Advice on gear ratio

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.

OP
OP
the codes

the codes

Senior Member
Joined
Jan 8, 2012
Posts
4,210
Reaction score
160
Location
Houston, Tx
Ram Year
1998
Engine
Magnum 5.2
Not worth it ... IMO . Those gears are just to low for a full size truck . Why they come from the factory is beyond me

agreed

If you have that kind of money to spend you have enough to not even think about gas mileage. Who care about MPG when you have thousands to throw into rims,tires & gears?

well, im a college student and my grades are good, so scholarships have covered my expenses. I figured besides putting money into my retirement fund since social security will most likely dry up by the time I retire, that i mind as well have some fun with my money while I can before I can married and have bills and my wife and kids steal all my money...haha

Opinions on gears...about as varied as the trucks and ther owners themselves.

One thing is constant...the more unsrung weight you add from large tires and the more weight you add to your truck, the more torque you need to get that mass moving.
Gears are torque multipliers, simple as that. They are also horsepower bleeders, thats why you lose top end when you install them.

Its also unfair to compare a cummins truck, which makes around 400 ft/lb of torque to the same wheel base gasser, which makes around half that.

So....rather than give an opinion, I present a handy dandy chart that helps you determine what a gas vehicle should gear to.
Remember...Multiply the given rpm by .85 to get your overdrive rpm at 65 mph.

Tire & Gear Ratio Chart at Morris 4x4 Center


For the OP's application, if you are going to run a 35 inch tire, with a wider heavier rim, you should be running 4:56's You'll be running 2418 rpm in OD at 65. That will hurt your mileage slightly, but no worse than bucking a headwind with a full load and the OD off... with 4:10s.


On the subject of 3:92 gears, one should notice that with 33 inch tires there is only a 132 rpm difference between 3:92s and 4:10s, but 240 rpm between 3:92s and 3:55s! In OD that works out to 1997 and 2200 for the 3:92's 2200 rpm is about the torque curves' sweet spot in a mild magnum V-8.

thanks for your advice, that was a nice sum up.

and thanks to everyone else for all of your opinions.

I am thinking because I do alot of city driving, prob about 3x if not more than highway, that 4.56's coupled with a scanquage that my mileage might actually pick up. and I rarely go over 70 on the highway anymore after I got a ticket for going 85 and had to go through a pain of the ass process to get it dismissed -_-

keep the opinions coming
 

smiley

Senior Member
Supporting Member
Joined
Apr 18, 2011
Posts
6,622
Reaction score
2,955
Location
Minot, ND
Ram Year
2014 Ram 2500 Crew
Engine
6.7L Cummins
What would you recommend in my situation?

I rarely pull a trailer, but when I do is a 6x12 (Uhaul) less than 2k lbs wet.
I mainly do city driving with mixed highway.
I want to maintain decent gas mileage (14cty/18hwy)
And once every other month we drive a 500 mile round trip to the in laws.

4.56 rocks in town man it does add a littler to highway RPMS but worth it IMO. It does allow you to tow more as well especially when you have a big load and need to get it moving.
 

Stangshcky12

Senior Member
Joined
Oct 26, 2011
Posts
9,047
Reaction score
941
Location
Oshkosh, WI
Ram Year
2007
Engine
5.9 Cummins
4.56 rocks in town man it does add a littler to highway RPMS but worth it IMO. It does allow you to tow more as well especially when you have a big load and need to get it moving.

Not actually more but lets you tow heavier things with more ease
 

smiley

Senior Member
Supporting Member
Joined
Apr 18, 2011
Posts
6,622
Reaction score
2,955
Location
Minot, ND
Ram Year
2014 Ram 2500 Crew
Engine
6.7L Cummins
Not actually more but lets you tow heavier things with more ease

NO

I meant what I typed you CAN tow more because you can get more weight moving from a dead stop.

