2nd Gen Non-Engine/Transmission Tire Size, Gears, & MPG's

[JohnHaney]

after searching posts it does seem everyone has their own opinions on what the "best" choice in tire size/gears should be. i have just put on 35" tires on my 01' truck with 3. 54 gears and have noticed a considerable drop in mpg's. previously i was running 33's and was getting decent mileage 19's around town. i would like to get some of my mileage back by swapping out gears, just don't know if i want to go 3. 73's or 4. 10's. what combinations are you guys using and what kind of mileage are you getting?



put on a kelderman air ride system too, so the overall weight of the truck has increased some as well, i am thinking that has caused some of the decrease as well.

 

[EKlem]

How is the truck used. You mention your around town mileage, is that what you primarily do?

If you are going for city mileage, going to a 4. 10 is going to help you the most although the benefit won't be very much. You want to go with the numerically highest gear ratio you can without sacrificing your top end for around town mileage. It makes the truck easier to get rolling and provides you with more gear options so that you can run in the correct rpm band more of the time. The increased rotational inertia of those tires is really hurting you.

 

[JohnHaney]

it is my daily driver, so the majority of driving is around town, but i also take it on longer trips, once a month on average. i sell hay in the winter and have horses so i do some towing too, two horse gooseneck trailer and 25' flatbed gooseneck. prior to swapping tires i was pretty happy with mileage in general, around town, towing, and on the highway. last time i hauled hay i had 14, 600# round bales on and got 14 mpg's, a lot of which was highway driving around 70 mph, which kept my rpm's pretty close to 2000, which is where it likes to run and make good power. i know i will have to sacrifice highway or around town but i would like to get back to a good middle ground. prior to the swap on the highway going over 2000 rpm hurt my mileage but if i kept it at 2000 rpm, speed was 75mph and it did well, i think i would like to get back to that range.

 

[tgordon]

If you do some searching you will find formulas that will take what your current ratio between the ground and the engine are and get them to what you want it to be. Other wise you will have to know the differance between the revelutions per mile and that varies between tire styles.

 

[Regcabguy]

I went from 3. 54's to 3. 73's on my '99. Barely noticible. 4. 10's and the 35's if you're going to keep that size is pretty nice. I've currently got the same gearing equivalent on my '07 g-56. It needs 35's badly. I just wish they'd release a thinner tire for better mpg.