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-   -   Decreasing Lift / Tires for MPG (http://www.wranglerforum.com/f19/decreasing-lift-tires-for-mpg-57163.html)

aermotor 08-04-2010 01:10 PM

Decreasing Lift / Tires for MPG
 
So I recently picked up a used 2007 Sahara with what I believe is a 6" lift and it's almost too much for me. Does anyone know a ballpark cost to reduce the lift to 3" or 4"? I'm not too sure how mine was lifted as this is my first vehicle with one; can it just be shortened with what it has or does it need a whole new lift? I attached a few photos so you guys can see what it's got.

Also, it currently has Mud Terrain KM2 35x12.5x17 tires on there which are pretty worn down, some of the tires are quite uneven. Is it better to go with a nice A/T tire to help out my gas milage instead of replacing the tires with the same KM2s? I won't be doing anything too crazy with this so I think the KM2s are overkill.

I'm pretty sure it's got after market gearing as well, I just don't know what as no paperwork came with the car... I assume this will affect gas milage as well? The Jeep seems to love 70mph on the freeway and on flat drives does it at 2K RPMs.

Thanks for any help, I'm so glad I found this place!

Front
http://aermotorstudio.com/jeep/1.jpg

Rear
http://aermotorstudio.com/jeep/2.jpg

Front
http://aermotorstudio.com/jeep/3.jpg

Front
http://aermotorstudio.com/jeep/4.jpg

Rear
http://aermotorstudio.com/jeep/5.jpg

daggo66 08-04-2010 01:32 PM

You would need to purchase an entire new lift kit to go lower. That's pretty high for 35's. What is your current MPG? Switching to AT tires will make a difference. Going down to 33" or 32" tires will make a much bigger difference. The lift itself will only make a minor difference. I'm betting you have after market drive shafts with a lift that high. Can you take a picture of them?

schnutzy 08-04-2010 01:34 PM

that looks to be a 4 inch rough country suspension kit that you have there.

schnutzy 08-04-2010 01:38 PM

actually scratch that. i looked closer at the control arms in the last pic. it is definitely a rough country kit, but it could either be the 4 inch X kit or the 6 inch X kit.
if you post a shot of the whole jeep we could probably tell ya which.

clear lake jeepn 08-04-2010 01:39 PM

Lower and Jeep should NEVER be used in the same sentence. My chrystal ball tells me there is a Prius in your future!

aermotor 08-04-2010 02:03 PM

From AZ to CA I got 16mpg and in town I think it's even less :banghead:

Reducing the tires to 33s will bring the whole thing down a little bit, but would those look dumb on this lift?


http://aermotorstudio.com/jeep/full.jpg

Front Shaft
http://aermotorstudio.com/jeep/drive1.jpg

Rear Shaft
http://aermotorstudio.com/jeep/drive2.jpg



Quote:

Originally Posted by clear lake jeepn (Post 712284)
Lower and Jeep should NEVER be used in the same sentence. My chrystal ball tells me there is a Prius in your future!

Ahahaha!!! Hell no! This thing is just massive and I'm not used to it yet.

daggo66 08-04-2010 02:15 PM

Yes, 33's will look dumb with that lift. I only suggest that if you are looking at a smaller lift. Those are stock drive shafts. The opposite end of each is where you could have a rubbing issue with the CV boot, especially if you have an automatic. 16 MPG with that set up isn't bad at all.

aermotor 08-04-2010 02:19 PM

Yea I see hat you're saying. I've already got a brand new full size spare w/ a KM2 35 on it, so I'd only have to buy 3 new tires and I'd be golden. Then just swap the best used one onto the spare.

Should I have this looked at before I go to get new tires/alignment?

daggo66 08-04-2010 02:23 PM

It's not a problem, just something to be aware of. If the boots get torn, the shaft won't last much longer. It's a bigger issue with auto trannys.

yj-genral 08-04-2010 02:35 PM

you can call rough country and see if you cant buy the shorter springs for the 4" lift... alot of the kits nowadays are similar if not exact same parts with the exception of springs and shocks... i'd call and check if you could swap them out and it will lower it 2" roughly... and if you wanted to 33" would help but i would think about your gears.

if you have the stock gear then your engine is burning more fuel trying to move the big tires. if you regear correctly you can end up getting pretty close to stock mpg again. but dont think you will ever see 20 mpg :D i get about 16mpg around town and 18 on the highway... your not that far off.

daggo66 08-04-2010 02:40 PM

I don't think he has stock gears if he's running 35's and only 2K RPM at 70 MPH.

aermotor 08-04-2010 02:52 PM

yea I would really be surprised if they are stock... I've driven a stock Sahara on a dealership lot and it had surprisingly sluggish acceleration whereas my beast gets a move on it fast. It's also got a custom dual Gibson exhaust which helps some.