Example because I have numbers readily available

2012 Ram Laramie Crew with 1 passenger 4x4 is rated to tow 7072 lbs with 3.55 gears while the same truck with 3.92s is rated to tow 8572 lbs.
4.10 would increase and then 4.56 even more. Top speed also goes down as these numbers increase because engine will redline sooner.

Think of riding a mountain bike it works the same way

I used to work at a Cemetery in highschool and we had a dumb truck with highway gearing and if loaded too much could not even make the wheels turn but had another GM with the same 350 but lower gears that could get that same load moving in same spot and equally overloaded.
 
Last edited:

Stangshcky12

Senior Member
Joined
Oct 26, 2011
Posts
9,047
Reaction score
941
Location
Oshkosh, WI
Ram Year
2007
Engine
5.9 Cummins
You cannot change your tow ratings, they are what they are as the truck comes out of the factory.
If your truck came with 3:55s and you put 3:92 in it you can't just use the 3:92 GVWR/GCWR
Yes your truck can handle the extra weight but you take a HUGE liability should you go over the factory number.
 

smiley

Senior Member
Supporting Member
Joined
Apr 18, 2011
Posts
6,622
Reaction score
2,955
Location
Minot, ND
Ram Year
2014 Ram 2500 Crew
Engine
6.7L Cummins
The point is not that you are changing your government tow rating. It is that gears change what the truck can do. The rating from factory is increased as gear ratio is increased with other factors equal because of this.

Imagine trying to start in 2nd on a manual with a heavy load. Tougher or mayeb impossible. Now since it is automatic it will just keep trying (not kill engine) but it may never be able to actually move the load.

Yes at these types of weights the is truck trying to pull more than it is rated for but I think if your checked around most people either tow and haul (payload) very little or they overload the truck via hauling or towing and that is when gears really play a larger factory than just RPMS and fuel mileage.

Reality is people overload trucks of all sizes from a Dakota up to a 5500 they all are made for certain limits but I have seen many people using a 1500 for 2500 job and 2500 for 3500 job myself included.

Also forgot to mention the factory rating on a 1500 is skewed more than others because the truck comes with passenger rated tires unless outdoorsman so ability to safely two would increase instantly when someone upgrades to LT tires.

Same trucks as in my previous post but an Outdoorsman would go from 8500 towing to 10000 towing just by going from 3.55 to 3.92 gears so imagine the change my truck has for ability even if not actual rating when I went from 3.55 gears with P series tires to 4.56 gears and LT tires!

NIGHT AND DAY my friend
I personally do not use my vehicle for business just personal so I would not feel bad towing 10000 properly configured of course.

I looked up heavy duty trucks to see and same holds true

Cummins auto 4x4 3500 with 1 passenger goes like this
3.42 - 9650 lbs
3.73 - 13650 lbs
4.10 - 16650 lbs

all other factors the same the ratio impact is staggering on these trucks.
 
Last edited:

Hotroder383

Senior Member
Joined
Jan 7, 2012
Posts
235
Reaction score
5
Location
Washington Mo
Ram Year
1996
Engine
318 or 5.2 which ever you want
keep in mind that towing cap is not just determind by gears but also Brakeing! You can get any truck to move a load with right gears but w/o the right breaks you may be buying someone a new car cause you couldn't stop in time.
I personally use trailer breaks when ever I can and upgrade the brakes as soon as I do the performace. just sayin =)
 
OP
OP
the codes

the codes

Senior Member
Joined
Jan 8, 2012
Posts
4,210
Reaction score
160
Location
Houston, Tx
Ram Year
1998
Engine
Magnum 5.2
keep in mind that towing cap is not just determind by gears but also Brakeing! You can get any truck to move a load with right gears but w/o the right breaks you may be buying someone a new car cause you couldn't stop in time.
I personally use trailer breaks when ever I can and upgrade the brakes as soon as I do the performace. just sayin =)

