Anybody running 31's with a 3.07? -
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Go Back > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > Anybody running 31's with a 3.07?

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Unread 06-04-2002, 05:29 PM   #1
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Join Date: May 2002
Location: Grapevine, Tx
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Anybody running 31's with a 3.07?

I've got a 6 cyl. w/ a 5 speed and a stock 3.07 axle. I'm wanting to move up to a set of 31x10.50's and wonder how this will effect hwy. driving. I'm a flatlander, but may occasionally take it up to the mountains. Right now, in 4th gear, she runs at about 2250 rpm. Has anyone with this axle made this change? Is it worth the expense to regear if I'm going to stay with 31's for a while?

Thanks for all the help.


'99 TJ, 4.0 6 Cyl, Sport, Gunmetal Blue, 5 Spd, Fog Lts, R. E. 2” lift, Kumho 31x10.50 Venture MT, ARB Lockers ORF Sport Cage, Rock Crusher Rocker Protectors, Olympic front and rear Rock Bumpers, York On-board air, K&N Air Filter, Mirror Relocaters, Sailcloth Top, Trail Cover, JKS adjustable disconnects, Uniden 510 XL CB w/ Firestic II, Hi-Lift, Warn XD-9000 Winch
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Unread 06-04-2002, 05:57 PM   #2
Dan Morera
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Location: Costa Rica
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I have 31"s with 3.07 and it's not that bad. But I'll bet it will be nice to regear. Maybe in a couple of months.

Don't rush it. I live in a place with alot of mountains and no mayor problem.
YJ Sahara 88, 258 I6, BA/10
2.5" Susp. Lift (Aprox.), 1" Shackles 31x10.5" Cooper
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Unread 06-04-2002, 08:21 PM   #3
Bob K
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Agree with Dan. Power is still more than adequate if your engine is running properly. I wish my gears were lower, particularly on the highway when I have to downshift for long hills or acceleration. Regearing is about $1000 parts & labor. I don't think it's worth the $$. Some might feel differently.
'87 Wrangler YJ 4.2 I6 (sorry, sold)
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Unread 06-04-2002, 10:24 PM   #4
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I have 32's with 3.07's and with a modified aribox k&n and no restrictor its not too bad but when i bought it it had 31's on it and i had no problems even got it to do 100 a couple of times don't waste the money on a regear, if you want do some small engine stuff (intake maybe exhaust) and you'll be fine
Black 2012 JKUR 2.5" Rock Krawler Max Travel suspension with Bilstein 5100's, 35X12.5R15 MTRK's on MB Ultras, Sleeved and gusseted front axle with Synergy balljoints, JCR bumpers F/R

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94 Green YJ SE 4.0L 5spd
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Unread 06-05-2002, 10:44 AM   #5
Prime Lord
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Question for you guys w/ 31's and 3.07's.....what do you get for gas mileage?? I'm gonna be running like that shortly & want to know what to expect.
[url=""]'92 YJ Islander[/url], 4.0, 5-speed. 1" Daystar Body Lift, 31x10.50 Goodyear MT/R's, CJ Style (87-91) Roll Bar, ARB Safari Snorkel, K&N Panel Filter, Dynomax SuperTurbo Catback. Still hunting for TJ Sahara flares!!!

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Unread 06-05-2002, 11:39 AM   #6
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I am running 31's and 3.07 gears. They are not that bad on the street, but off-road the better gears are needed.
The gas milage is about 225-280, depending on how much city driving I do.

Eople may say that you do not need to re-gear. If yo uare never planning ot go off-roadm then they are correct. But when I go off-road, going up hill or up rocks and such, 3.07' suck. You end up using a lot of clutch, which burns them out. My $.02 is to save your money for a few months and do the re-gear. You will definately notice the difference on the trails and on the highway.
94 4.0L YJ, 31x10.5 ProComp MT's, 3.5" BDS, lockers and 4:56 gears to come!
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Unread 06-06-2002, 12:53 AM   #7
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i recently put 31's on my 3.07s.. mileage is for crap.. i'm gonna do 3.73's to handle the 32-33's i'm eventually putting on the rig, as well as cat back exhaust and MSD ignition.. should bring the power and mileage back up from the low teens back to the high teens/low twenties.. check out the latest edition of JP (july 2002) there's a wrangler in there w/ 31's and 3.73's getting about 22mpg
Awwwwwwwwwwww... So he wants to go OFF-ROAD does he????

'93 YJ, 4.0, K&N filter, Borla Header, Borla Cat-Back, Hi-Flo Cat, 3 Core Radiator, D-Rings, TruckNuts, MSD 6A, LockRite Locker in D30, Magnecors, Kickass Stereo, 1" daystar, 31" BFG AT's, Homemade Rocker Guards and Front/Rear air-tank bumpers with tire carrier, 15x8 AR-767 4"BS, BDS 3.5 HD lift, AMA A/C Kit, York OBA, GoFerIt 1" MML, 8,000lb HF/MM Winch, Magellan MAP 330 GPS, PRO-2067 500ch. Scanner, oh, and a CB capable of talking to SATURN!

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Unread 06-06-2002, 01:12 AM   #8
93 Blue Demon YJ
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well I got about 24 MPG running 32's with 3.55 gears. That was in the mountians of montana where the air/fuel mixture is leaner. back down here at sea level, I get about 17-18, but have much more power.
'93 YJ 4.0 3" RC lift 15x10 wheels and 32" tires.
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