Going from 35/12.5/20 to 37/11.5/20. Thoughts?

[tchur1]

I know on the older trucks with the 3.42 it was recommended to regear when going to a 37" tire. What's everyone take on having to do this on the 19+ trucks with a 3.73 rear end? Curious if the 37s will cause any transmission issues over an extended period of time (100k+ miles).

I cant speak to trans reliability because I only have 17k miles on my truck right now but I noticed very little difference in daily driving after putting on 37s. Granted I drive pretty slowly and rarely really hammer it from a stop. I think if you ask this to 100 people you're going to get 99 different answers.

 

[elephantrider]

it's best to regear and move the leverage back to the rear axle. I've not had any issues, but you can tell the 37's add some weight resistance, coming from 35's.

 

[Speedracer93CobraR]

Just a note regarding weight of the 2 different sizes. I was interested in the difference with the 37's being a little narrower. Nitto's site says this regarding the Ridge Grapplers:
35/12.5/20 - 70.5 lbs.
37/11.5/20 - 72 lbs.

The weight difference is very small which is interesting.

 

[Speedracer93CobraR]

I know you are keeping the stocks, but a +18 offset and 12.5's pull you out ever so slightly and get you a bit more manageable stance to fit the truck's overall size.
37's work so well on these trucks, it's just phenomenal....considering how hard 35's are to fit on the GMs.
These are my 37x12.50R18's Falken's on Racelines 18x9's +18.
View attachment 57691


View attachment 57689



View attachment 57690

That's a beautiful truck.

 

[Enve46]

Just a note regarding weight of the 2 different sizes. I was interested in the difference with the 37's being a little narrower. Nitto's site says this regarding the Ridge Grapplers:
35/12.5/20 - 70.5 lbs.
37/11.5/20 - 72 lbs.

The weight difference is very small which is interesting.

Recon Grappler which I have at 75lbs for 37x12.50s. You can feel them but they look and ride amazing. I did drop from 20s t0 17s

 

[DIRTRIDER]

I have 35 x 11.50 Falkens on stock wheels with 1.75 level.

 

[Speedracer93CobraR]

UPDATE: I did it.

I went from the 35/12.5/20 Nitto Ridge Grapplers to 37/11.5/20's. I would like a better picture, but this is all I have for now just after getting them installed.

I only have a level kit in the front.

Cons:

• Rub - I do have some rub at 'full lock'*
  • I already had some with the 35/12.5's so the difference is not much
• They look a little narrower than I would like, but that is purely aesthetic and a personal preference. The width difference is less noticeable if you are not looking at a side by side comparison of the 2 tires on the truck. When we put one on for test fit; you could see the difference while there was one of each size mounted on the front. Once all 4 were mounted; it's far less noticeable

Pros:

• The truck rides a little better. It's less harsh and rides smoother.
• RPM's dropped a small amount at highway speed and there seems to be a little difference in feel due to reduced rolling resistance of the larger diameter, but narrower tire.
• Fuel Mileage has increased some. I just installed the AEV Pro Cal Snap this morning so I will see what the computer shows over the next week, BUT I can confirm there is an increase in fuel mileage.

Overall:
As long as they wear over time like I expect, I would recommend this size. I look forward to driving in some gravel, mud, and snow when hunting season gets here.

 

[Speedracer93CobraR]

Just for reference, here is a side by side comparison of a Yokohama Geolander 35/12.5/20 and the Nitto Ridge Grappler 37/11.5/20 not mounted yet. It makes the 37's look really tall. I should have measured the Yokohamas to see if they 'run small'

 

[Joe_Lee]

UPDATE: I did it.

I went from the 35/12.5/20 Nitto Ridge Grapplers to 37/11.5/20's. I would like a better picture, but this is all I have for now just after getting them installed.

I only have a level kit in the front.

Cons:

• Rub - I do have some rub at 'full lock'*
  • I already had some with the 35/12.5's so the difference is not much
• They look a little narrower than I would like, but that is purely aesthetic and a personal preference. The width difference is less noticeable if you are not looking at a side by side comparison of the 2 tires on the truck. When we put one on for test fit; you could see the difference while there was one of each size mounted on the front. Once all 4 were mounted; it's far less noticeable

Pros:

• The truck rides a little better. It's less harsh and rides smoother.
• RPM's dropped a small amount at highway speed and there seems to be a little difference in feel due to reduced rolling resistance of the larger diameter, but narrower tire.
• Fuel Mileage has increased some. I just installed the AEV Pro Cal Snap this morning so I will see what the computer shows over the next week, BUT I can confirm there is an increase in fuel mileage.

Overall:
As long as they wear over time like I expect, I would recommend this size. I look forward to driving in some gravel, mud, and snow when hunting season gets here.

View attachment 58067

Looks great! Do you have rear factory air? What level kit?

 

[Rockcrawlindude]

Very nice. I want the 37x11.50 nittos

 

[Speedracer93CobraR]

Looks great! Do you have rear factory air? What level kit?

I don't have factory air, but I added an Airlift kit with the wireless setup in the rear.

I ended up using a basic Rough Country 2.5" level kit in the front. Kit is hardly accurate as it's just a spacer. I have not had any issues with it and didn't notice a change in ride from the factory setup. I put the level on immediately after buying the truck.