FREDO 4X4 08-04-2010 03:11 PM

This is the second post i scene lately about lowering jeeps. I hope this is not contagious.

Next we are going to see jeeps like this in our town. OMG i cant even look at this picture.

http://www.streetsourcemag.com/uploa...r/Mvc-005s.jpg

yj-genral 08-04-2010 03:19 PM

i just wonder how they get in that thing... with no door latch and no power door locks for a electric system... you like the flush tailights? i say take the top and doors off and cruise that bitch :D

HotTinRoof 08-04-2010 03:31 PM

Quote:

Originally Posted by yj-genral (Post 712423)
... i say take the top and doors off and cruise that bitch :D


A wrangler T-bucket? :rofl:

aermotor 08-04-2010 04:00 PM

Quote:

Originally Posted by yj-genral (Post 712377)
you can call rough country and see if you cant buy the shorter springs for the 4" lift... alot of the kits nowadays are similar if not exact same parts with the exception of springs and shocks... i'd call and check if you could swap them out and it will lower it 2" roughly...

I called Rough Country and they said just replacing the springs would do it. About $325 shipped, so that's an option down the road if it doesn't grow on me.

KBR97 08-04-2010 04:34 PM

you could get the smaller springs from Rough Country and then replace the 35s with 33 all terrains.
You gas will then improve...some.

aermotor 08-04-2010 06:10 PM

Yea true. I think I'm going to leave it is for now and just get my new tires on and deal with it. I don't drive too much so it's not that big of a deal. But living in LA you know how that can be... everything is not close together and I live up in the Foothills.

Thanks for the suggestions everyone.

G54 08-04-2010 06:42 PM

Quote:

Originally Posted by daggo66 (Post 712382)
I don't think he has stock gears if he's running 35's and only 2K RPM at 70 MPH.

Sounds like a possibility to me. If the PO had re-geared to a lower ratio compatible with 35s, like 4.88 maybe, it would be running at closer to 2500 or maybe more at 70mph wouldn't it? Or am I confused?

I'm thinking I had 3.73s and 33s and ran about 2000 rpm at 60mph in 6th gear. Now with 4.10s I'm hitting about 2300 at the same speed and 6th gear. Much better for the Jeep and for performance.

InfernoGirl 08-04-2010 07:16 PM

Quote:

Originally Posted by aermotor (Post 712576)
Yea true. I think I'm going to leave it is for now and just get my new tires on and deal with it. I don't drive too much so it's not that big of a deal. But living in LA you know how that can be... everything is not close together and I live up in the Foothills.

Thanks for the suggestions everyone.

Make sure to have an alignment done with the new tires, and rotate regularly, since you mentioned they are wearing unevenly.

aermotor 08-04-2010 07:27 PM

Yea for sure, that's what I'm doing tomorrow. Who knows how long these KM2s have been on there or what they have been through, but they are pretty low and the fronts definitely have some strange wear on them. Thanks.

daggo66 08-04-2010 10:34 PM

I think you're making the right choice by sticking with the lift you have and adding new tires. Lets' say you went done to 33's, what would you gain 2 to 3 mpg? In the grand scheme of things I don't think it would be worth it. It's not like you're going to gain 10 to 15 mpgs.

aermotor 08-04-2010 11:29 PM

Yea you're right. Even if I I got 2mpg back that's roughly 30 miles extra per tank which is only a savings of 2 gallons or $6... It would take over 100 fill ups to recoup the cost of decreasing the lift and different tires.

I love this site.

HotTinRoof 08-05-2010 09:50 AM

Quote:

Originally Posted by aermotor (Post 712952)

I love this site.


:punk:

aermotor 08-05-2010 06:56 PM

Hey guys, looks like I spoke too soon on my actual RPMs were... didn't know at the time that was supposed to be measured in 4th gear (automatic for me) Anyway, when in fourth gear going roughly 65mph I'm looking around 3050 rpm which doesn't look very economic on the charts... Re-gearing is most likely too much for me right now, but I'll at least explore other options that might help my MPG out.

InfernoGirl 08-05-2010 07:48 PM

If you haven't had the speedo calibrated for the size tires you have, then the odo is off too which is giving you false mpg readings. Check your speedo with a gps and that will help you figure more accurate mpgs. But, it's a Jeep.... no matter what you do to it, it will never get good mileage unless you leave it in the garage.... :)

yellowjacket 08-05-2010 08:41 PM

Its like a women getting a brest reduction jeeps grow not get smaller.

aermotor 08-06-2010 12:21 AM

Contrary to popular belief, breasts CAN be too big sometimes!

aermotor 08-06-2010 12:37 AM

Got my new KM2s put on today and boy does that make a huge difference! These ride really well and aren't that loud at all. Great tire!

FNjeep 08-06-2010 12:38 AM

Copy that aermotor!


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