Gearing Question

[C0ach78]

Newbie here, forum has a ton of great info.

I just bought a left over 2023 1500 Bighorn. It has 3.21 gears in it right now. I put a small lift on it and 35" tires (Milestar Patagonias). Now I understand I am not going to get great mileage with this thing, but I am wondering if I need to have different gears put in it? I just towed a small snowmobile trailer (12' enclosed with 2 snowmobiles in it probably weighs about 3500 lbs) about 160 miles and was averaging about 8 MPG on the trip and the truck never got into 8th gear. It mostly ran in 5th and 6th every great once in a while I could hit 7th on a slight downhill. Would it be wise to go to a different gear ratio in this? Maybe 3.92s or something?

 

[Redz72]

I bought my truck with 3.92’s knowing I was going to lift my rig and run 35’s. I am very satisfied with that decision and would do it again. However, after reading many many posts on 3.21vs3.92, I’ve come to realize it’s totally a personal preference. As the 3.21’s can be run with 35’s but get tradeoffs. And trade offs come with the 3.92’s as well. Do some research and you’ll see both sides of the coin. IMO, you’ll be fine with the 3.21’s and towing occasionally. The cost to upgrade gears isn’t worth the gains. But do your research and get lost in the banter

 

[kzielu]

For reference, my truck with 3.21 towing 3700lb car on 2000 lb open trailer gets average 13.5 mpg at 70mph (and sometimes almost 15 with favorable wind). Unless your snowmobiles were sitting really high on the trailer and creating drag, something is off. If you're using tow mode, it'll never go into 8th gear (for a good reason).

 

[HSKR R/T]

Newbie here, forum has a ton of great info.

I just bought a left over 2023 1500 Bighorn. It has 3.21 gears in it right now. I put a small lift on it and 35" tires (Milestar Patagonias). Now I understand I am not going to get great mileage with this thing, but I am wondering if I need to have different gears put in it? I just towed a small snowmobile trailer (12' enclosed with 2 snowmobiles in it probably weighs about 3500 lbs) about 160 miles and was averaging about 8 MPG on the trip and the truck never got into 8th gear. It mostly ran in 5th and 6th every great once in a while I could hit 7th on a slight downhill. Would it be wise to go to a different gear ratio in this? Maybe 3.92s or something?

Rehearing isnt really a viable option. You have to replace the entire front axle, you can't just swap the gear set

 

[C0ach78]

Rehearing isnt really a viable option. You have to replace the entire front axle, you can't just swap the gear set

Why can’t the gear set be swapped?

 

[C0ach78]

For reference, my truck with 3.21 towing 3700lb car on 2000 lb open trailer gets average 13.5 mpg at 70mph (and sometimes almost 15 with favorable wind). Unless your snowmobiles were sitting really high on the trailer and creating drag, something is off. If you're using tow mode, it'll never go into 8th gear (for a good reason).

They were in an enclosed trailer. It is a flat front trailer so there is drag for sure. Maybe that and my taller tires could bring me that much lower than you?

 

[Rick3478]

Lift with tall tires vs. towing are working at cross purposes, not just because of gearing but stability is also reduced. Would you hate me if I said back off to 33's and hope to be able to hold 6th gear?

 

[HSKR R/T]

Why can’t the gear set be swapped?

The front gear set is not serviceable. It's welded into the carrier. Have to swap while axle assembly

 

[kzielu]

They were in an enclosed trailer. It is a flat front trailer so there is drag for sure. Maybe that and my taller tires could bring me that much lower than you?

With enclosed it makes sense - it's the frontal area and drag, weight in this case is secondary from mpg point of view.

 

[bigjeffg]

Newbie here, forum has a ton of great info.

I just bought a left over 2023 1500 Bighorn. It has 3.21 gears in it right now. I put a small lift on it and 35" tires (Milestar Patagonias). Now I understand I am not going to get great mileage with this thing, but I am wondering if I need to have different gears put in it? I just towed a small snowmobile trailer (12' enclosed with 2 snowmobiles in it probably weighs about 3500 lbs) about 160 miles and was averaging about 8 MPG on the trip and the truck never got into 8th gear. It mostly ran in 5th and 6th every great once in a while I could hit 7th on a slight downhill. Would it be wise to go to a different gear ratio in this? Maybe 3.92s or something?

Is your truck 4X2 or 4X4? This will really change the formula on how hard and expensive changing gears to 3.92 will be.

If 4X2 most shops can change gears. You will want to update your computer for both wheel size and gearing. Lots of options for this.

If you are 4X4 this complicates the situation. Ram doesn’t give us a good path to easily change gearing. The AAM 8.25 front axle doesn’t allow you to change gears. You need to replace the entire carrier to change gearing. This really complicates the process, and the cost.

A good write up on wether the juice is worth the squeeze: An Engineer's Ultimate Guide To 3.21 VS 3.92 Axle Ratio

 

[Casull]

Putting normal size tires on would be easier than changing gears.

 

[bigjeffg]

I’m a big off road guy, so 35” tires are a must for me. I already have 3.92 with my Rebel package. It would be worth it to me, but it’s a $$$$ load of money for just having a better looking truck.

 

[nc_beagle]

Doesn't affect your decision but I do go into 8th gear at times while pulling a 5500ish pound Travel Trailer. Using Tow/Haul mode.

Diesel with 3.92