The 1500 only came with 2 ratios. 3.55 and 3.92.

You don't need to change the ratio for occasional towing like the guys above said.

You didn't say what wheels/tires you have and I'm guessing you have stock 20's.

If you actually do go with bigger tires, then you'll have to rethink the gear change, ESPECIALLY if you are going to tow with them.

 

I went to 35s with a 4" suspension lift and it felt like it lost half it's power, especially at low engine rpm's. Went to 4.56 gears and it felt like it had more power than when it was bone stock...

 

actually i have the off road rims and tires. i forgett the tire size right now but they are some goodyear wranglers and the rims are the 17x7 that have come on the rams since the 2nd gen. i really prefer em over the 20's!!!

 

3.92 is fine, ive hooked 9500 pounds (dont tell dodge) and ive got a 4.7, its a truck people, not a car. Now if its gonna be used to tow more than a few times a year then yeah 4.56 is the way to go esp if youre considering larger tires, tires and a trailer will put a lot of strain on your vehicle. 3.92 to 4.10 only if it comes free with an oil change, not worth the money. just be glad you dont have the 3.55

dont forget the most important part about towing, it aint how much you can tow, its how much you can stop.

now aint someone gonna explain what the numbers mean??? nobody..
ok take the number of teeth on the ring gear and divide by the number of teeth on the pinion gear. dirt simple -- 3.92 means 3.92 revolutions from the smaller gear to make the larger gear turn 1 revolution.

 

If you are going to lift and go to 35's then definetly go to 4.56 - it will reduce the strain on the drivetrain and will bring your mileage back to stock if not better.

 

http://science.howstuffworks.com/gear-ratio2.htm

 

Going to 4.56s will be my next mod. I pull a 4000lb+/- boat with my 3.55s and don't have any issues, but I like the low end power a gear change will give me as well as the fact I will be going to larger tires.

The gears you have now are a good all around gear, as soon as the pulling and big tires come in a gear change would be recommended.

 

I agree. The gears to go with if you get bigger tires and/or tow should be 4.56s.

 

the actual number of gear teeth on pinion and ring are listed here:

http://www.drivetrain.com/chrysler9.25.html

Do you want to tow heavy loads at highway speeds
with bigger tires that lift your truck's 'center of gravity'
and make it more likely to:

roll over
sway in wind without a trailer
sway even worse with a trailer (tail wags the dog)
stop poorly
get worse fuel economy as air flows under rough side

To then compensate for the bigger diameter tires
with a $1200 diff gear change
isn't that following one mistake after another?

The state motto of North Carolina is:

"esse quam videri"

To trully be, rather than to seem to be

The lifted truck/big tire crowd
seem to have an entirely different philosophy of life

 

No Hank if someone wishes to modify their vehicle, it is not a mistake andas hard as you try to fight it - mods - actually do work - there are tons of dodge ram owners who have done the math and taken the leap to 4.56's and are getting better gas mileage in many instances or have restored their mpg to what it was before a lift and bigger tires as well as improving the everyday driveability of their truck.