Gears for 37" tires

[FLUndertaker]

I’ve got nitto 37’s with 5.13 gears and get low 16 mpg according to the computer. I don’t care. Between the pedal commander, deep gears, and my fondness for the skinny pedal, mpg is one of the furthest things from my mind.

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[steve68]

I’ve got nitto 37’s with 5.13 gears and get low 16 mpg according to the computer. I don’t care. Between the pedal commander, deep gears, and my fondness for the skinny pedal, mpg is one of the furthest things from my mind.

raising a faux glass like a toast! Here! Here!

people used to ask when I had my 4Dr, what kind of gas mileage do you get, I used to tell them, if that’s something you have to ask, you don’t want one!!

 

[OngsterA]

Got 5.13s in April, drove 500 miles and changed the gear oil, then drove 4100 miles from NJ to CO and back the past 10 days. I towed a 2,350# 5x8 uhaul enclosed trailer without brakes and the JT weighed 6,920 w/3 passengers and full tank of gas. The trailer towed like it wasn't behind me except I could feel it when there was a strong crosswind or sometimes passing a semi. The braking distance was a little impacted but not by much. Refresher - I have JTR with 37s and 3in lift with accessories including RTT on 1/2 bed rack, 1/2 roof rack over cab, 270deg awning, winch, plus some other accessories.

Avg 10.8 mpg heading to CO and 11.7 coming back so that's a total trip average of 11.2 (hand calculated). Just over $1500 was my fuel bill ? and that was about $450 more than my fuel bill for the same trip in January (I didn't tow a trailer then and averaged 11.9mpg). Just like in January, I was driving an average of about 5 mph over the posted speed limit throughout the trip. I believe 2-3 mpg could be gained if I didn't exceed 65mph vs the 75-80mph I was pushing the brick.

Bottom line is I'm really happy with the 5.13s on both highway and off-road. Shop recommended the 5.13s over the 4.88s and they were right. I was also happy with being able to do 65mph going up the steep, long and high altitude CO passes without the engine close to redline but I can see why others that are consistently towing significantly more weight up the passes might want 5.38s, or better yet, simply a truck with more power. But for my situation and plans to not tow over 4k pounds, I am extremely happy with the Gladiator on 37s w/5.13s.

Good assessment, which brand gearset did you get? I’m starting to research all this.

 

[DocMike]

4.88 and 35s....Yeah I had a few choice comments for people with those questions...I got 16-17 on 35s with a RTT and a full bed of camping gear...4 kids and a dog. Drove all over AZ, UT and Colorado. Lots of climbing big stuff.
Plus hit a BOH trail loaded down. Not great, but can't do that in an outback.
For reference...Roam Vagabond XL, Rebel 1/2 rack. Full food, water, recovery, and camping gear for 5 people plus dog for 4 days. She was a bit of a piggy.

raising a faux glass like a toast! Here! Here!

people used to ask when I had my 4Dr, what kind of gas mileage do you get, I used to tell them, if that’s something you have to ask, you don’t want one!!

 

[OngsterA]

That depends on the speed and RPM that you're traveling at when you are attempting the pass. With my 5.13s, I have seen 4th for passing but I'm also at a lower speed. As I increase speed the vehicle can't downshift to 4th as it would essentially be right near redline so the truck won't go there. I live about 4.2k in elevation and travel to and from Moab and southern Utah and haven't had an issue passing. The only time I feel the truck lug is going up really steep grades into the canyons or over mountain passes.

I also have mountain passes here, one is almost constant 6 percent grade for 5 miles or so. I’m opting for 5.13s on 37 since doing some towing (track car) and crawling also. My question is, what about manual downshifts on the ZF, should work fine correct? I can select to hit the power band and avoid lugging and overrevs.

 

[Muddzy]

Good assessment, which brand gearset did you get? I’m starting to research all this.

Revolution. All of the other shops quoted Yukon IIRC. It's all metal to me so I just went with what the shop recommended and had experience installing the most.

 

[wanderer]

Ok you guys that are getting 17 mpg. How fast are You driving ? I usually am in the 70 75 mph range. I also have the mini tazer and reset my tire size so what or why would I get only 13.5 mpg ? I didn’t buy this to get good mileage. But I still want to know ?

