & Axle: 74 ft/lbs
Front shocks upper nut: 26 ft/lbs
Front shocks lower nut: 250 in/lbs (21 ft/lbs
Hub bearing knuckle bolts (the 3 12 pt 13mm bolts holding the hub bearing assembly to the knuckle): 75 ft/lbs
Main hub nut: 175 ft/lbs
Lower Ball Joint: 80 ft/lbs
Top Ball Joint: 75 ft/lbs
Rear shocks upper bolt: 80 ft/lbs
Rear shocks lower bolt: 85 ft/lbs
Upper A-arm Ball Joint nut: 105 ft/lbs (enjoy getting a torque wrench up there!)
Upper A-arm frame bolts: 74 ft/lbs
Ball joint plate bolts (3 of them): 100 ft/lbs
LCA Axle side bolt: 120 ft/lbs
LCA Frame side bolt: 115 ft/lbs
Pitman Arm Shaft Nut: 185 ft/lbs
Drag Link Pitman Arm Nut: 65 ft/lbs
Drag Link Knuckle Nut: 35 ft/lbs
Drag Link Clamp Nut: 30 ft/lbs
Tie Rod Knuckle Nut: 35 ft/lbs
Tie Rod Clamp Nut: 30 ft/lbs
Steering Damper Axle Bolt: 65 ft/lbs
Steering Damper Tierod Nut: 30 ft/lbs
That is based off of stock hardware so if you upgrade to grade 8 you can probably get away with some added torque on them - especially if you have some clunks from them. This is what happens if you torque down grade 8 hardware too much
Note on torquing down suspension components:
Always torque down anything with bushings when the hardware is at its normal position. For control arms that means don't torque them down until you have your Jeep back on its wheels sitting on the ground @ ride height. This is VITAL to ensure the integrity of your bushings. This is what happens if you torque it down without any weight on the control arms after 3-4 months of use.
Short guide on HOW TO replace the front wheel bearing hub assembly or a front axle shaft:
Speciality parts needed:
- 36mm socket
- 12 pt 13mm socket
- Big breaker bar
- Metal coat hander or big zip ties
Step-by-step w/pics on how to replace an axle/hub assembly
- Jack up and remove wheel.
- Remove cotter pin, retaining washer + spring from hub.
- Have someone apply the brake while using the 36mm socket + breaker bar to remove the big arse nut
- Either remove the caliper or the caliper bracket from the knuckle and using the zip ties or a metal coat hanger, hang the caliper from the spring - don't let it rest from the brake line.
- Using the 12pt 13mm socket remove the three hub to knuckle bolts from the backside of the knuckle.
- The hub will now pull off - at this point you can also replace the axle shaft as well or the hub bearing assembly.
- Reverse steps 1-5
Sometimes removing TRE's (Tie Rod Ends) from tapered holes is easy, and sometimes you'll curse the man who invented tapered holes. The easiest solution is to use heat. I banged away at this one for hours
until I applied heat and after 2 minutes of heat
it practically fell off after I destroyed the head of this puller
. A little burning never hurt anyone
Kevins/Kolak's 2.5" lift consists of:
- 2.5" Polyurethane spacers
- Optional shocks
An all too commonly asked question is whether you need
to get new shocks. Short answer: no, you don't need
them. But you'll certainly WANT
them very quickly. The shocks will wear out quickly and going over bumps they will max out and make the ride very poor. I ran RE (Rubicon Express) Twin Tube shocks and they are stiff, no getting around that. The Mono Tubes are better and are worth the upgrade if you plan on sticking with the BB for a while. Bilstein & MX6 shocks are the "pimp" shocks of choice
Another frequently asked question is at which point do you need a new trackbar. Lets start off with this: Getting a non-adjustable trackbar is a bad move
. I ran Kevins 2.5" poly lift with the stock trackbar and didn't have any issues. It is called a BB (Budget Boost) for a reason. It is cheap. My personal believe is that once you pass the BB stage, suck it up and realize you'll need to commit some money to your Jeep and buy an Adjustable JKS Trackbar
. JKS makes them for both the ZJ and WJ. A really good conversion for your ZJ is Kevins "Trackbar Conversion Kit" which runs a WJ style trackbar and a beefed up TB bracket. So once you hit 3", buy an adjustable trackbar. I like JKS, there are other brands out there though. People most certainly do run 3" lift with the stock trackbar, but I think you're just delaying the inevitable like that.
