Gear Change Req'd for 33's?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

BFeist

Junior Member
Joined
Feb 18, 2020
Posts
4
Reaction score
1
Location
OKLAHOMA CITY
Ram Year
2013
Engine
5.7L Hemi
Bought the truck used with 33x12.5x20's on it. I noticed it has trouble staying above 70 on the hwy without downshifting (5.7L, 8-spd tranny). Other than that, it runs and shifts just fine. Roughly 75K miles on it now. I do mostly city driving with the occasional few-hour hwy trip, and Its never towed anything yet, but I'll be eventually towing my wife's altima (military move). You guys recommend I get the gears changed out for this tire size increase before towing something significant? I plan on keeping it for years to come. Thanks!
 
OP
OP
B

BFeist

Junior Member
Joined
Feb 18, 2020
Posts
4
Reaction score
1
Location
OKLAHOMA CITY
Ram Year
2013
Engine
5.7L Hemi
I was thinking 33's were just a tad larger in diameter than the stock. If that's stock then I guess I'm good. No, theres no weird smells of any kind. The tires on there are Nitto MT's, that could also be a factor I guess. You have no issues cruising at hwy speeds without the overdrive kicking off? Yours an 8-speed?
 

Brandon-w

Senior Member
Joined
Jan 2, 2019
Posts
3,257
Reaction score
4,938
Location
Yukon
Ram Year
2015 Ram 1500
Engine
6.4
I think they're 1/4 inch bigger than stock but considering all things it's only1/8 Inch difference not enough to remotely notice at all. Yeah I have the 8 speed before it was tuned it would hunt around Alittle on the hills or in a bit if wind. The tires are considerably heavier than stock so maybe that has something to do with it. I think factory tires and wheels weigh in at about 80pounds and the ones you are running are probly closer to 110 each plus width adds rolling resistance. Still doesn't make sense why it seems to struggle though. I have a trans tune now and it made an amazing difference with the transmission it holds gears way better now.
 
OP
OP
B

BFeist

Junior Member
Joined
Feb 18, 2020
Posts
4
Reaction score
1
Location
OKLAHOMA CITY
Ram Year
2013
Engine
5.7L Hemi
I can attest to the increased weight lol. Im also only getting about 13-14 combined mpg. Again, mostly city driving but even on the highway I'm averaging like 15, going around 75mph. What was involved in the trans tune? May consider going that route. Thanks again for the help.
 

U&A

Senior Member
Joined
Apr 29, 2016
Posts
9,261
Reaction score
18,560
Location
Michigan
Ram Year
2016 3500 SRW
Engine
6.4 HEMI
Stock size is 33 as stated. Regardless of weather the tire is possibly a half inch taller ..... if your truck is struggling something else is wrong.

What are your stock gears?

My stock gears were not impressive with stock tire size (also 33’s) on my 6.4 hemi 3500. But a 1/2 tone should have NO problem getting out of its own way with just a wider tire. They have a lot of power for the size of the truck.




Sent while firmly grasping my redline lubed RAM [emoji231]
 

tidefan1967

Senior Member
Supporting Member
Joined
Feb 3, 2018
Posts
2,941
Reaction score
4,862
Location
Summerville, South Carolina
Do you live in a hilly area? My old RAM with the 8spd auto and 3.21 gears would downshift a gear when going over hills with the stock rubber so I think its pretty normal if you do have 3.21's.
 

Ohio5pt7

Senior Member
Joined
Jul 26, 2018
Posts
2,207
Reaction score
1,784
Location
Ohio
Ram Year
2018
Engine
5.7 hemi
I have a 18 CC 4x4 5.7 with 3.21s @ 70 it will search a little with the stock tires on hills. Planning to do a tune and long tubes. My vararam seemed to help it a little. As far as towing I have a 30ft 7500lb loaded TT I've towed 1k miles each way thru mountains and old betsy will gain speed going up if you want her to so it's not a power issue. It's the crappy stock tuning.

Sent from my SAMSUNG-SM-G891A using Tapatalk all grammar errors brought you by fat fingers and auto correct.
 

Graygoose

Indecisive Car Owner
Supporting Member
Joined
Nov 21, 2011
Posts
16,824
Reaction score
31,460
Location
Oklahoma
Ram Year
Convert, for now.
Engine
small
welcome, I'm just north of ya @BFeist


I put 35's on mine and didn't change speedo. so with your 33's, you should be fine.
 

Jofus

Junior Member
Joined
Nov 27, 2015
Posts
16
Reaction score
9
Ram Year
2015
Engine
5.7l
You guys recommend I get the gears changed out for this tire size increase before towing something significant? I plan on keeping it for years to come. Thanks!

