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General Forums => The Mess Hall => Topic started by: BOOGIE444 on October 15, 2007, 02:51:39 PM
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I am going to be putting a 4" lift on my 2002 TJ, its my daily driver. I have a 5 speed and right now I have 30x 9.5 x15 kumho MT's on it. I had super swamper LTB 31 x 11.5 x 15 on it before and I stuck with them until they died but my jeep was a dog and gas mileage sucked. Can I get similar performance to what I have now with 30" MT's with stock gearing compared to 4.88 and 35 x 12.5 x 15 kumho MT's??? Or do I have to step down to 33" tires? Oh I plan on getting aluminum rims too, I have steel rock crawlers that are rusted right now.
I just dont want to spend $2500 plus with lift kit, new tires & rims, and gearing change and have the thing look wimpy with just 33's. This thing will be my daily driver, and will rarely see some light off roading. I drive 10 miles to work every day on a 55mph highway. I guess I will go the 33" tire route if its going to suck as bad as it did with those big & heavy 31" LTB super swampers.
Any help would be greatly appreciated as I am a noob with all this stuff.
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Gas mileage is going to suck even more with bigger tires
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The lift will increase your wind resistance and degrade your mileage too. 33's with 4.88 seems to work well for many and will not look wimpy but your mileage will never be as good as stock.
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You want stock like performance with 35's, you're going to have to regear to 5.13's or 5.38's. That's the sweet spot to shoot for on a 2.5L. You can run 4.88's but you'll really want to go lower. Although that requires an axle swap. You'll probably want to consider an axle swap or upgrade of some kind to beaf up the rear axle. Don't forget to address the rear driveshaft. The angle to run 35's will require a SYE. Like what was mentioned by the others, 35,s with enough lift to clear them will make your brick into a bigger brick. You'll need at least 5" of lift.
Honestly, if you want to go bit without doing too much, I'd consider going with 33x9.5R15's. They are still 33's but they are narrower so there is less rolling and wind resistance. Not to mention they are lighter then standard 33's. You won't need to regear. If you do though 4.88's would be good. You'll need less lift which means it will be a bit lower and act less like a sail. If you get the proper wheel BS your tires won't stick past the stock flares and act more like a sail.
Once you move to 35's, the Jeep becomes less of a Daily Driver. If you don't have to commute then all the better. I run 35's with 6" lift and 4.56's. Commuting was always a PITA since I don't have enough power to pass unless I really plan it ahead of time. It gets frustrating and wears you down as well. My commute was 40 miles.
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Thanks for all the replys guys, I am definatly going to steer clear of the 35's then, looks like I will go with 33's and a 3-4" lift.
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Good choice on the 33"s.
I run 35" and 36" tires, and the 5.38 gears are perfect with my 5spd. I can actually accelerate in 5th on the highway :thumbsup:
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I'm telling ya'...go with the 35's and don't look back...not even worth it to go from 31's to 33's...only a 1" lift gain....and the power loss will be negligable.
btw...I went with 4.88's in my D60's....but only because I plan on putting 300-400hp under the hood in the next year or two...
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I'm telling ya'...go with the 35's and don't look back...not even worth it to go from 31's to 33's...only a 1" lift gain....and the power loss will be negligable.
btw...I went with 4.88's in my D60's....but only because I plan on putting 300-400hp under the hood in the next year or two...
Hahah, that's exactly what my friends said when I was looking to get new tires to replace my 32's! I had just regeared to 4.56's a month before and it was sweet. Now I'm back to square one but it looks great and runs great offroad.
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I am running 35" Mud Rovers on American Racing Baja (Aluminum) rims... 4.88's you need to get a run at some of the hiway hills... but it's not too bad for me. Light tires & wheels are key. Also depends on your location/terrain...
(http://i72.photobucket.com/albums/i169/mighty4banger/Livingston/100_0620.jpg)
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I'm running 35's with 4.10's and for offroad it works fine. But he said in his first post that his jeep is a mall crawler which rarely sees even light offroading - and he was worried about mileage ;)
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Ok, now you guys got me confused again....
I dont mind not getting stock like gas milage, but I would like to get 15mph on the highway. Like I said 99% I will be driving on 55mph highways. But I would like to be able to go 70mph for the 65mph highways too, when I had the 31" super swampers 70mph was not possible and I was getting around 10-12 mpg. Right now with stock gearing and 30" kumho MT's I get about 15-18mpg and I do fine on the 65mph highways as long as there arent crazy hills. I live in Iowa so we dont have smoky mountain type crazy hills & roads.
I dont mind not having stock performance but I dont want performance that is worse than I have now. So is this still not possible with 35's????
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I dont mind not having stock performance but I dont want performance that is worse than I have now. So is this still not possible with 35's????
Nope. Any time you add larger tires, even if you compensate with gearing the performance and mileage will be worse. Especially with a motor which has no extra power to spare.
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Ok, now you guys got me confused again....
I dont mind not getting stock like gas milage, but I would like to get 15mph on the highway. Like I said 99% I will be driving on 55mph highways. But I would like to be able to go 70mph for the 65mph highways too, when I had the 31" super swampers 70mph was not possible and I was getting around 10-12 mpg. Right now with stock gearing and 30" kumho MT's I get about 15-18mpg and I do fine on the 65mph highways as long as there arent crazy hills. I live in Iowa so we dont have smoky mountain type crazy hills & roads.