Transfer Case Drop Kits!
Don't waste your money on these. If a kit you buy has one, see if you can get it removed from the kit and if you can't, just don't install it. If you lift your Jeep 4", and install a 1" drop, you have only lifted the lowest part of your Jeep 3". You might as well have just lifted your Jeep 3" and not installed the TC drop at all. I am at 4.5" and don't need one. Generally people around 5.5" or higher start to need them, but not always.
Lots of people make them, Procomp, OME, Rusty, Skyjacker, Monroe, etc... Find what works for you. Kolak prefers the Monroe SS. I like the OME SS. The bigger the tire you put on, the faster you'll go through the SS. If you take the stock SS and compare it to an OME SS, you'll wonder why Jeep ever installed a SS in the first place. I was at 4" of lift, running 31" tires on the stock SS and it was just fine. I didn't replace it until I hit mine on a rock. Others may find they need one running a 2" lift with 31" tires. Each Jeep is different. It certainly doesn't hurt to install one sooner then later, but it can suck driving around with DW because your SS is undersized or worn out. I go through SS's more frequently then I care to admit (About every 4 months) but I beat on my Jeep pretty hard at the same time
3" Lift components:
Personally, I would get this at a minimum for 3" of lift:
- Adjustable front trackbar (and rear if you're on a ZJ although less necessary)
- Decent Shocks
- JKS Quicker Disconnects
- Springs of course (or a BB & UC I suppose...)
You'll be able to get away with using the stock rear sway bar end links...
Kevins/Kolak's 4.5" lift consists of:
HIGHLY suggested items:
- RE (Rubicon Express) front adjustable UCA (Upper Control Arms) & LCA (Lower Control Arms)
- Teraflex rear adjustable LCA's
- Teraflex rear extended sway bar end links
- Teraflex rear aluminum A-arm spacer
- Teraflex 4" springs (net 4-5" of lift)
- JKS Adjustable Trackbar
- Your choice of shocks - I have MX6 shocks and love them
Luxury suggested items:
- JKS Quick Disconnects
- JKS Super Nerfs
- JKS Tie Rod
- Bump Stop Extensions (See post #5 on my updated thought on bump stop extensions)
- OME HD SS (Old Man Emu Heavy Duty Steering Stabelizer)
- Tom Woods front Double Cardan (@ the Transfer Case) / U-joint (At the pinion) drive shaft with the standard 3" of slip travel.
Arlo's thoughts on sliders:
- JKS Drag Link (HIGHLY suggested for big tire sizes)
- JKS BPE (Bar Pin Eliminators)
A lot of people recommend Kevins LP-2 (or LP-1) Rocker Guards (Sliders) - in fact that is what I have - but compared to the JKS Super Nerfs they don't stick out as far (about 1.5" less) so if you're looking for true lateral protection (ie for rocks) stick woth JKS Super Nerfs (Available through Kevins website (www.kevinsffroad.com
), Nick (firstname.lastname@example.org
) or directly from the JKS website (www.jksmfg.com
Arlo's thoughts on mileage:
This is specific to my setup which is the 4.0L with 3.54 gearing running @ 5300ft or higher in elevation.
****The higher I went and the bigger tire I put on my Jeep the less in a hurry I was. I drove slower, accelerated slower, and as a result didn't hurt my mileage as bad as if I had kept a heavy foot as I did when stock. Elevation played a role in this - being so high up means I have less power so typically someone at sea level will get better mileage since their engine doesn't have to work as hard.
Arlo's thoughts on wheels:
- When 100% stock I got ~14 in the city and 20 on the highway.
