4.30 Gears Help

[semperfidooordie]

I have an 08 F-350 DRW 4x4 with 4.30 gears...I know it's a 6.4 and a dually so I don't expect amazing mileage but where I live now I drive relatively short trips to and from work approx. 8 miles. I was wondering since I need tires anyway if it would be more beneficial to get taller tires (33s, 35s or 37s) or swap gears to a 3.73 or so and still be in need of new tires. I've also considered swapping to a wide SRW wheel and running some taller and wider tires but 4 all around instead of 6. Any advice?

 

[JoeDaddy]

I have an 08 F-350 DRW 4x4 with 4.30 gears...I know it's a 6.4 and a dually so I don't expect amazing mileage but where I live now I drive relatively short trips to and from work approx. 8 miles. I was wondering since I need tires anyway if it would be more beneficial to get taller tires (33s, 35s or 37s) or swap gears to a 3.73 or so and still be in need of new tires. I've also considered swapping to a wide SRW wheel and running some taller and wider tires but 4 all around instead of 6. Any advice?

I'm in the same boat, Randy's has front and rears for like $1200. I'm thinking of going with 3.55's so I can stay with 235/85's

 

[semperfidooordie]

I really want to go to bigger/more offroad friendly tires since where I live is all desert and mostly offroad/out in the middle of nowhere driving but wasn't sure what the cost vs benefit was....I like the down low grunt of the 4.30s but don't tow heavy often so it's not a necessity.

 

[semperfidooordie]

Wanted to throw another question out there...has anyone with 4.30 gears gone to a taller tire? If so has anyone seen an increase in mileage? I figured with the torque of a diesel the weight shouldn't bother it at all but the increased height seems like you'd turn lower RPMs on the freeway.

 

[sirnunya]

gear swap would be a waste of time and money, IMO. It would take a hell of a lot of 8 mile trips to make up the fuel savings.(might actually make MPG worse in the city, but better on highway where you can cruise at lower rpm) I would buy slightly taller tires , since you need them any way.

 

[Lowdown89]

I'm in the same boat somewhat, I'm running 4.10s in my dually and I really wanna swap to a 3.55 or 3.73 I never tow heav enough to need the 4.10s and I would love the rpm drop on the highway.... Not to mention every time I run somebody it's from a roll and with the 4.10s I run out of gear way to quick!

 

[rc4wd]

I'm runnin 35's with 4.10's and it helped my fuel mileage slightly and I'm still able to tow heavy with ease. I would definitely run a larger tire before I went through the trouble of a gear swap.

 

[semperfidooordie]

Awesome to hear guys. Thats what I was thinking as well

 

[Betarocker]

Don't change the gear to try to save fuel dollars. The cost to do the swap will take years to recoup. The reason to swap gears is to let the engine spin at its prime RPMs in the normal driving you do.

 

[Jeff]

dont forget that taller tires = more strain on the motor and trans. With the 4.30 you got less strain on your truck. I have a 4.30 and my tire size equals about a 31" or 32" and my speedo is almost perfect.

 

[semperfidooordie]

That's a good point but with that wouldn't it make sense that a taller tire wouldn't put as much strain on the motor since I'm running 4.30 gears

 

[Jeff]

That's a good point but with that wouldn't it make sense that a taller tire wouldn't put as much strain on the motor since I'm running 4.30 gears

Yeah thats what Im trying to say lol. Most people who go with bigger tires want bigger gears.

 

[semperfidooordie]

Rofl my bad..I probably shouldn't get on here after one took many beers

 

[sirnunya]

dont forget that taller tires = more strain on the motor and trans. With the 4.30 you got less strain on your truck. I have a 4.30 and my tire size equals about a 31" or 32" and my speedo is almost perfect.

That engine must be screaming out on the highway. I had 38's and 4.56's and hated long highway drives

 

[semperfidooordie]

I'm on stock tires (245/75R17) and 4.30s and mine screams at highway speeds for sure. 60 mph puts me right at 2k...it's miserable and the mileage is the same.

 

[HaysKSFirefighter]

I'm on stock tires (245/75R17) and 4.30s and mine screams at highway speeds for sure. 60 mph puts me right at 2k...it's miserable and the mileage is the same.

Same here...2500+ rpm on the interstate just to keep up with traffic and not get into a wreck is no fun at all.

 

[semperfidooordie]

Seriously man...would have reconsidered this specific rig had I realized that. But at the same time don't wanna swap gears...just going to go with a bigger tire and see how it pans out