Topic: Interesting observation

[aw12345]

I have ran several different brands of tires and made some interesting obxervation, the most important one is that roll resistance of the tire is very important for a 4 banger. Stone stock Jeep got 19 mpg on the factory donuts dropped to 18 with bfgoodrich at's and the stock3.73 gears. Then lifted it and regeared it to 4.56 did not like the way it ran with the 31's so put 33" cooper stt's on, they wheel good but have a high rolling resistance and chunk easily also milage went to 14 mpg. Then I sold those and went to 32"x 11.50 goodyear mtr's those wheeled well and milage went up to 16-17 mpg, Now I run Mickey thompson baja mtz's 35 x12.50, those things are 13' wide and guess what wheel great still like my 4.56 gears, I shift more but with the 6 speed going through mountain passes on the highway and going to Big bear the gearing is just right 3th and 4th was always a bit to short and now they are perfect also milage is still16-17 mpg actually closer to 17-18 mpg go figure. These things roll really quite easily it coasts much farther then the previous 2 sets of tires in other words I love these tires. Now the moral of this story is try to fing good offroad tires with a low a rolling resistance as possible different tires make a big difference

[jcsanders79]

Hmmm.  Don't know never kept up with the milage since I went non daily driver.  I think the straight shifts get better milage than us auto's.  I'm thinking new tires soon and have reached a conundrum on going 35" or staying 33" (and tourch I'll have a D-44 up front soon ).  How do the 35's compare to the 33's?  I've got 4" suspension and 1" body if that matters.

[aw12345]

35 mtz's measure 34" and are 13" wide. I have a 2.4 l engine 6 speed and4.56 gearing and I like the 35's.
it basically acts the same as running 31 bfg  at's with 3.73 gears. I have to shift a bit more betwen 5th and 6 th
Still it does 65 in 4th at about 35rpm up a fairly steep mountain pass. In other words I can keep up with my buddies with 6 cyl's regeared and on 35's. That was the most important thing to me that the milage did not drop off is an added bonus since I drive my beastie every day to work

[jcsanders79]

I've got 4.88 and want 5.13 or 5.38 (haven't decided yet).  How much lift do you have?  Obvious you Jeep flexes well!

[aw12345]

It's a mix mass of parts RE 3 1/3 springs currie control arms upper and lower and currie trackbar up front as well as a currie antirock swaybar that stays connected while wheeling in the rear currie lower control arms and a fulltraction trilink makes for good flexing front and rear

[oldjeep]

I've been happy with the MTZ's as well.  Great compromise onroad/offroad tire.

[dexetr30]

I'm up for some new shoes soon. I'll be switching from BFG A/T's back to a passenger all seasons for a while. Reason being, I don't have the cash right now to fix things that get broke out on the trail. So, I'll be trail free for a while with the exception of maybe some back woods dirt roads and similar things. I'll be switching to a set of Kumho Solus KR21's, 235-75-15's. They're the same size tire I'm running now (29"s) so I won't look goofy going down the road. They're actually about 10lbs. lighter so this will greatly reduce my rolling resistance. I'm hoping to regain some m.p.g. because of this. Being my D.D. we put a lot of miles on the Jeep and the A/T's didn't hold up very well, they they did great on the trail. The Kumhos have an 85,000 mile tread wear warranty. I know this isn't a typical Jeep/offroad tire but it's what I'm going with for now. Need to save some cash and at $68.00 a tire + M&B, you can't beat the price.

[TahoeYJ]

I averaged about 17 on stock-ish 235's and nothing more than a K&N Filter. Went to 33's, it dropped down to about 13-14 city, and maybe 15 highway. 4:88's helped some, but it was still maybe 16 max. Added the 4.0 TB and it gained me a bit more. After swapping to my current 35" MT/R's my mileage went up again, which surprised me a bit. At this point in time I'm getting about 16-17 in town, and 17+ highway.

aw12345 do you have the 2.4 or 2.5? You must have the NSG-307 (I think that's the name?) 6 speed? Only reason I ask is because I've read that swapping it to an older 2.5 like mine will be a PITA, and I'd LOVE to have a 6 speed. Jeep must have made it an option with the 2.4 I take it? I'd love to try and swap one in eventually, I think it'd make the 4 cyl even more driveable up and over the mountains.

[aw12345]

Yes it has the 6 speed, not the nicest shifting tranny but I love it. Especialy for mountain driving. Also it has a fairly low first gear ratio which I loke for crawling combined with the terra low it does very well on rocks.
They have done swaps on the 4.0's with this trans I guess the difference is the location of the crank sensor
They came as a stock trans on the 2005 and 2006 models, don't know about 2004

[TahoeYJ]

I think it'd be fun as hell to have 6 gears to smash around in, especially up in the mountains  I plan on moving back to Tahoe in a couple years, it'd be sweet to have the 6 speed up there. Sometimes even 4th is too high geared on steeper grades, plus my squirrels don't have as much air to breath up there...

I've heard the shifting isn't the greatest, but I could live with it. Still have yet to drive a Jeep w/ one though...

[aw12345]

Compared with a ax15 it shifts stiff and a bit scratchy but I like the gear spread works well. So Cali has a lot of mountains and hills with the current gear setup it works quite well for me. Also the overdrive is not as big a step as the NV3500, the ax15 and the ax5

[stan98tj]

16mpg+?!!!!!!!! wtf!!!??? man i really envy you guys. ive been trying to squeeze as much gas out of my TJ since i got it. it was at 8mpg or so before the engine blew when i first got it. even with the AEM cold air intake, 62mm TB, TBspacer, upgraded cat back exhaust im still averaging only 11-12mpg (if im lucky) highway. and all im running are 31s...i know my auto tranny doesnt get as good mpgs as the manual but nothing ive done thus far has really helped..but 16mpg+, i hear a lot of the dudes on the forum getting that with larger tires than mine and im blown away...id kill for 14mpg! i wish i could make the jump to 16+, gotta be something im overlooking...

[FourbangerYJ]

For some reason I thought you had an auto Art. The 6 speed would be nice. I like the lower 1st gear.
Intersting find with your new tires. They look good on your Jeep. Not sure what I will do next go around on the tires. I have awhile to think it over.

[aw12345]

The guy I got the tires from put bf goodrich krawlers on his those things look badass and are big.
The 35's look really nice, makes the lift just look rightand everything just clears nicely. It takes some of the fun out of wheeling though, you go any bigger than that and almost any trail becomes easy, makes a heck of a difference compared to my 32's

[aw12345]

Stan does the torque converter clutch engage? If its the 4 speed automatic I guess the overdrive is a little to steep to work well. Even the 6cyl automatics get poor milage, did you correct the speedo though? When you put bigger tires on the speedo shows less miles than actually traveled