Econolift Questions

GlowingBulb · **Posted:** Tue Dec 02, 2014 6:32 am

I think I'm going to bite the bullet in the next few weeks & buy an Econolift kit to reduce the scraping as I follow the Land Rover Defender tracks around the estate that I shoot on. I'm pretty sure that even with an extra 3.5" of clearance my Cherokee CRD (Liberty) will still be lower than a Defender but we all know that every inch helps :wink:

Lifting the Cherokee shouldn't be too difficult but selecting the right tyre is turning into a real PITA. Currently I've got 255 55 18's AT2's (29") which were on the Jeep when I bought it, ideally I'd like to keep the rim & just replace the rubber but there doesn't seem to be many options to increase the OD of the wheel to around 31".

I've checked JBA's tyre size chart which seems to be for the KJ - is this still applicable for the KK? I get lost reading on here about offsets etc so I'd really appreciate somebody answering the following questions:

Is there a tyre size out there that would work with my current rims & a 3.5" lift?

If I have to buy new rims would these have the correct offset? - https://www.4x4tyres.co.uk/cherokee-lib ... -6332.html

Finally if the rims above are OK would Discoverer STT 265 75 16 tyres work or would they rub like hell?

Thanks in advance guys! :lol:

tommudd · **Posted:** Tue Dec 02, 2014 8:38 am

GlowingBulb wrote:

I think I'm going to bite the bullet in the next few weeks & buy an Econolift kit to reduce the scraping as I follow the Land Rover Defender tracks around the estate that I shoot on. I'm pretty sure that even with an extra 3.5" of clearance my Cherokee CRD (Liberty) will still be lower than a Defender but we all know that every inch helps :wink:

Lifting the Cherokee shouldn't be too difficult but selecting the right tyre is turning into a real PITA. Currently I've got 255 55 18's AT2's (29") which were on the Jeep when I bought it, ideally I'd like to keep the rim & just replace the rubber but there doesn't seem to be many options to increase the OD of the wheel to around 31".

I've checked JBA's tyre size chart which seems to be for the KJ - is this still applicable for the KK? I get lost reading on here about offsets etc so I'd really appreciate somebody answering the following questions:

Is there a tyre size out there that would work with my current rims & a 3.5" lift?

If I have to buy new rims would these have the correct offset? - https://www.4x4tyres.co.uk/cherokee-lib ... -6332.html

Finally if the rims above are OK would Discoverer STT 265 75 16 tyres work or would they rub like hell?

Thanks in advance guys! :lol:

Be better to stick with a 245-75-16 or 265-70-16 both about the same height
265-75-16 is pushing it with not only height but also need to regear
16X7 with 4 inches of backspacing works best , no need for a 8 inch wide wheel since we can not run a tire needing a wheel that wide. With 7 inch better to air down etc

GlowingBulb · **Posted:** Tue Dec 02, 2014 8:44 am

Thanks for the info Tom!

Out of curiosity, what drives the requirement to re-gear; I assume a loss in torque & obviously the speedo reading the wrong MPH. Is there also an increased risk of damaging something in the drivetrain?

huntb · **Posted:** Tue Dec 02, 2014 9:04 am

GlowingBulb wrote:

Thanks for the info Tom!

Out of curiosity, what drives the requirement to re-gear; I assume a loss in torque & obviously the speedo reading the wrong MPH. Is there also an increased risk of damaging something in the drivetrain?

Whenever you put larger tires on you run the risk of damaging something in the drivetrain with the new rotational inertia created by the larger diameter tire, but if you go with 31's or 32's that probably isn't going to do too much harm. Tom (and many others) recommend regearing with larger tires to get the performance back from an already sluggish KK. I run 31's on my KK and so far have not felt the need to regear, but if I had the money I definitely would

tommudd · **Posted:** Tue Dec 02, 2014 10:04 am

GlowingBulb wrote:

Thanks for the info Tom!

Out of curiosity, what drives the requirement to re-gear; I assume a loss in torque & obviously the speedo reading the wrong MPH. Is there also an increased risk of damaging something in the drivetrain?

Engines are built to operate best in one operating range ." For example" at highway speed you might of been turning 2100 RPM when stock, with today's computers etc that's where it operates most efficiently. Now install larger tires and you have dropped that rpm down to maybe 1600 RPMs, its now sluggish, the transmission is searching for the right gear so will be going back and forth causing more wear and higher trans temps. Its a Catch 22 when you lift and install larger tires. Change one thing and it affects 10 other things
Mine went from 20-21 down to 15 MPGs when I went from 265-70-16s to 265-75-16s couldn't use overdrive anymore, hated it the two weeks I drove it until I re-geared
Now back to 21 plus, no down shifting all the time runs almost like it did stock

Bmxer524 · **Posted:** Tue Dec 02, 2014 6:37 pm

I think that offset would be too much. +20 would push the rim in quite a bit. Generally once lifted most stick to about 0 offset. Offset is a different way of measuring how a rim would sit. It measures the same thing as backspacing.

4" of backspacing on a 7" wide rim is 0 offset, 4.5" of backspacing on an 8" wide rim is 0 offset.

