Gears for 37" tires

[PuddleJumper]

This dude doing 5.13s on 33s

I cruise at 75 all day long in 8th gear at less than 1800 rpm. I’m on 37s with 3.73s. Enjoy your 3000rpm cruising

So your saying the real solution is to just double the torque output. Who'd of thunk it?! Reasons I'm hemi swapping lol. Cus, the 3.6 ain't gonna hold longterm towing 5000lbs with 37s. No matter how deep you gear it.

Sponsored

 

[Wheelin98TJ]

I have a 22 JTOD 37s and 3.73s, also have a 24 JLU Willys gas with 37s and 4.10s, traded the 18 JLU sport with 35s on 3.42s or whatever that highway gear was. I wouldn’t regear any of them.

So your diesel can run at lower RPM than a gasser? No way!

 

[Camaroboi13]

So your diesel can run at lower RPM than a gasser? No way!

Apparently so can my JLU Willys and my 18 Sport with the same engine everyone is crying about here, imagine that!

 

[Wheelin98TJ]

Apparently so can my JLU Willys and my 18 Sport with the same engine everyone is crying about here, imagine that!

Those JLs weigh less. And gearing is subjective.

 

[Camaroboi13]

Those JLs weigh less. And gearing is subjective.

Excuses, sounds great. I’ve heard em all and it’s been debated to death. All I can do is just laugh.

 

[Wheelin98TJ]

Excuses, sounds great. I’ve heard em all and it’s been debated to death. All I can do is just laugh.

You're using a diesel as one of your "excuses" for being able to run 3.73 gears with 37s.

 

[Camaroboi13]

You're using a diesel as one of your "excuses" for being able to run 3.73 gears with 37s.

If it were gas I would have no complaints either, but who the hell wants gas when there’s diesel?

 

[Gladiator85]

Good for you glad you've found a 3.6 that can hold 8th with wimpy 3.73 mall crawler gears on 37s you have a unicorn . I have almost 150 miles on my 5.13s and I've had it up to 60 for a brief moment and was only doing 2k RPM. At 75 I'll be 2580 which is perfect as the 3.6 makes peak torque around 2500. Been babying it and it feels like a rocket from a dead stop. Gas mileage went from 15.5 to 17.3.

 

[Gladiator85]

This dude doing 5.13s on 33s

I cruise at 75 all day long in 8th gear at less than 1800 rpm. I’m on 37s with 3.73s. Enjoy your 3000rpm cruising

Yea running 75mph hanging the rings out the tail pipe. .

 

[mgw750]

If it were gas I would have no complaints either, but who the hell wants gas when there’s diesel?

I would guess a lot of people since they dropped the diesel.

 

[Zachanadandy]

Good for you glad you've found a 3.6 that can hold 8th with wimpy 3.73 mall crawler gears on 37s you have a unicorn . I have almost 150 miles on my 5.13s and I've had it up to 60 for a brief moment and was only doing 2k RPM. At 75 I'll be 2580 which is perfect as the 3.6 makes peak torque around 2500. Been babying it and it feels like a rocket from a dead stop. Gas mileage went from 15.5 to 17.3.

What if I told you the entire point of a double overdrive transmission is not to drive around at peak torque or more rpms than you need for the load? Downhill with a tailwind at 80mph, you're still pushing close to 3k and peak torque for almost no load.

 

[Gladiator85]

You might be right but 8th gear didn't exist unless on flat surface no wind. Why have an 8sp with those results? Have all the power in the world now plus get 1.5 to 2 mpg better. That's a win win if you ask me. Less strain on the drivetrain at highway speeds as well.

 

[Zachanadandy]

You might be right but 8th gear didn't exist unless on flat surface no wind. Why have an 8sp with those results? Have all the power in the world now plus get 1.5 to 2 mpg better. That's a win win if you ask me. Less strain on the drivetrain at highway speeds as well.

The drivetrain strain is a myth. The drivetrain sees the exact same load in 7th gear with 4.10s as 8th gear with 5.13s. Final drive ratio is all that matters. Unless you feel like you don't have a low enough 1st gear. Then you need gears. Why have an 8 speed trans that is in 8th at any speed over 40mph? I'd rather see 8th under low loads only than see 8th by half the speed limit. Not saying 5.13s is way too much for 37s, but is prefer 4.88s for that tire size. But 5.13s for 33s? That's as bad as the JL guys running 3.45s and 37s. Thanks to the 8 speed the gearing sweet spot is huge compared to previous autos, but there is still a too high and a too low in the extremes.

 

[Gladiator85]

All I know is hunting between 7th and 8th all day my mileage would drop off which tells me I'm working my vehicle harder. Worst thing you can do to a motor is lug it. 3.6 makes very little power below 2k. 5.13s were the best mistake I've ever made. Pulls up hills with ease in 8th. Consistent RPM is much better on the highway in the long run.

 

[Zachanadandy]

All I know is hunting between 7th and 8th all day my mileage would drop off which tells me I'm working my vehicle harder. Worst thing you can do to a motor is lug it. 3.6 makes very little power below 2k. 5.13s were the best mistake I've ever made. Pulls up hills with ease in 8th. Consistent RPM is much better on the highway in the long run.

Unless you drive around in manual mode, there's no way to lug the engine. The auto shifts based on load. Idling, even if it's down a steep grade at 100mph, is not lugging as there's no load. The 2nd you put any load on it, it downshifts automatically. No JL or JT is designed to "pull hills in 8th". 7th is still overdrive. That's an obvious sign it's over geared. If you like it over geared that's great. But it's over geared. At 85mph (80mph speed limits) you're at 3k rpms even downhill. Why? If you drive western freeway speeds you'll see a drop in fuel economy being over geared. Going from 4.10s to 5.38s on 38s led to a drop of 2mpg on road trips. Proving that over gearing exists.

Sponsored