What's new
By:
Ram Heavy Duty Forum

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Gearing and larger tires

S

spinned

Member
Messages
79
Reaction score
74
Points
18
I have been exploring replacing the factory tires with 35s or 37s on my soon to be 2022 2500. I’m amazed at the lack of discussion on regearing for the HD trucks. Coming from a wrangler the regear is standard practice… but even the Mopar sanctioned Rocky Ridge lift/37” tire package did not mention regearing. Is it because the Cummins engine has so much torque to compensate for the tire size… or is everyone just accepting the lower level of power that taller tires introduce just to get the good looks? I like the big tires but also like the OEM power and torque. What is the scoop on regearing for 35s and 37s?
 
I am also going from the Wrangler to the 3500. Wrangler is still in the garage. We had this discussion when the Ecodiesel was released in 2020. The Rubicon Dana 44 rear axle ratio was changed to 3.73 instead of the traditional 4.10's. The answer was the torque. It's still that way today.

Regarding the Ram trucks, the cost for a 4.10 from factory is $145 bucks. Can't beat that. A regear has to be 2k or more. So short answer is get the 4.10 axle ratio from the factory, add 37's and you end up with a mathematically similar ratio to the 3.73
 
Overland.Productions said:
I am also going from the Wrangler to the 3500. Wrangler is still in the garage. We had this discussion when the Ecodiesel was released in 2020. The Rubicon Dana 44 rear axle ratio was changed to 3.73 instead of the traditional 4.10's. The answer was the torque. It's still that way today.

Regarding the Ram trucks, the cost for a 4.10 from factory is $145 bucks. Can't beat that. A regear has to be 2k or more. So short answer is get the 4.10 axle ratio from the factory, add 37's and you end up with a mathematically similar ratio to the 3.73
Click to expand...
Wont get 4.10s in a diesel unless its a dually
 
Overland.Productions said:
Regarding the Ram trucks, the cost for a 4.10 from factory is $145 bucks. Can't beat that. A regear has to be 2k or more. So short answer is get the 4.10 axle ratio from the factory, add 37's and you end up with a mathematically similar ratio to the 3.73
Click to expand...

Sweet! My new gasser should be all set then if I decide to go that route. Thanks for the info.
 
From a similar post off Facebook:

If you want to save your transmission, 100% yes on regearing.

Most these knuckle heads think because their truck makes a ton of torque and they don't notice a loss in performance with the larger tires that things are all sunshine and rainbows.
And then you grenade a transmission that cost you 8k to fix properly. This is why every one says the 68 is "trash".
 
I have an appointment to get 4.10`s installed in 2 weeks and will report back. The gear set in parts is $1100.00 CDN. I want to move the leverage and be in boost more when going up long steep hills that are everywhere in my area. I hesitated pulling the trigger on them but they are AAM and it is the right way to do it. I will let everyone know on here if I regret doing it, if I think I should have done it sooner or if they grenade my axles first pull coming out of the shop.
 
I’ve got a CCLB on order with Hemi, 4.10, and 50 gallon tank. I know it will be fine with 35s, but wondering how it would behave with 37s?


Sent from my iPhone using Tapatalk
 
spinned said:
From a similar post off Facebook:

If you want to save your transmission, 100% yes on regearing.

Most these knuckle heads think because their truck makes a ton of torque and they don't notice a loss in performance with the larger tires that things are all sunshine and rainbows.
And then you grenade a transmission that cost you 8k to fix properly. This is why every one says the 68 is "trash".
Click to expand...

Exactly.

And don't believe the folks telling you "I can't notice a difference in acceleration when I put 35's on mah Cummins monster beast diesel!!" Sure you will notice the power loss less than a gas engine with half the torque, but you DO notice.

I put 35's on my 2016 2500 cummins truck and it was absolutely noticeable. Not enough to go back to stock, but I felt it indeed.

New truck was ordered with 4.10's from factory so I'll be ready when I finally get around to a tire upgrade.
 
AEV_CUMMINS said:
I have an appointment to get 4.10`s installed in 2 weeks and will report back. The gear set in parts is $1100.00 CDN. I want to move the leverage and be in boost more when going up long steep hills that are everywhere in my area. I hesitated pulling the trigger on them but they are AAM and it is the right way to do it. I will let everyone know on here if I regret doing it, if I think I should have done it sooner or if they grenade my axles first pull coming out of the shop.
Click to expand...
Great… I’d love to hear additional objective comments. I agree that you would have to notice it. But that is from the viewpoint of increasing my tire size on a wrangler. It REALLY stretched out the gears. Of course the torque on the Cummins may partially mask that, but the the math on the gear ratios would be similar. I’d also like to hear from anyone who towed 7-10k on 35s vs stock without regearing. It has to be noticeable. Like I mentioned in a quote above, maybe some complaints on the 68 are because people didn’t regear after increasing tire size, as the increased tire size would put a lot more pressure on the tranny.
 
I've got 35s on a cummins 2500 and tow a 10k lb 5th wheel. For me there was no loss of power or drive ability. No need to regear from 3.73s.
 
Yea i dont agree with the need to regear personally, in my experience with my 01 3500 it came with 4.10s i put 35s on it and it still was to much gear when hauling i dropped it to 3.73 and was much happier and even now that i dropped it back to the 31s i wish i would have went to 3.55s
 
G’Dave said:
I’ve got a CCLB on order with Hemi, 4.10, and 50 gallon tank. I know it will be fine with 35s, but wondering how it would behave with 37s?


Sent from my iPhone using Tapatalk
Click to expand...
Not sure what you mean by "behave", but I don't have any negatives to report with that same combo. Of course I went to 37s before having a chance to drive around in stock form for too long. And with the 4.10s combined with the 8-speed I feel spoiled compared to my 4th gen with 3.73s and 6-speed.
 
LateToTheParty said:
Not sure what you mean by "behave", but I don't have any negatives to report with that same combo. Of course I went to 37s before having a chance to drive around in stock form for too long. And with the 4.10s combined with the 8-speed I feel spoiled compared to my 4th gen with 3.73s and 6-speed.
Click to expand...

I was referring to the truck’s ability to take off a normal speed (faster than a school bus lol) and also cruise at highway speeds in 8th gear. It sounds like it will be no dramas if I go with 37s.
Good feedback - thanks!


Sent from my iPhone using Tapatalk
 
spinned said:
Great… I’d love to hear additional objective comments. I agree that you would have to notice it. But that is from the viewpoint of increasing my tire size on a wrangler. It REALLY stretched out the gears. Of course the torque on the Cummins may partially mask that, but the the math on the gear ratios would be similar. I’d also like to hear from anyone who towed 7-10k on 35s vs stock without regearing. It has to be noticeable. Like I mentioned in a quote above, maybe some complaints on the 68 are because people didn’t regear after increasing tire size, as the increased tire size would put a lot more pressure on the tranny.
Click to expand...
Just pulled my 10k travel trailer with my 3500 HO Cummins on 37’s and it still pulls like it doesn’t care. I did this same towing with my 2020 2500 on 37’s, still pulled great. If I someday have to replace the Aisin, so be it.
 
Food for thought…..from 2013(or so) until 2018(iirc) the CTD’s only gear option (on the 2500 at least) was 3.42

With 3.73 gearing, going from a stock 33 to a 35 makes the effective ratio about 3.55ish which is still more mechanical advantage than than a stock 3.42 geared truck.

Jumping to 37’s drops you down to about to 3.35ish
 
You must log in or register to reply here.
Back
Top