I have a 2001 Jeep Wrangler Sport I6 3-speed auto. It came factory with 3.73s and 30" tires. I now have 33x12.50 tires and I have lost acceleration, especially uphill. With the A/C on, it's horrible.
My main concern is on-road. Off-road 4 low works like a champ. It's getting to the trail, that's the problem.
There seems to be 2 issues. First, larger tire diameter means more tire roll-out which lowers the engine RPMs at any given speed. Second, larger tires weigh more which increases rotating mass that robs torque.
I am going to regear and need to know which ratio to get. Looking at gear charts, 4.10s will get my RPMs back to what it was with factory 30" tires (2788rpm). Problem one solved.
However, my new 33s and wheels are substantially heavier (like 14-16 pounds each, if I remember right). Would I need to go to 4.56 make up for this added rotating mass?
The charts say 4.56:1 will run the engine at 3099rpm at 65mph! That's gotta suck. However, it would be disappointing to go to the expense of regearing to 4.10s, to regret not going to 4.56s.
Due to your 3-speed auto, 4.10 is the way to go for 33" tires. After I converted my 4.88 and 35" tire equipped TJ from the 5-speed manual to 3-speed automatic, I had the same rpms your chart pointed out it'd have with 4.56 and 33" tires. Not bad but a little too high. 4.10 will be ideal, unless you think you may eventually get to 35" tires in which case I'd regear to 4.56 since the rpms aren't THAT bad... once you get used to them at least.
x2, I have the 32RH 3 speed auto and 4.10 gearing, turning 33" tires. Jeep runs well on and off the roads. I am happy with the setup, at 55mph - I believe my RPMs are under a tad of 2500.
That's what I have. Not bad. I have no problems running at 75 on the highway (but I don't...) it's not a speedster that's for sure but it's not nearly as bad as some I've ridden in. In the end it works but probably isn't ideal.
I am also running 33s on stock 3.73 and it is a bit of a slug as well... looking for an HP 30 and an 8.8 to get the stock 4.10s and then I will regear after that I am thinking
I have the 32rh, 6cyl, and 3.07 gears and was actually considering 3.73 as the best gearing for me (95% road). I really don't have a whole lot of problem on the highway, but it's pretty flat around here in the Mississippi delta. I turn 2500 rpm at 75 mph now. I don't want to get out of the powerband running 75 mph with 4.11s. Thoughts anyone?
ok....i have 98 tj...5sp...6cyl....4.56 gears..running 33x12.5x15's and this is a pic of it doing 70MPH per my GPS and its not turning that high of RPM. id the tach off like the speedo?
Holy crap . Did you change your speedo gear????? My 98, 5sp, 6cyl, with stock 3.73's and same size tires as you only gives me a 4mph difference on the speedo. So when it shows me doing 65 I am actually doing 69 ( confirmed by the 74 in a 65 speeding ticket dropped down from 80 I got).
I am looking to go to 4.56's at tax time and will need to know which gear to buy to correct the issue.
As far as driving. I can hit a bridge here doing 70 and by the time I get to the top I got p!$$3d off people cussing me and am doing about 54. If I get a head wind I am screwed....:rofl:
I was thinking of reagearing and running 32s on my 06 automatic tj and i was told it would be better if i regeared to 4.56 not 4.11s. Was this guys wrong?
How so? I kind of know what you're talking about I think. And I have 3.73 with 33s and I use 5th on the interstate. Going up long hills you lose a lot of power and momentum but otherwise it seems to be alright.
ok....i have 98 tj...5sp...6cyl....4.56 gears..running 33x12.5x15's and this is a pic of it doing 70MPH per my GPS and its not turning that high of RPM. id the tach off like the speedo?
Wow that's crazy! Your speedo is off because I assume you never swapped put the speedo gear did you? Other wise that's exactly where my rpm sits at 70mph.
nope never changed the speedo (yet)...but that shouldnt effect the tach should it? BTW at 70mph i had a lot of power left..very impressed with this set up.
