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Discussion Starter · #1 ·
There are several lift kits on the market for a standard lift as well as the AEV kit for a bigger lift. I have the Rusty's system on my XK and thought I'd give some feedback for anyone was interested.

I've noticed at least one kit being used that uses poly spacers for the front strut. The Rusty's uses a precision laser cut steel spacer for the front strut along w/ the poly spacer for the rear. The Jeep tech that installed this kit on my XK is a suspension lift specialist at my dealership w/ tons of experience. He has preference for this kit on a standard lift w/ the exception he replaces the Rusty's shock w/ a different Jeep shock that has more travel and he replaces a few other small parts not included w/ the kit.

I have the factory Hulk wheels which I like and will retain. I will opt for a tire at least one and possibly two sizes over the factory Forteras. I'm looking at the new Wrangler SAs but will wait to see if they get positive feedback first. For the two sizes up the tech adds a particular spacer for the factory wheels, removes the wheeltubs to modify the steel understructure, then modifies and replaces the tubs. He also recalibrates the computer for the taller tires.

For now w/ the factory sized Forteras I took some basic measurements to give those who are interested an idea where they would be. The lowest point is the rear diff (of course) which can only be raised w/ a taller tire. The factory specs are 8.6" clearance (IIRC) but for whatever reason mine measures 9" @ 35psi. My front skid clearance is 11 1/2", front body panel (w/ air dam removed) is 15", rear body panel is 21", and bottom of side rocker panel is 14 1/2". The differential breather tube was modified and it should be good for about 2 feet of water as is. When I change tires I should be good for another 1-2" on all measurements. I would like to add a rock ring to the rear diff and I'm looking at the 4XGuard's upcoming rocker skid system as well.

As far as the Rusty's goes, the ride feels about the same as stock just higher. The lift appears to level out the XK more so than the factory nose down lean. As a result, I think my fuel economy may have dropped a tad (probably due to air flow). I haven't taken exact measurements of the improved approach/departure/breakover angles but all have obviously improved.

I am pleased w/ this setup and I think it is worthwhile w/ factory sized tires up to about two sizes larger. Beyond this, I would look at the more radical AEV lift.

XKPearl:)
 

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XK, I am running the Wrangler SilentArmor tires on my Cherokee and love them. The dealership is swaping out my Forteras for the Wrangler SilentArmors on my Commander as soon as it arrives at the dealership in a week or two.
 

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Discussion Starter · #3 ·
rubicontrail.net said:
XK, I am running the Wrangler SilentArmor tires on my Cherokee and love them. The dealership is swaping out my Forteras for the Wrangler SilentArmors on my Commander as soon as it arrives at the dealership in a week or two.
That's good to hear. Give some feedback on the SAs when you get the Commander.

Thanks,
XKPearl:)
 

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I am interested in your comment that the Jeep tech "also recalibrates the computer for the taller tires". I would like to know more about this. Is there a way for us meer mortals to do this?
 

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XKPearl said:
That's good to hear. Give some feedback on the SAs when you get the Commander.

Thanks,
XKPearl:)
If my Commander ever arrives. It has been sitting completed in Michigan for over a week. :( I wish they would hurry up and put it on a train on it's way out here.
 

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Discussion Starter · #6 ·
I'm unsure if aftermarket computer chip tuners are available for the XK. Those that come out are generally basic and you would be very limited to what you can change. The dealer can change a whole host of things. I think the most basic is to ensure that you recalibrate for the taller tire so the speed sensor is not off. You may need to change your TPMS thresholds if the bigger tires run a different pressure range, etc.

XKPearl
 

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Discussion Starter · #7 ·
I'm now leaning towards the Firestone Destination M/Ts:

http://www.4x4review.com/products/tires/Firestone-Destination-MT.asp

265/70s on the "Hulk" rims should work well. I can mount a larger spare on the roof, but has anyone run into problems w/ a 32"x10.5" in the factory spare mount (especially w/ a hitch)?? Rough measurements appear that I'd need to remove material from the front of the hitch receiver.

Also, I'll considering adding an ARB rear locker when they come out.

XKPearl
 

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Discussion Starter · #9 ·
As far as the Rusty's installed by my dealer is concerned, everything works correctly. I would assume that the RR kit works the same provided the speed readings were corrected for the taller tires. To the best of my knowledge the AEV system does not work because of the change in geometry. It is also my understanding that they are working on a software correction for this but it is not out yet.

XKPearl
 

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I'm also interested in how you recalibrated for larger tires - I know the dealer can only program tires that are available from the factory which is only 245/65R17 on our Commanders.

I have no issues with 1" of lift and 245/75R17 tires.
 

