Gear ratio poll for 37” tires on 17” wheels 3.6 gasser

[Wheelin98TJ]

Agreed, I don't know why people obsess over 8th gear so much. The 8 speed is way better then the JK 6 speed. And the double over drive, 7th gear is fine at the correct rpm and can get good gas mileage.

Because they aren't in 8th gear enough.

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[JTGuy]

The correct re gear will help save the trans.

 

[Sikjeep2]

Because they aren't in 8th gear enough.

Which doesn't matter, not end of the world if you are not in 8th gear. Go drive a JK and you gonna cry because you are only in 6th.

Yes, for sure helps from lugging at lower speeds which saves the transmission and from heat. But that can be controlled too by your foot.

 

[Wheelin98TJ]

Which doesn't matter, not end of the world if you are not in 8th gear. Go drive a JK and you gonna cry because you are only in 6th.

Yes, for sure helps from lugging at lower speeds which saves the transmission and from heat. But that can be controlled too by your foot.

You should be in 8th gear when cruising a flat highway, no wind, no load, and not trying to accelerate. If you're not, you're geared too tall or something else is wrong.

A 6 speed cruising in 6th gear is perfect. It's not cruising in 5th or 4th.

 

[ttn333]

Was on 4.10 and 37s (Toyo R/T and now Baja Boss AT) for a couple of years. Daily driving was fine. I know it's slow so I don't stress over it. Didn't even think about 8th gear, only when I read about it on here. But going up the mountains on the weekend was a little sucky at times. Then I bought a trailer. First time pulling that 2000lb load up the mountain was when I decided to make the appointment for regear. Been running 5.13 for the last 8 months or so and couldn't be happier. Daily driving had more oomph comparatively. I also run a heavier load with bumper/winch, canopy/rtt, fridge and drawer. I would not go less than 5.13. Sometimes feel like 5.38 might do better up the mountain with my relatively light trailer. MPG was never good for me. It is worse now. 5.13 makes it more fun hitting that pedal a little harder. Also run a pedal commander.

 

[Panthers65]

Not 100% clear on this but it was explained to me when I regeared mine that in order to do 5:13 gearing it needs to be made thinner in order to fit into the stock housing and they are very prone to breakage.

Someone fed you a line.... I installed my 5/13's myself. Spicer 5.13's bolted in absolutely no problem. Dana actually does a really good jobs and all their gears are +/- 0 so they all set up with the factory shim thickness.

 

[human29]

Someone fed you a line.... I installed my 5/13's myself. Spicer 5.13's bolted in absolutely no problem. Dana actually does a really good jobs and all their gears are +/- 0 so they all set up with the factory shim thickness.

Either way the 4:88 was the right choice for the 8 speed and 37s. restored back to factory shift patterns and on road RPM. The shop that I took this to was just doing the install as I was buying the gears elsewhere so it did not matter to them. Just took the advice of this jeep shop that does 2 -3 regears a week.

 

[dayusmc]

So the short of the long OP is that what gears you install or don't is very specific to your needs, there is no set rule.

If you add weight and live in an area with a lot of hills you might want to go with the 5.13s. If you live in a flat area and didn't add a lot of weight to your jeep you might want to go with 4.88s.

My wife's JLU High-Tide came lifted with 35s on it from the factory and 4.56 and I think that combo is perfect!

As I said before, I would try the Banks Pedal Monster first. You might find with that you don't need to change the gears. My Mojave has 4.10s and 37s on it. I was getting ready to make the appointment for a regear when I read a post about the Pedal Monster. I figured it was only $300 so why not try it. I was shock at the difference it made. Needless to say, I stuck with the 4.10s..

 

[Wheelin98TJ]

Either way the 4:88 was the right choice for the 8 speed and 37s. restored back to factory shift patterns and on road RPM. The shop that I took this to was just doing the install as I was buying the gears elsewhere so it did not matter to them. Just took the advice of this jeep shop that does 2 -3 regears a week.

There is no right choice. It's subjective.

 

[Badweather]

I have a installed Pedal Commander which I believe would have similar results as the Banks unit

 

[human29]

I have a installed Pedal Commander which I believe would have similar results as the Banks unit

If you have the money the regear was the best money I spent. Made the jeep drivable again, night and day difference in my book.

 

[ttn333]

If you have the money the regear was the best money I spent. Made the jeep drivable again, night and day difference in my book.

I see this often. It wasn't my experience. It was absolutely drivable with stock 4.10. I did so for a couple of years with bumper/winch, rack/rtt. It was pulling a 2000lb (loaded) trailer up the mountain that forced the regear. I do feel that it does daily drive better with the 5.13.

 

[jwilson2899]

5.13 is a bit crazy to me, especially with a 8 speed. If we were all still stuck with 4,5, and 6 speed autos or manual it would make more sense to me. I'd say as long as you fall in a colored square, mechanically your fine. Its just to personally preference as to what's your taste.

Generic list - 65mph at 1:1 trans gear.

Thanks PuddleJumper the color coding really makes it clear

That chart is totally incorrect for a JL/JT with the 8 speed auto. Here’s the right one for our trucks:

I just did 5.13’s on mine with 37’s and I’m very happy. I’m turning about 2250 RPM with mine at 72-74 MPH. Fuel mileage is still good, 18-19, which is about what I was getting with the 4.10’s. The power, especially when taking off, is way better.

 

[dayusmc]

If everything else that I want to do to my jeeps was done, I would spend the money and regear to 4.88s even though my truck is doing fine with 4.10s on 37...

Unfortunately I keep finding new stuff to speed money on with my jeeps...

I will say this, if I didn't have the Banks Pedal Monster, I would have already regeared to 4.88...

 

[Pismo61]

Id go one step lower than you think you will need from my experience rear gearing 3 or so times.If you think you need 4.88s then go 5.13s.

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