- When running a 2.5" BB, 31" AT's, and the stock aluminum wheels I got ~13.5-14 in the city & ~18 on the highway
- When running a 5" lift, 31" AT's, and the stock aluminum wheels I got ~ 13.5-14 in the city & ~16 on the highway ****
- When running a 5" lift, 32" MT/R's, and 16x7" steelies (Crager Soft 8's) I got about 12.5-13 in the city & ~14-16 on the highway (highway = 65-75mph and most likely in the mountains)
The stock wheels on WJ's are either a 16x7" or 17x7" wheel with 6" of BS (Backspacing). If you want go move down to a 15" wheel (because both tires and wheels are cheaper + you'll get a better seal betwen the tire and wheel) then the only way you'll get it to clear the caliper is to get a STEEL wheel with ~4" of backspacing. The steel means the wheel will be thinner and thus make the inner radius larger and the decreased backspacing will push out the wheel further away from the caliper.
Arlo's thoughts on the width of wheels:
A narrower wheel will ensure a better seal between the tire and wheel when you airdown offroad. However if you have too wide of a tire and too narrow of a wheel it is bad (mmm, kay). This is just my opinion but when you have anything under a 11" wide tire stock with a 7" wide rim. As soon as you hit 11.5" wide or more, jump up to an 8" rim. If you visit the various tire manufaturer websites you'll see that for each tire they recommend a minimum wheel width which for the most part should be followed.
I run a 16x7" steel (Crager Soft
rim on 265/75-16 (10.4" wide) tire and I airdown to 12-14psi. I have never completely popped a bead but I have had air hissing out from a rock poking in. A narrower wheel also helps protect it from rock rash as well as protects the valve stem.
Arlo's thoughts on tires:
- I ran 31" AT's (245/75-16 Big-O BigFoot AT's) w/o any lift and rubbed on the plastic wheel well lining when backing up and my wheels turned.
- Running 245/75-16's with a more aggressive tire (like an MT) will result in more meaningful tire rub
- Running a 31" tire w/o a lift and disconnecting your swaybar will mean a lot more rubbing then if you leave the swaybar connected.
- When I moved up to a 2.5" BB from KOR (Kevins Offroad) and kept my 245/75-16 AT's I didn't have any rubbing. This is a good size tire for this lift. An alternative is an 265/70-16 - slightly wider tire.
- When I moved up to 5" of lift and 32" MT/R's (265/75-16) I had to trim about 2" from both my front bumper cover (the plastic) and the bumper itself (the metal hid behind the plastic wheel lining which was also removed).
If you don't plan on trimming much:
- Less then a 3.5" lift and stick with 31's.
- 3.5" or more, 32" tires.
- 5" or more, 33" tires.
I won't suggest any other tire size. Can you fit 32" tire on a BB? I don't care - I don't recommend it
. That doesn't mean you can't do it. It is your Jeep, remember that! Screw what other people think - this is just a guide.
How to calculate between metric tire sizes (xxx/yy-zz) to SAE sizes (AA x YY"):
We'll use a "32 inch" tire for an example. I quote it because SAE and metric sizes don't match up perfectly.
Arlo's thoughts on WJ brakes:
- 265/75-16 is what you'll see on 16" rims
- 32x10.5" is what you'll see on 15" rims
- 265 is the width of the tire in mm (millimeters), 75 is the aspect ratio between the width of the tire to the height of the tire, and 16 is the size of the rim the tire fits on.
- The goal is to calculate the height of the sidewall of the tire and then add the size of the wheel to it.
- Take 265 and convert to inches by dividing by 25.4 (265/25.4 = 10.4" wide)
- Now using the aspect ratio (.75) determine the size of the sidewall by multiplying the 10.4 by .75 to get 7.8". That is the distance between the edge of the rim and the outer edge of the tire. Double this because you have two - 15.6"
- Now take the 15.6" (the height of the sidewalls) and add 16" (the size of the tire) to get 31.6" - the size of the tire making a 265/75-16 a 31.6"x10.4" tire - which as you can see is slightly smaller then the SAE counterpart of 32x10.5"
Throughout the production of the WJ there were two different brake calipers offered. The first was in production between '99 to the middle of the '02 model year. Their weakness was applying unequal force to the rotor and thus causing it to warp/wear unevenly. In mid '02 Jeep switched to Akebono calipers to "fix" the problem. For some it fixed the problem, others still ran into warped rotor issues.