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Discussion Starter · #11 ·
That does not sound correct. My dealer has calibrated for several different sized tires at least two sizes up on the XK, three sizes up on the WK and huge mudders on the TJ. They go by revolutions per mile.

To the best of my knowledge, the Rusty's and the RR maximizes the amount of lift available w/ the stock geometry without much change if any w/ the handling characteristics. Once it is properly calibrated to the correct speed (if you change the revolutions per mile w/ your tires) then all of the electronic features will work no different than stock. I would assume that if they figure out a software correction for the more radical AEV lift, then that would work as well.

XKPearl
 

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TJ yes, WK/XK no - I have watched them try. Find out what tool your dealer is using because if he's doing it he's the first I've heard of. Thanks for helping the rest of us out!

Is it possible he's telling you something he didn't do?
 

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Discussion Starter · #13 ·
I'll see him tomorrow and will ask. And he himself has a WK w/ 285s that is recalibrated and they just finished another XK w/ 265s that is recalibrated. When I pick my tires out they will recalibrate mine. They would not be able to sell these as new cars under warranty if they couldn't recalibrate the electronics to register the correct speed and odometer readings and the electronics were askew.

XKPearl
 

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Discussion Starter · #14 ·
Just out of curiosity I did a quick check w/ AEV and copied this:

"The suspension will be somewhere in the $1500 to $1700 range which includes reflashing the computer. A computer reflash is required because of the new tire size (speedometer calibration) and ESP (Electronic Stability Program). The flash would also be required for DHS (Dynamic Handling System) equipped vehicles, but AEV will not be using the DHS option on the Mojave edition due to the fact that WK's equipped with this feature have less wheel travel."

This sounds exactly like what my service guy told me and they've been doing this since 2005 w/ the WKs which has the same transfer case/trans as the XK. I'll ask for details tomorrow, but I can see no way that Jeep will produce any vehicle that you cannot calibrate the speedometer/odometer. What were these Jeep techs actually doing when you watched them try to recalibrate the speedometer?

XKPearl
 

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Discussion Starter · #15 ·
JeepCollector said:
TJ yes, WK/XK no - I have watched them try. Find out what tool your dealer is using because if he's doing it he's the first I've heard of. Thanks for helping the rest of us out!

Is it possible he's telling you something he didn't do?
I met and spoke w/ him this morning:

They use a Windows based Star Scan Tool which is used on all 2005 and up CAN BUS vehicles such as WK, XK, 300s, Compass, etc. You plug the unit into the computer and go to set up options where you can customize the settings for tire aspect ratio and gearing.

He said that if the Jeep service department you went to neither had this tool nor knew how to use it, that they had no business lifting and/or modifying the Jeep or 300 for that matter. He further said that he could'nt see how Jeep would authorize a dealership to sell such modified vehicles w/out reflashing the computer because the speed, odometer, and electronics would be out of spec. He suggested you find a dealership that knows how to work on the WK/XK or go to a place such as AEV to get your modifications checked out and corrected if needed.

Hope this helps,
XKPearl
 

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This is great info Pearl.

I have to get my XK calibrated for the RR lift kit.

Thanks!
 

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I am familiar with the Starscan tool - on CAN vehicles it does offer the option to reprogram for tires and gears, but only to the factory available sizes and ratios.

Don't get your hopes up fellas - it's not very likely.
 

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Discussion Starter · #19 · (Edited)
I'm not sure I follow you. What I saw was a tool (StarSCAN) that communicates w/ the onboard electronic control units. It's a flash file that is downloaded and used by this tool to reflash the computer not the tool itself alone (Is this not correct?). Are you saying that the flash files that AEV and this particular tech is speaking of does not exist? If so, what is your basis for this claim?

I know that AEV modifies and sells factory new WKs and now XKs. The tires and gearing on these vehicles are anything but stock. AEV claims that flash files exist to reflash the computer for these modifications. On the same note, the person I deal w/ says the same thing as AEV and they also sell factory new WKs and XKs that have tires other than 245/65R17s. If you're claiming they are snowing me over, arm me w/ some facts (ammunition) so I can take it to AEV and my guy. I wanted to share this information to help others but I'd also like to know if someone is lying to me.

Thanks,
XKPearl
 

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AEV (and maybe even your dealer) is not using standard Starscan software available to every dealer. If they have a way to modify for tire size it is different software that either someone has cracked or has pirated. If somebody is offering that to dealers, then problem solved. But as far as I know, most dealers cannot adjust for tire sizes. Heck, there's not even a speedometer correction box by TruSpeed or anyone else for CAN BUS vehicles.

Let us know how the rest of our dealers can get this software if that's the case. Thanks! :)
 
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