 

[phatboy64]

So for what it is worth. I just replaced my stock firestones on my 2023 3500 Limited HO with 37x12.5x20 Falken Wildpeek AT3 on Fuel wheels with +20 offset. Zero trimming… I also don‘t notice any lack of performance, seems just as quick off the line as the stock size tires. Not sure if it being an HO is making a difference but I wouldn’t even consider re-gearing. I took it up to 85 mph and smooth as glass….. As others have said, these trucks were meant to have 37s on them.

 

[BadKarma]

UPDATE: I did it.

I went from the 35/12.5/20 Nitto Ridge Grapplers to 37/11.5/20's. I would like a better picture, but this is all I have for now just after getting them installed.

I only have a level kit in the front.

Cons:

• Rub - I do have some rub at 'full lock'*
  • I already had some with the 35/12.5's so the difference is not much
• They look a little narrower than I would like, but that is purely aesthetic and a personal preference. The width difference is less noticeable if you are not looking at a side by side comparison of the 2 tires on the truck. When we put one on for test fit; you could see the difference while there was one of each size mounted on the front. Once all 4 were mounted; it's far less noticeable

Pros:

• The truck rides a little better. It's less harsh and rides smoother.
• RPM's dropped a small amount at highway speed and there seems to be a little difference in feel due to reduced rolling resistance of the larger diameter, but narrower tire.
• Fuel Mileage has increased some. I just installed the AEV Pro Cal Snap this morning so I will see what the computer shows over the next week, BUT I can confirm there is an increase in fuel mileage.

Overall:
As long as they wear over time like I expect, I would recommend this size. I look forward to driving in some gravel, mud, and snow when hunting season gets here.

View attachment 58067

Any updates? How’s everything? Was just quoted $2.5 for 5 installed next week. Any concerns with it being load range D?

 

[Speedracer93CobraR]

Any updates? How’s everything? Was just quoted $2.5 for 5 installed next week. Any concerns with it being load range D?

A few things:
1. These tires are made in the USA which I like. There are not many still made here.
2. Mine are load range 'E'. Did the place you are looking to buy from tell you something different?
3. I'm averaging about 1 mpg better in town, maybe more. That's not a lot, but I look at it as 25 more miles per tank. I'm seeing better on the highway, but I really have not been out on a run of enough length to give you good numbers. The main thing to me is that I did not lose. The fact I am seeing an increase is just a bonus.
4. The heaviest thing I have pulled since installing the tires is a boat and did not notice anything different in terms of power.
5. I am looking forward to getting out into the duck fields this year. These tires really roll over objects easier with the increased diameter and I think the decrease width plays a factor. I think they will get through the muddy field roads, gravel, and rock really well.

 

[Wanderlust073]

I cant speak to trans reliability because I only have 17k miles on my truck right now but I noticed very little difference in daily driving after putting on 37s. Granted I drive pretty slowly and rarely really hammer it from a stop. I think if you ask this to 100 people you're going to get 99 different answers.

Same. If you aren't towing heavy with it, why regear. If you are towing heavy with it, why did you put 37s on... If a truck that can pull 15,000 pounds can't handle an extra 20 pounds in rubber something's wrong.

Biggest difference I noticed is braking. I leave even more room than usual.

 

[BadKarma]

A few things:
1. These tires are made in the USA which I like. There are not many still made here.
2. Mine are load range 'E'. Did the place you are looking to buy from tell you something different?
3. I'm averaging about 1 mpg better in town, maybe more. That's not a lot, but I look at it as 25 more miles per tank. I'm seeing better on the highway, but I really have not been out on a run of enough length to give you good numbers. The main thing to me is that I did not lose. The fact I am seeing an increase is just a bonus.
4. The heaviest thing I have pulled since installing the tires is a boat and did not notice anything different in terms of power.
5. I am looking forward to getting out into the duck fields this year. These tires really roll over objects easier with the increased diameter and I think the decrease width plays a factor. I think they will get through the muddy field roads, gravel, and rock really well.
View attachment 58953
View attachment 58952

I am getting the 37/11.5/17’s from what I looked was load range d but yes they also told me. I thought about getting them for my OEM 20” but pulled the trigger on some method 315’s. Thank you for the insight! I primarily use my truck for DD and hunting during the fall/winter with occasional trails in Sedona or flagstaff.

 

[DesertRacer]

Same. If you aren't towing heavy with it, why regear. If you are towing heavy with it, why did you put 37s on... If a truck that can pull 15,000 pounds can't handle an extra 20 pounds in rubber something's wrong.

Biggest difference I noticed is braking. I leave even more room than usual.

I tow decently heavy and run 37s and it hasn’t been an issue. I cruise in 5th gear and run 4th gear for grades now instead of 6th and 5th stock, but I’ve been able to pull long grades at 70 without losing speed towing my fifth wheel that’s typically 12-15K lbs. I can feel a small loss in power compared to the stock 33s but it doesn’t bother me much, I’m not in a hurry when towing.

I do have a 2022 Cummins HO, an SO may feel it more. The deep first gear in the Aisin really helps get things moving off the line.