Warped rotors are diagnosed by anything from mild to heavy braking causing a pulsing or vibrating feeling in the peddle & steering wheel. The worse they get the less hard you'll have to brake to feel the warpedness (I have a copyright on that word so back off).
This link shows the new calipers on the left and the old on the right.
Some people use the old style calipers and never have warped rotor issues. Others (myself included) can warp the new style quite easily. My rotors would last for only ~9 months before they were warped. I have heard the new style calipers run between $150-$350 so upgrade at your leasure if you have the old style. However since that may not fix your problem switching to a one piece rotor may be your real salvation. The Brembo rotors that I run have been great for the past 18 months I have had them - most of which time I have been running bigger then stock tires so I have been working them harder. Basically any one-piece rotor will solve the warping issue. The stock two-piece design (two pieces of metal connected vs a solid piece in the first place) is one of the reasons thought to be the reason for warping.
The new style (Akebone) are slightly larger then the original size so if you have aftermarket wheels on there check for clearence. I picked up my Brembo Rotors from www.tirerack.com
Arlo's thoughts on the speedometer with bigger tires
When I changed from stock (235/75-16) to my AT's (245/75-16) I found my speedometer to be nearly dead on. That means that when 100% stock my Jeep said I was going faster then I actually was. So when I moved to AT's there was no reason to adjust my speedometer. However when I toss on my MT/R's (265/75-16) I am about 5-6% slow - meaning when my speedometer says 75 mph, I am going 78-79ish.
WJ's are unique (bad thing) in that they don't measure the speed from the transfer case output shaft like the ZJ's do, we measure it from the tone rings on the rear axle. This means that we can't change a gear in the TC to compensate for different size tires like a ZJ can, we have to go the electronic programming route - or just be smarter then the speedometer and know to drive a little slower. For those that thinking changing the gearing in the diffs would help, it won't - since the speed is based off of the post-diff wheel speed. A TrueSpeed Calibrator (Thanks walter_da_jpr), $190ish, is a programmer that can adjust the speedometer to be accurate for larger tire sizes. Anything over 32 and it'll be pretty far off and probably worth the money to adjust your speedometer.
There seems to be some variations between years so it is best to verify this yourself. I measured all of the speeds via GPS.
If you plan on swapping out your rear axle for one w/o tone rings (ie upgrade to an 8.8, 9", D60 etc...) then you'll lose your speedometer and ABS. A way to keep your speedometer is to rewire your rear ABS sensors into your front wheel sensors - that way you'll be measuring your speed off of those wheels.
ANOTHER alternative is to swap your TC for one that has a speedo sensor on the output shaft. And then you'll have to do some investigating - you'll need a ECU (I believe) from a Dodge Dakota, to convert the T-case speed signal into a signal that the computer on the WJ can use. A lot of work and I believe JohnBoulderCO from www.mallcrawlin.com
has a writeup on how he did it.
Useful links:Suspension & Steering Geometry
Function of all those black bars up front:
Drop Pitman Arm & Trackbar Brackets:
- Coming out of the Steering Box is a shaft
- Connected to the shaft is the Pitman Arm
- Connected to the Pitman Arm is a ~3 ft long rod called the Drag Link
- The Drag link had DLE (Drag Link Ends aka TRE's) on either side.
- The DLE on the lower side connects to the passanger steering knuckle.
- From the passanger steering knuckle a ~5ft rod contains TRE's (Tie Rod Ends) on either end and connects the drivers & passanagers steering knuckles together.
- The Tie Rods functions is to keep both wheels parallel to each other.
- The trackbar controls the lateral (side-->side) movement of the axle relative to the "frame". It connects to the frame on the drivers side and to the axle on the passangers side.
- Some lift kits come with a drop pitman arm OR a drop trackbar bracket. THEY NEED TO BE INSTALLED IN PAIRS!
- Most WJ's never need one. The trouble with them is that the trackbar is so important on a WJ that if it isn't really beefy it allows side-->side movement and can cause deathwobble really easily.
- The drag link and trackbar MUST stay parallel to each other. That is why you can't just install the drop pitman arm or the trackbar bracket. If you install just one, they are no longer parallel.