I have wanted to convert my drum brakes in the back to disk for the better stopping power but to do so would be somewhere between 500-1000 I think, and I dont tow often, sometimes a little trailer with a few small farm animals like a pig or lamb, or sometimes sand, but thats not often whatsoever, so for now Ill prob just get some nice pads for the front when the time comes, and get the drum shoes redone since they probley havnt been swapped since my dad bought her in 98...lol
 

Stangshcky12

Senior Member
Joined
Oct 26, 2011
Posts
9,047
Reaction score
941
Location
Oshkosh, WI
Ram Year
2007
Engine
5.9 Cummins
So like I said, you can't change how much your truck can tow but you can help it handle the weight.
Yes if you buy a truck with 3:92 it has a higher tow rating the a truck with 3:55, but those numbers will never change.
In all honestly following someone with a trailer scares the **** out of me anymore. Hardly anyone understands what properly equipped means or how to decipher GVWR/GCWR
I do haul regularly and for work, I've been trough DOT inspections. While its not not likely to happen in a recreational vehicle and it really sucks.
A bigger concern is having an accident while you are over payload. Your insurance company has a right to drop to claim an put the responsibility on you. God forbid someone is seriously injured or even killed.
 

Big Boi

Senior Member
Joined
Aug 31, 2011
Posts
2,314
Reaction score
180
Location
S. Fla
Ram Year
2009
Engine
Hemi 5.7L
Wheres a good site to buy gears, so I can get an idea of the cost. And Which brands?
 

Big Boi

Senior Member
Joined
Aug 31, 2011
Posts
2,314
Reaction score
180
Location
S. Fla
Ram Year
2009
Engine
Hemi 5.7L
I would assume I have a 12 bolt - 9.25 rear diff?
 

quietpeen

Senior Member
Supporting Member
Joined
Jul 14, 2010
Posts
25,442
Reaction score
3,905
Ram Year
2021 TRX
Engine
Hellcat
check with our vendor 3rd strike also
 

smiley

Senior Member
Supporting Member
Joined
Apr 18, 2011
Posts
6,622
Reaction score
2,955
Location
Minot, ND
Ram Year
2014 Ram 2500 Crew
Engine
6.7L Cummins
keep in mind that towing cap is not just determind by gears but also Brakeing! You can get any truck to move a load with right gears but w/o the right breaks you may be buying someone a new car cause you couldn't stop in time.
I personally use trailer breaks when ever I can and upgrade the brakes as soon as I do the performace. just sayin =)

You are correct that is why properly equipped comes in. The brakes on the truck are only capable of so much no doubt. The trailer is the key factor at that point and must have some form of working brakes on it. The manaufactured rating is what I am using to point out ability of the truck when upgrades are made the rating would go up from the factory but since aftermarket rating does not go up but capability does go up but should not exceed what original ratings could be if you want to be safe about it.

The Codes have you decided what you will do/ get?
 
OP
OP
the codes

the codes

Senior Member
Joined
Jan 8, 2012
Posts
4,210
Reaction score
160
Location
Houston, Tx
Ram Year
1998
Engine
Magnum 5.2
I like Randy's ring and pinion, have contacted them before and they are pretty responsive and friendly.

I am leaning towards the 4.56's, I think they are a good fit for my mostly city driving, off roading, and on the highway I think even though I'd like to go 85 the 4.56's will keep me honest at going 65-70 which means no more tickets for me lol
 

Big Boi

Senior Member
Joined
Aug 31, 2011
Posts
2,314
Reaction score
180
Location
S. Fla
Ram Year
2009
Engine
Hemi 5.7L
I like Randy's ring and pinion, have contacted them before and they are pretty responsive and friendly.

I am leaning towards the 4.56's, I think they are a good fit for my mostly city driving, off roading, and on the highway I think even though I'd like to go 85 the 4.56's will keep me honest at going 65-70 which means no more tickets for me lol

That makes me want 4.10's more, lol :baby:
 
Top