 

[Pat2Alaska]

Ok you guys that are getting 17 mpg. How fast are You driving ? I usually am in the 70 75 mph range. I also have the mini tazer and reset my tire size so what or why would I get only 13.5 mpg ? I didn’t buy this to get good mileage. But I still want to know ?

65 is max for me. I get 17-18 from 60-65 under most conditions. Above that the MPG drops quickly.

 

[Jeeperjamie]

Ok you guys that are getting 17 mpg. How fast are You driving ? I usually am in the 70 75 mph range. I also have the mini tazer and reset my tire size so what or why would I get only 13.5 mpg ? I didn’t buy this to get good mileage. But I still want to know ?

 

[Jeeperjamie]

Ok you guys that are getting 17 mpg. How fast are You driving ? I usually am in the 70 75 mph range. I also have the mini tazer and reset my tire size so what or why would I get only 13.5 mpg ? I didn’t buy this to get good mileage. But I still want to know ?

Stubby bumper, snorkel, and the rack on the back are probably the main factors. I picked a full width bumper to help the air flow around my Jeep and not up into the fenders which causes lag. The snorkels not very aerodynamic and will cause lag and then add the weigh of the rack on the back equals crappy mpgs

 

[Muddzy]

Stubby bumper, snorkel, and the rack on the back are probably the main factors. I picked a full width bumper to help the air flow around my Jeep and not up into the fenders which causes lag. The snorkels not very aerodynamic and will cause lag and then add the weigh of the rack on the back equals crappy mpgs

Not to mention a Rubicon is heavier than some of the other models. Also, heavier wheels and tires make some difference. All of this, the RTT and the stuff you mention def increase wind resistance. I should know since I ride with a similar setup and get similar crappy mileage. I also drive 5-10mph over the speed limit which makes it exponentially worse.

 

[Barnaby’sdad]

65 is max for me. I get 17-18 from 60-65 under most conditions. Above that the MPG drops quickly.

Yup. The whole “aerodynamics of a brick” thing. Want better fuel economy? Slow down, for starters.

That example above. I bet that rack mounted tent is a MPG or two. I can see running that setup for a trip, but I wouldn’t be leaving that mounted up there permanently for the lol’s like a lot of the folks seem to do in my area.

 

[Orange01z28]

I just switched from 35x12.5 Toyo Open Country MTs to 37x12.5 Milestar Patagonia XTs and feel zero discernable difference whether in butt-in-seat performance or fuel mileage. In fact, my 37s are 2 lbs lighter per tire than the 35s were

Talk me off the ledge here. Do I really need to re-gear? Is it worth all that money in parts and labor? I figure I could sell the brand new, in-box gears fairly easily to recoup those costs, and just cancel my appointment

There is talk about us getting a boat, which I then know would require regearing for towing, but i seem to be ok in my current use case

 

[Muddzy]

I just switched from 35x12.5 Toyo Open Country MTs to 37x12.5 Milestar Patagonia XTs and feel zero discernable difference whether in butt-in-seat performance or fuel mileage. In fact, my 37s are 2 lbs lighter per tire than the 35s were

Talk me off the ledge here. Do I really need to re-gear? Is it worth all that money in parts and labor? I figure I could sell the brand new, in-box gears fairly easily to recoup those costs, and just cancel my appointment

There is talk about us getting a boat, which I then know would require regearing for towing, but i seem to be ok in my current use case

There is no ledge. If you're happy with the JT's performance without regearing then why regear? I towed a 3500lb boat with mine without regearing and it did good enough that I didn't feel the absolute NEED to regear. When I went overlanding in CO on steep grades at altitude then I knew I needed to regear.

 

[OngsterA]

I just switched from 35x12.5 Toyo Open Country MTs to 37x12.5 Milestar Patagonia XTs and feel zero discernable difference whether in butt-in-seat performance or fuel mileage. In fact, my 37s are 2 lbs lighter per tire than the 35s were

Talk me off the ledge here. Do I really need to re-gear? Is it worth all that money in parts and labor? I figure I could sell the brand new, in-box gears fairly easily to recoup those costs, and just cancel my appointment

There is talk about us getting a boat, which I then know would require regearing for towing, but i seem to be ok in my current use case

Keep in mind those Patagonias have soft tread and casing, why they're light, don't think they will last as long as other similar tires.

Re-gearing depends on needs, I think unless you crawl steep terrain you won't need it. Towing not sure how much it impacts, again depends on where you tow, hills or flat mostly.

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