2500 6.4 w/ 37 & 73s

[iPunch]

So I have been reading through the posts regarding tire size and how they affect effective gear ratio. The ram (2017 4x4) we bought came with 37x12.5x20 tires (3600 load capacity) with a 2" level kit. The problem is we have a 9600lb 32' TT that we are planning on pulling for a weekend or two less than 500 miles mostly flat (some foothills) round trip.

I understand the stress put on the transmission by doing this along with the stability loss due to sidewall flex isn't something that would make the current setup I have anywhere close to ideal for pulling a load.

The effective gear ratio that my truck has now is 3.31 or 3.37 i think. The two options I can come up with is either regearing both axles to 4.56 or buying some stock size tires to tow with. I just found a set of stock wheels with tires for $450 but they're 275/70/18's, but i think that would drastically change the looks of the truck.

Would changing my tire size to 35's be enough of a compromise to comfortably tow with or is that still going to be too much strain on the tranny for occasional towing?

 

[1500ram12]

Chances are you have 3.73's.

Pros of swapping to a 4.56 w/37's
May gain back some mpgs
Less strain on trans, axles
Some more I just can't think of

Cons
Cost

Pros of getting a set of used stock wheels and tires
Cost
Being able to return to stockish when selling
Less strain on drivetrain when towing

Cons
Looks goofy
Having to switch every time you tow

If I could afford the gear swap I'd go that route.


Sent from my iPhone using Tapatalk Pro

 

[Ratket]

Go to the heavy duty section...
Tons and tons of re gear posts in there specifically for your truck.
I can tell you right now, skip past 4:56 and go straight to 4:88, if 5:13”s- 5:30”s are available then go that route “ As long as you stay with a 37” tire or bigger”. The 6.4 with MDs and the 6 speed on a 35” tire with 4:56 or 4:88 is LOVED BY ALL who have made the switch. As long as your 37”s are a LT Tire or rated E you should be fine. But please check the HD section and look at all the Gear Threads- and make note of the guys who have done it and what they say.

https://www.ramforum.com/threads/6-4-hemi-4-56-gears-speed-and-rpms.109503/

https://www.ramforum.com/threads/6-4-hemi-gear-swap.77499/

https://www.ramforum.com/threads/finally-got-my-4-88s-installed.134016/

I could keep going but you get the point, fyi- don’t read while ur on the *******, your wife will send a search party after an hour....

 

[iPunch]

Thanks to both of y’all!

don’t read while ur on the *******, your wife will send a search party after an hour....

That’s easily what my wife hates about me the most

 

[GsRAM]

If you want to stick with the 37s I'd go to a 5.13 gear.

35s - 4.88s are good

Stock size tires (like mine) if I ever do it I'm going 4.56s.

Going from 3.73s to 4.10s or 4.30s (stock tire) is not enough of an improvement to warrant the 3k price of the job. (4x4 truck). If you spend the money to regear you want a seat of the pants improvement for that kind of coin. On stock tires I could feel no seat of the pants difference between my truck with 73s and another truck with 10s.

So if your gonna do it...do it right. I've yet to read a post by someone who regeared with a bigger gear complain, but I've read some who didn't go steep enough and regretted it.

Just my .02.

 

[Nick@GotExhaust]

Go with gears. it will be better all around for your driving. Also look into the Pulsar, then you can adjust speedo for tire size and bump up the power a little.

We offer Yukon gears, Red Line fluids and the Pulsar. Contact me if you would like a quote

 

[VernDiesel]

Go the cheap route for now soon the 8 speed will be available which is a dramatic improvement. Trade up. Still would love the 4.56 with 37 but honestly the 3.92 would work well with the 8 speed you just wouldn’t use the two overdrives. Maybe early as this summer? Food for thought.

 

[RoadRamblerNJ]

If you want to stick with the 37s I'd go to a 5.13 gear.

35s - 4.88s are good

Stock size tires (like mine) if I ever do it I'm going 4.56s.

Going from 3.73s to 4.10s or 4.30s (stock tire) is not enough of an improvement to warrant the 3k price of the job. (4x4 truck). If you spend the money to regear you want a seat of the pants improvement for that kind of coin. On stock tires I could feel no seat of the pants difference between my truck with 73s and another truck with 10s.

So if your gonna do it...do it right. I've yet to read a post by someone who regeared with a bigger gear complain, but I've read some who didn't go steep enough and regretted it.

Just my .02.

+1
Go big or go home. You will NOT regret it. 5.13s will just make you giggle out loud every time you hit it! LOL.

 

[RoadRamblerNJ]

So I have been reading through the posts regarding tire size and how they affect effective gear ratio. The ram (2017 4x4) we bought came with 37x12.5x20 tires (3600 load capacity) with a 2" level kit. The problem is we have a 9600lb 32' TT that we are planning on pulling for a weekend or two less than 500 miles mostly flat (some foothills) round trip.

I understand the stress put on the transmission by doing this along with the stability loss due to sidewall flex isn't something that would make the current setup I have anywhere close to ideal for pulling a load.

The effective gear ratio that my truck has now is 3.31 or 3.37 i think. The two options I can come up with is either regearing both axles to 4.56 or buying some stock size tires to tow with. I just found a set of stock wheels with tires for $450 but they're 275/70/18's, but i think that would drastically change the looks of the truck.

Would changing my tire size to 35's be enough of a compromise to comfortably tow with or is that still going to be too much strain on the tranny for occasional towing?

SouthTexan posted this calculator back in Sept, 2017. Invaluable for this kind of back & forth.

https://www.crawlpedia.com/rpm_gear_calculator.htm

 

[DarthMegaHD]

I’m gonna vote compromising with 35s. Cheapest and quickest way to go, and you won’t have to do a nascar pit stop just to tow. If it was an option, I’d say 35s and 4.56.

 

[RedneckHippy]

Go to the heavy duty section...
Tons and tons of re gear posts in there specifically for your truck.
I can tell you right now, skip past 4:56 and go straight to 4:88, if 5:13”s- 5:30”s are available then go that route “ As long as you stay with a 37” tire or bigger”. The 6.4 with MDs and the 6 speed on a 35” tire with 4:56 or 4:88 is LOVED BY ALL who have made the switch. As long as your 37”s are a LT Tire or rated E you should be fine. But please check the HD section and look at all the Gear Threads- and make note of the guys who have done it and what they say.

https://www.ramforum.com/threads/6-4-hemi-4-56-gears-speed-and-rpms.109503/

https://www.ramforum.com/threads/6-4-hemi-gear-swap.77499/

https://www.ramforum.com/threads/finally-got-my-4-88s-installed.134016/

I could keep going but you get the point, fyi- don’t read while ur on the *******, your wife will send a search party after an hour....

How did you know!?

 

[Ratket]

How did you know!?

We have all been there... when she sends her mom looking for me then it gets real! Lol

 

[68PowerWagon]

I went from 3.73's to 4.56 with stock tires. No regrets what so ever! Pulls my 13k+ 5th wheel much better. With this gearing the transmission shifts like it should (upshifts & downshifts). With bigger tires you will absolutely want to go with more than just 4.56. Somewhere in the 5's like mentioned above.