3.73 gearing with 37s

[j.o.y.ride]

So I have been reading this and other threads, and have the desire to upgrade/mod my jeep to possibly a 33 tire size, maybe larger.
My question is this:
If I went to a 33 tire, would I need to regear?
I have no desire to do serious off-roading, but may enjoy an easy trail some time.
For me, I just enjoy the looks of a larger tire filling out the wheel well, and may or may not desire to add a lift at some point, but for now, just want to have the larger tire.

I appreciate any input and or opinions.

Definitely not worth it to re-gear on 33's. 3.73 will be fine and 4.10 no issue at all.

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[Deleted member 28696]

Okay everyone, I've scanned a lot trying to gather information on this topic from various places on the forum. I want to just hear from people with experience running 37s with 3.73 gearing on their JT, including their perception of their performance, how long they've been running that setup, and if they made any other mods. Thanks!

I have a JTR & for 37” tires I will be regearing from 4.10s to 5.13s which was recommended by Trail Jeeps who’s is installing my lift.

 

[RCKLNDR]

I drove on 37s with 3.73s in a heavy JKU for 2.5 years and didn’t even die. Even towed a 2700# camper. No, it wasn’t ideal, yes 5.13s were better, but it wasn’t unbearable. I have no qualms from running 35s w/ 3.73 paired up with the 8 speed thus far. I prefer trial and error over taking internet’s advice as gospel.

 

[wrpoole]

i have been looking at a couple jeep jt groups on facebook and have been lerking around here some. I must saw my jeep must be a unicorn. i have 37's on 3.73 gear and get 18.7 mpg. that is with 2 trips of over 200 miles to verify my claim.

People you need to learn to drive. these are not sports cars. light on the throttle and learn how to coast down hill.

Yes when i go offroad and beat the jeep up it drops to 14mpg but that smiles per gallon who cares.

Yes i have a tazer and have change the computer to the right tire sizing.

 

[Deleted member 28696]

I have 4.88’s on my 37’s and so far, it’s perfect imo.

If i was frequently using my truck to tow a camper id probably go 5.13; but ive talked to another member here extensively about his towing and he likes his 4.88.

It’s my understanding that 4.88s will take you back to stock specs for 37’s. For extra assurance my Jeep shop regears one step higher than stock to 5.13s. I’m going to be running 37s with 20” rims & with the extra weight of the rims 5.13s will probably be better to get those wheels going. I’m having a 3” lift put in as well. Most likely I will need a heavy duty steering box in the near future.

 

[StingyJT]

i have been looking at a couple jeep jt groups on facebook and have been lerking around here some. I must saw my jeep must be a unicorn. i have 37's on 3.73 gear and get 18.7 mpg. that is with 2 trips of over 200 miles to verify my claim.

People you need to learn to drive. these are not sports cars. light on the throttle and learn how to coast down hill.

Yes when i go offroad and beat the jeep up it drops to 14mpg but that smiles per gallon who cares.

Yes i have a tazer and have change the computer to the right tire sizing.

Good feedback and glad it’s working out for you! Just apples and oranges from Florida to Idaho or higher elevation - I have experience with both. If my JT were still in TX, I’d be on stock 4.10s with 37s. Being in Utah now, I regeared to 5.13s.

Naturally aspirated engines lose ~3% for every 1k feet, and that doesn’t factor in actually climbing grades.

 

[KurtP]

It’s my understanding that 4.88s will take you back to stock specs for 37’s. For extra assurance my Jeep shop regears one step higher than stock to 5.13s. I’m going to be running 37s with 20” rims & with the extra weight of the rims 5.13s will probably be better to get those wheels going. I’m having a 3” lift put in as well. Most likely I will need a heavy duty steering box in the near future.

4.56 puts you back at stock. 4.88 is one step, 5.13 is two. You wont be unhappy with 5.13.

 

[StingyJT]

4.56 puts you back at stock. 4.88 is one step, 5.13 is two. You wont be unhappy with 5.13.

Amen. Forgot to mention that Sport or Overland models will have better results compared to the Rubicon or Mojave, which weigh 400lbs more out of the box

 

[Deleted member 28696]

4.56 puts you back at stock. 4.88 is one step, 5.13 is two. You wont be unhappy with 5.13.

My Gladiator is a Rubicon they have 4.10s now, I'm also in Colorado so they may gear differently for the high altitude.

 

[KurtP]

My Gladiator is a Rubicon they have 4.10s now, I'm also in Colorado so they may gear differently for the high altitude.

If i lived there i would have gone deeper than 4.88 most likely. I think 5.13 is the right call for you.

 

[KurtP]

Amen. Forgot to mention that Sport or Overland models will have better results compared to the Rubicon or Mojave, which weigh 400lbs more out of the box

Id be curious to have a sport and a rubicon with same lift and tires and wheels on the same scale.... i think wheel and tire makes up most of that difference.

 

[DocMike]

I have 3.73 at 6,100 feet. I adjusted with a tazer, added a rubicon suspension for $200 and added JKS quick disconnects.

I may eventually go to 35s, but I am very happy with the current ride height. See before and after.

 

[cannonFodder]

When I was on 40x13.50s and 3:73's, it wasn't that bad at all. I don't do much highway driving, and I live in a relatively flat state (Florida) but I was getting 16ish mpg and was fine merging onto the highway and maintaining 70ish mph.

I don't take it off road and am now on 5:13s, for full disclosure.

The people that scream about it being a massive issue generally either live in an area where they are commuting extensively, taking it wheeling more than semi-casual and/or have some steep hills to climb.

 

[StingyJT]

Id be curious to have a sport and a rubicon with same lift and tires and wheels on the same scale.... i think wheel and tire makes up most of that difference.

I don’t think so but it’d be closer. Without other mods besides lift and tires, Rubicon will have the steel rear bumper, sliders on side and rear, and sway bar disconnect motor.

 

[glassjawkid32]

i have been looking at a couple jeep jt groups on facebook and have been lerking around here some. I must saw my jeep must be a unicorn. i have 37's on 3.73 gear and get 18.7 mpg. that is with 2 trips of over 200 miles to verify my claim.

People you need to learn to drive. these are not sports cars. light on the throttle and learn how to coast down hill.

Yes when i go offroad and beat the jeep up it drops to 14mpg but that smiles per gallon who cares.

Yes i have a tazer and have change the computer to the right tire sizing.

Which lift/suspension do you have here? Any rubbing?

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