Quick questions:
1. What factory gears do you have?
2. Are you using a heavier Uhaul car hauler
3. How far are you towing the Altima?

I have the 5.7, 8 speed, 3.21 gears. I have 33" Goodyear Duratracs on OEM 17" wheels. I towed my Jeep J10 a few times and never noticed when i swapped tires except the sidewall flexed a bit more. Granted when i was towing it was only four hours each trip.
 

Burla

Senior Member
Military
Joined
Apr 28, 2012
Posts
23,115
Reaction score
44,461
Ram Year
2010 Hemi Reg Cab 4x4
Engine
Hemi
just drive in tow haul 24/7, maybe don't go above 70.

It has a problem staying above 70 without downshifting? That isn't good.
 

Tim Garceau

Banned
Joined
Jun 29, 2018
Posts
2,090
Reaction score
2,408
Location
Eagle River
Ram Year
2014 Sport Quad BSP
Engine
3.92 8 Speed 5.7 4X4
Sounds like 3.21 gears and heavy wheel setup, so you don’t have the engine torque to keep the trans from downshifting.
 

crackerjack1957

Senior Member
Joined
Sep 26, 2015
Posts
2,016
Reaction score
2,379
Ram Year
2014 Sport 1500 CC 4x4
Engine
Hemi 5.7...65RFE...4.56
60psi of helium in each tire.........LoL

If you plan on towing you definitely need 3.92 gears.

 
Last edited:

grizzstang

Senior Member
Joined
Apr 26, 2017
Posts
1,691
Reaction score
2,442
Location
Calgary, Alberta Canada
Ram Year
2017
Engine
Hemi 5.7
Sounds odd, I went from the stock 33's to 34's in an LT so they are taller by 1" and considerably heavier.

I really didn't notice any power loss but I do have 392's and fixed the speedo with my ProCal.
 

69GWC

Power Wagon
Joined
Oct 1, 2015
Posts
5,387
Reaction score
6,949
Location
Spring hill, Kansas
Ram Year
2022 Power Wagon
Engine
6.4 Hemi, 8sp
A heavier taller tire is going to effect it staying in 8th gear on anything but flat ground with 3:21s.
I have 35s and just lock it in 7th most times , but my truck has zero problems running 90mph and pulls my 7k plus trailer with ease and also has 3:21s.
 
OP
OP
B

BFeist

Junior Member
Joined
Feb 18, 2020
Posts
4
Reaction score
1
Location
OKLAHOMA CITY
Ram Year
2013
Engine
5.7L Hemi
Good to know. Thanks everyone. Not sure which gear setup I have on the truck exactly, and currently deployed so I cant check it for a few months yet. I believe it's the 3.21 which would explain a lot. I've had the truck briefly over a hundred, and it can definitely pull itself up any hill no problem. I was just concerned about the consistent downshifting at highway speeds. Its almost if theres any incline at all, it feels the need to kick out of overdrive to maintain above 70. Whenever and wherever I end up towing the car to, I do plan on using a 2-wheel car dolly and driving in tow/haul around 65-70 to save the tranny the best I can. Just trying to gauge if the job is worth doing before that time comes. Thanks again.
 

69GWC

Power Wagon
Joined
Oct 1, 2015
Posts
5,387
Reaction score
6,949
Location
Spring hill, Kansas
Ram Year
2022 Power Wagon
Engine
6.4 Hemi, 8sp
When ever you tow I would also lock it in 6th gear so it stays out of the over drive gears.
 

Tracy in IL

Senior Member
Joined
Mar 24, 2018
Posts
287
Reaction score
171
Location
Moline IL
Ram Year
2017
Engine
3.0 diesel
for 2017 model year, standard tires were 31", except for Rebel which came with 33's. If you have 3.21 gearing, it may be contributing to your problem. My service mgr said with 3.55 or 3.92 gears going to 33's will not be a problem nor affect warranty.
 

grizzstang

Senior Member
Joined
Apr 26, 2017
Posts
1,691
Reaction score
2,442
Location
Calgary, Alberta Canada
Ram Year
2017
Engine
Hemi 5.7
^^^I think most of the models actually came with 20" wheels and 275/60R20 tires which are considered 33's.

The Tradesman and the Rebel came with 17" wheels and I am sure there are a few others.
 

Latest posts

Staff online

Forum statistics

Threads
194,926
Posts
2,864,176
Members
155,296
Latest member
VLG6963
Top