16" rims are more preferable for wheeling. More rubber means more cushion and less worries about damaging the rim especially after airing down. Stick to 245/75-16 or around that height unless you want to regear. So 31" or under.

265/75-16s are 32s. You'll need to regear to either 4.10s or 4.56s to keep power and mileage. Also they will be tight at 3.5". With that said, you can pound the pinch welds and possibly do a bit of massaging to the wheel liners to run them(don't hold me to this though...). That's my future plans. I want to run 32s on about 3.5-3.75" of lift.

Scar0 · **Posted:** Wed Dec 03, 2014 2:36 pm

One thing folks are missing here is the CRD has a different power band then the 3.7 does.
Depending on the type of trany behind the 2.8 the gear ratio is also different.

GlowingBulb · **Posted:** Wed Dec 03, 2014 4:42 pm

Thanks for the replies guys, I've got the CRD version which has quite a wide torque band so I'm guessing the performance hit wouldn't be too bad.

I'd not even thought about the hit to my already poor MPG (24ish) so thanks for that Tom, certainly food for thought!

I'll have to do some more reading about offset & backspacing... I understand offset well enough I think (the position of the outer rim in relation to the hub / outer arch?) but backspacing... :?:

lfhoward · **Posted:** Wed Dec 03, 2014 4:44 pm

I wish they sold the CRD here in the US! I got 17.2 mpg on a road trip on US-12 today.

I saw 17.8 at one point, until some towns got in my way. :JEEPIN:

17.5 is about the best I get with my Duatracs and roof basket unless I'm driving behind a semi on the Interstate. In that case I sometimes average 19.5 mpg.

tommudd · **Posted:** Wed Dec 03, 2014 4:54 pm

Scar0 wrote:

One thing folks are missing here is the CRD has a different power band then the 3.7 does.
Depending on the type of trany behind the 2.8 the gear ratio is also different.

True but no matter if CRD or gasser it still affects the power and mileage a lot
doesn't matter there is a different power band it still has one that the engine operates best in
Its been proven before that regearing a CRD helps a ton on both

Bmxer524 · **Posted:** Wed Dec 03, 2014 7:46 pm

GlowingBulb wrote:

Thanks for the replies guys, I've got the CRD version which has quite a wide torque band so I'm guessing the performance hit wouldn't be too bad.

I'd not even thought about the hit to my already poor MPG (24ish) so thanks for that Tom, certainly food for thought!

I'll have to do some more reading about offset & backspacing... I understand offset well enough I think (the position of the outer rim in relation to the hub / outer arch?) but backspacing... :?:

Backspacing and offset are different ways to measure the same thing. To measure backspacing you lay a rim face down, put a yardstick across, then measure from the mounting surface to the yardstick. Offset is how far off it is from the center of the rim.

This should help explain it:

Oh and I've never seen that kind of mileage with my gas KK. The best I saw was 22mpg pure interstate when I was stock. Now that I'm lifted and run bigger tires the best I saw was about 18mpg.

oktane17 · **Joined:** Thu Oct 14, 2010 4:22 pm **Posts:** 54

HUNTB; I am loving how your KK Sits. Im doing the OME HD springs, top plate lift as well. Adding A-arms in the spring. Will that give me the same stance as yours? Only difference I think is the Ironman shocks. Im using OME.

Bmxer524 · **Posted:** Thu Dec 04, 2014 12:10 am

oktane17 wrote:

HUNTB; I am loving how your KK Sits. Im doing the OME HD springs, top plate lift as well. Adding A-arms in the spring. Will that give me the same stance as yours? Only difference I think is the Ironman shocks. Im using OME.

I think he added to it recently, I don't know for sure. I'm sure he'll say what he's running. But yes, if you put the same springs and spacers that he runs you'll sit at his height(give or take a little to account for sliders, skids, etc). The only other way to get his "stance" is if you go with rims with the same specs to his. So same width rim with the same amount of backspacing. A-arms don't effect stance, they just help with clearance and alignment when lifted. Shocks will just effect travel and ride.

oktane17 · **Joined:** Thu Oct 14, 2010 4:22 pm **Posts:** 54

Thanks Bmxer! Im getting all my goodies together (OME Lift, ATH Bumper, Hella 700 FF's and Tires, D rings and some other stuff ready) Doing it all in one shot on a weekend in a few weeks.

Bmxer524 · **Posted:** Thu Dec 04, 2014 12:37 am

No problem. I'd just PM him if he doesn't see this soon enough to make sure of what he runs. It's an extremely easy install. Doing it in your driveway should take the weekend tops.

GlowingBulb · **Posted:** Mon Dec 08, 2014 12:20 pm

Bmxer that helped a lot, really appreciated!!! I think UK states offset usually as I've never really encountered backspacing until I bought a Jeep & joined here.

Bmxer524 · **Posted:** Mon Dec 08, 2014 1:16 pm

From what I've seen trucks generally use backspacing, and cars tend to use offset. I know it's different over seas though. Backspacing is more of a U.S. thing I believe.

tommudd · **Posted:** Mon Dec 08, 2014 3:07 pm

Backspacing / offset, front or rear wheel drive etc , all affects how they use the terms or advertise them

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