Topic: Another guy with gearing question

[Moondo]

I did try searching the site for my answer before posting, and it appears that the previous answers are too old and the links no longer come up. So here it goes.

I have a 1997 Wrangler with a 2.5L and 3 speed Auto with 31" tires. This is my daily driver I have no intentions of going bigger with the tires. I drive a 50/50 mix of city and highway driving. I am not concerned with mileage, But I do want to keep up with highway traffic at least 70 MPH. I was wondering what setup has worked out the best for you guys? 4.11's, 4.56's or 4.88's with 31's and the auto tranny?   Thanks. 

[sharpxmen]

you should be fine with 4.11 if you don't go higher than 31'', i think 4.56 would give you like stock final ratio (including the tires), not 100% but 4.88 and 33'' it's pretty close to stock (from what i remember). I looked at a table in the faq section for speedo calibration and you can work the gearing out of that as well.

[andrew383]

id say stock 4.10's if its 31's.I ran 31's and 4.88's with a 5speed and runnin 70mph would have been 3500rpm+

[jfrabat]

id say stock 4.10's if its 31's.I ran 31's and 4.88's with a 5speed and runnin 70mph would have been 3500rpm+

I dont remember my RPM's going that high when I ran 31's with 4.88; IIRC, mine was more like 3~3.2K...

[Moondo]

So if like stock was 4.10/4.11 on 31's, could I go with 4.56 for a little more pickup without running too high of rpm's at 70 MPH? Is there that big of difference between 4.11 and 4.56?   

[neale_rs]

Let's say you started with 28" tires and then went to 31".  The 31s are 10.7% taller.  You would want 10.7% lower gearing (numerically higher) to compensate and keep your speedometer calibrated.  4.11 + 10.7% of 4.11 = 4.55 so 4.56 would be just right.  You can also go a bit lower to make up for the extra tire weight and air resistance, so you could go with 4.88 but you would also need to correct you speedometer.

[jfrabat]

In all honesty, I feel that if you are going to regear, you may as well go to 4.88.  It is a big investment, and the change from 4.10 to 4.56 is minimal.  Also, the 4-banger is capable of running at 3K RPM all day without problems, so this will mean that you can stay on 5th for slight uphill sections of the interstate, and you can also stay in 5th when there is a head wind.  I was actually very happy with 4.88 and 31's, and now that I have 33's, I feel a bit underpowered (I would love to go to 5.13, but that means 2 new axles!).

[jcsanders79]

I have an auto with 4.88's and 33's I have no problem going 70.

[jfrabat]

By the way, if you DO go 4.88 and 31, be advise that you will have a hard time finding the right speedo gear;  IIRC, you need a 44 tooth one, but the highest tooth count I found was 43 (not sure on the numbers, but I found one that was one tooth short, which meant my speedo showed I was going about 6~7% faster than what I really was going).

[Moondo]

Thanks guys, that is exacltly what I was looking for.   

[sharpxmen]

By the way, if you DO go 4.88 and 31, be advise that you will have a hard time finding the right speedo gear;  IIRC, you need a 44 tooth one, but the highest tooth count I found was 43 (not sure on the numbers, but I found one that was one tooth short, which meant my speedo showed I was going about 6~7% faster than what I really was going).

seen somewhere an aftermarket electronic calibrator for the speedo signal - if i go to 35s i will probably buy one of those, can't remember the price though so that might be a problem

[jfrabat]

seen somewhere an aftermarket electronic calibrator for the speedo signal - if i go to 35s i will probably buy one of those, can't remember the price though so that might be a problem

I hink you are talking about the Superlift TruSpeed; but I did not want to pay $200+ for a speedo corrector (I could have the correct speedo gear custom made for less, but this was still too expensive for me).

[TahoeYJ]

In all honesty, I feel that if you are going to regear, you may as well go to 4.88.  It is a big investment, and the change from 4.10 to 4.56 is minimal.  Also, the 4-banger is capable of running at 3K RPM all day without problems, so this will mean that you can stay on 5th for slight uphill sections of the interstate, and you can also stay in 5th when there is a head wind.  I was actually very happy with 4.88 and 31's, and now that I have 33's, I feel a bit underpowered (I would love to go to 5.13, but that means 2 new axles!).

Screw being overgeared. Don't be a wimp, run 4:88's with 35's like me  Granted I downshift when I hit steeper inclines, I still run 75+ on the highway most the time.

And you're right, the 4 banger can definitely deal with running at over 3K RPM's. When I run on the interstate I'm usually cruising around 75, and I'm around 31-3200 all day long. I've even been in 4th gear uphill for long periods of time in excess of 3500 RPM's without issue