I dont mind not having stock performance but I dont want performance that is worse than I have now. So is this still not possible with 35's????
Well, those Swampers are heavy tires and tall. 31's are more like 32's in height. Your mileage as well as your speedometer were off because of the tire change. In which case you were probably getting 15mpg and doing over 70mph (unless you checked it with a GPS).
Honestly, any change is going to affect the mileage. Although when I was running 32's and stock gearing I was getting some really good mileage but those were at 50-55mph. With the national hwy speed at 65mph, it's made going 50-55mph almost impossible. Also, keep track of who's saying what and where. Some are talking about offroad while other onroad. Since you're 90-99% onroad, offroad doesn't really matter as much. If you really want to run 33's then you will want to regear. Regearing won't immediately lower your mileage. It will raise your RPM's back to a usable range (near stock or a bit lower). If you tend to drive fast and rev your engine higher then that will reduce your mileage. It's the fact that you want to move your taller box just as fast as before that kills the mileage. Regearing isn't cheap though.
Stick with 30-31's if you don't want any change.
I suggest checking out the Gas mileage thread and see what people are running. Then check the FAQ. Then search some more.
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Jeffy Great answers there Bro :) they were easy to follow with all the info you need to make correct choice.
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Well it looks like 33's are the obvious choice for the 4 banger, thanks for the help guys. I almost pulled the trigger on some 35's before I joined this forum, and it sounds like I wouldnt have liked them at all for my daily driver.
Kumho MT's 33 x 12.5 x 15 = end of thread :thumb:
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Any time you add larger tires, even if you compensate with gearing the performance and mileage will be worse. Especially with a motor which has no extra power to spare.
I would have thought the same, but my setup with 35" or 36" tires and 5.38 gears average about 15mpg, with a best of 18mpg. Not bad for uber-low gears.
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couple things, the differance between 33 and 35 makes a huge change when i went from 33 to 35, that being said you can always do what i did and make an insane little 4 cylinder. i run 35's with 410s and have no problems with hills anymore. i do plan to go to bigger gears but for now it works fine. i still get 15-18mpg. but a motor build may be out of range for some, and if you can't do it shops will probably kill you with labor costs. unfortunatley to say i will be going with jeffy soon, my 4cyl will be coming out and a v8 in. i love my little motor but the plans are going much bigger and i can't say that i will keep the motor.
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I'm running 35" Toyo MT's and 4.88's. No complaints! Well maybe a few. But really for daily driving here in Oregon the combo works fine. I did have some issues with loss of power on some hills. I would hit 3rd gear to hold 55mph but with a simple ignition upgrade I rarely pull her out of 5th. The issue with clearance for the tires with 4" of lift seems like it needs to be addressed! I had to install 2" coil spacers up front to keep the 35's out of my fender flares off road. Had to compensate for the weight of winch and bumper I guess!
P.S. I average 16-18mpg and didn't have to recalibrate my speedo
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I'm running 35" Toyo MT's and 4.88's. No complaints! Well maybe a few. But really for daily driving here in Oregon the combo works fine. I did have some issues with loss of power on some hills. I would hit 3rd gear to hold 55mph but with a simple ignition upgrade I rarely pull her out of 5th. The issue with clearance for the tires with 4" of lift seems like it needs to be addressed! I had to install 2" coil spacers up front to keep the 35's out of my fender flares off road. Had to compensate for the weight of winch and bumper I guess!
P.S. I average 16-18mpg and didn't have to recalibrate my speedo
Ignition upgrade?
Could you enlighten us/me?
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I have a 97 TJ 2.5 stock with stock gears in it, Auto tranny, 4" rough country suspension lift and 33" 12.5/15 on American Racing Baha wheels. I took it on a 2 hour trip earlier this month and got 14.5 mpg. It cruised 65-70 fairly easy. The cross winds suck even though I have a new steering stabilizer on it. I was fighting to stay between the lines at times. I have 7" flares on it and the tires only stick out about an inch or so. Good luck with what ever you decide to do to your Jeep.
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I'm running 35" Toyo MT's and 4.88's. No complaints! Well maybe a few. But really for daily driving here in Oregon the combo works fine. I did have some issues with loss of power on some hills. I would hit 3rd gear to hold 55mph but with a simple ignition upgrade I rarely pull her out of 5th. The issue with clearance for the tires with 4" of lift seems like it needs to be addressed! I had to install 2" coil spacers up front to keep the 35's out of my fender flares off road. Had to compensate for the weight of winch and bumper I guess!
P.S. I average 16-18mpg and didn't have to recalibrate my speedo
Ignition upgrade?
Could you enlighten us/me?
No problem. Instead of going with the Screamon Demon Kit, I got a hold of a MSD coil, Mopar performance wires, NJK U groove plugs gapped at .055", And Bosch cap and rotor. Simple upgrade cost about $140.00. Oh yeah I had to splice a older style plug on for the coil. Any particulars can be answered at www.backwoodsoffroad.com. Evan is pretty knowledgeable
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Thanks gary.
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You bet!