3.21 8speed and 37s

[Lifted2wd]

Also depends where in the US you live. If your down south, there are no hills and its all flat. Up north, you have long steep hills. I live in Pennsylvania, so i fight long steep hills daily.

View attachment 123213

I'm in Arizona. Flat as ****.

 

[MNEvan]

I've had my 37s on my 15 w/3.21 since Oct and had no power loss and love the ride. I don't really notice the gear hunt, and eco mode works perfect

I just got a 2017 and I have the 3.21 and really want to go with 37s but I’m worried about strain to the tranny. Also what you get fuel economy wise

 

[Maligator]

I just got a 2017 and I have the 3.21 and really want to go with 37s but I’m worried about strain to the tranny. Also what you get fuel economy wise

I just had a zone 6" kit and 37s on my 2017 with 3.21s. so far so good, I drive pretty conservative so I do my best to try and not cause unneeded strain on things. I just took a hilly trip from MD to upstate NY and I averaged 16.2 mpgs from driveway to driveway. I also opted to go with one of the lightest 37" tire I could find the BFG KM2 weighed in at 4 lbs heavier than my 295 70 r18 Nitto trail Graps I had. They are a D rated tire but I don't tow/haul nor do alot of off roading. On my trip I watched my tranny temps and they stated normal never went over 190. Right now she's a daily driver but won't be once my wife gets her second vehicle.

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[Lifted2wd]

I just got a 2017 and I have the 3.21 and really want to go with 37s but I’m worried about strain to the tranny. Also what you get fuel economy wise

I'm getting between 15-16mpg on the freeway on the 37's. I have also not recalibrated anything for correct MPH, so that could be off by a little.

 

[BTD07]

My truck is a 2010 so i dont have the 8-speed. I have 3:92 gears, 6" lift, and 37's. At a dead stop, when i stomp on it, the truck wont even spin the tires...at all. Truck is a pig with 37's and 3:92 gears. I only get 12 mpg on the highway. Passing people on the highway is possible, but takes forever. Only cure is a blower. I cant imagine running 3:21 gears and 37's. There isnt that much of a difference between the 6 speed and 8 speed when your going above 55mph.
If i had 3:21 I wouldnt even think about 37's.
Also depends where in the US you live. If your down south, there are no hills and its all flat. Up north, you have long steep hills. I live in Pennsylvania, so i fight long steep hills daily.

View attachment 123213

Its interesting because if a non truck person sees that, theyd think 'man theres nothing that truck cant conquer!' and youre here saying you fight to get up hills lol. Not poking fun, just somewhat ironic. Looks cool though!

 

[Lifted2wd]

Its interesting because if a non truck person sees that, theyd think 'man theres nothing that truck cant conquer!' and youre here saying you fight to get up hills lol. Not poking fun, just somewhat ironic. Looks cool though!

I love the "looks cool" feature of my truck now. I can spin the tires with the 3.21's, 37's are heavy for sure

 

[MNEvan]

I just had a zone 6" kit and 37s on my 2017 with 3.21s. so far so good, I drive pretty conservative so I do my best to try and not cause unneeded strain on things. I just took a hilly trip from MD to upstate NY and I averaged 16.2 mpgs from driveway to driveway. I also opted to go with one of the lightest 37" tire I could find the BFG KM2 weighed in at 4 lbs heavier than my 295 70 r18 Nitto trail Graps I had. They are a D rated tire but I don't tow/haul nor do alot of off roading. On my trip I watched my tranny temps and they stated normal never went over 190. Right now she's a daily driver but won't be once my wife gets her second vehicle.

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Do you have 4wd truck also how much did the lift and tires raise the truck?

 

[Maligator]

Do you have 4wd truck also how much did the lift and tires raise the truck?

Yup 4wd. I'm out of town right now and don't have a tape measure handy but it's pretty significant from stock. I would venture to guess from the ground to top of my Fender well it's probably roughly 46" or so. I also have my bills adjusted to 2.8" in the front with the 5" rear zone springs

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[MNEvan]

I have a 2016 Ram 1500 with a pro comp 6" lift and a 1.5" body lift. Wheels are 20x10 XDs and 37x12.5 MTs. Truck drives just fine man! Has no issues with the acceleration or lack of it with the 3.21 gears! I average 17mpg with a 50/50 mix of express way and around the town driving. Just did minor add ons like the peddle commander, ported throttle body, intake and cat back exhaust. Just go with it, I'm super pleased with the setup and have NO issues with running 37s and 3.21 gears.

Still running problem free?

 

[jhanes]

I have 2016 sport 3:21 8 speed 37” tires. It has good power but 8th gear rarely is used and fuel mileage isn’t great

 

[RedSRT4Me]

I'm in Arizona. Flat as ****.

You live in the west valley??

Head 30 minutes east or north and mountains are everywhere.

 

[Lifted2wd]

You live in the west valley??

Head 30 minutes east or north and mountains are everywhere.

I'm in Gilbert. LOL I take it up into the mountains all the time. But for out of towners or those that don't venture we are flat.