I was thinking of reagearing and running 32s on my 06 automatic tj and i was told it would be better if i regeared to 4.56 not 4.11s. Was this guys wrong?
Nope. You may even go to 4.88 but I would wait and are what Jerry says. You have the 4 speed auto that has a very steep overdrive gear so you need more gearing to turn those tires. The OP has the 3 speed with no overdrive so he needs less gearing.
I have a 97 sport with the 4.0 and a newly swapped 32rh 3 speed auto/ I am running 35s with 4.10 gears and I am really happy with it. At 70 mph I'm right around 2600 rpm.
Quote:
Originally Posted by Yellow_Fox I was thinking of reagearing and running 32s on my 06 automatic tj and i was told it would be better if i regeared to 4.56 not 4.11s. Was this guys wrong?
Do 4.88s. I just put them on my 04 auto TJ with 32s and it is perfect. You can do 4.56 if you want, and will be okay, but don't put 4.10s in it.
o ok because i didnt know exactly how everything worked and when i saw him talking about it i thought what the guy told me was wrong and i didnt kno the sticks didnt have overdrive. so would the 4.88 be better for the car in fuel economy, and giving me better pick up?
How so? I kind of know what you're talking about I think. And I have 3.73 with 33s and I use 5th on the interstate. Going up long hills you lose a lot of power and momentum but otherwise it seems to be alright.
I don't use the interstate too often and all of our highways are 55mph. It sucks lol. But even around town I felt like it was kind of struggling in 3rd to sustain 25mph. Idk I'm extreme happy with my 4.56 for the mountainous driving around here. The thing is especially torquey on take off if I want it to I squeaked the tires on a left hand turn into traffic lol. This weekend I hit 75mph on an interstate and it definitely had more go left. Also at Rausch is where my 4.56s really shone. I was just idling in 4lo and 1rst over EVERYTHING.
Yea I'm sooo jealous lol. It's 25 though town here too and I just normally use 2nd gear. I runs at about 2000-ish rpms and I think it's fine. In 3rd it feels like it's lugging. But yea, I ONLY use 5th at 65mph+. Other than that, I use 4th because there's no power in 5th. I really wanna regear, but dang it's expensive lol.
Do 4.88s. I just put them on my 04 auto TJ with 32s and it is perfect. You can do 4.56 if you want, and will be okay, but don't put 4.10s in it.
o ok because i didnt know exactly how everything worked and when i saw him talking about it i thought what the guy told me was wrong and i didnt kno the sticks didnt have overdrive. so would the 4.88 be better for the car in fuel economy, and giving me better pick up?
nope never changed the speedo (yet)...but that shouldnt effect the tach should it? BTW at 70mph i had a lot of power left..very impressed with this set up.
I also have 2000 wrangler sport 3 speed auto with 4.10 gears. At 70mph my tach is around 3k-3.1k rpm. Is this rmp revving too high? Or my I should of gone with 4.56 gears to bring down the tach rmp? Im confused...
I also have 2000 wrangler sport 3 speed auto with 4.10 gears. At 70mph my tach is around 3k-3.1k rpm. Is this rmp revving too high? Or my I should of gone with 4.56 gears to bring down the tach rmp? Im confused...
Correct, it isn't a static mph number. It is a static ratio or percentage number. For example if it's 10% off it is always 10% no matter how fast you go. At 50 mph it would be off by 5 mph, at 70 mph it would be off by 7 mph.... etc...
i use 3.07's and i dont really notice a difference... but then again i don't floor it when i'm coming out of a stop sign or red light... i dunno... maybe i'm crazy
i use 3.07's and i dont really notice a difference... but then again i don't floor it when i'm coming out of a stop sign or red light... i dunno... maybe i'm crazy
I think they are stock 3.07, but who knows what the PO put in.
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