Help with Gearing!

[powerstroke619]

I have a 2005 6.0L crew cab short bed and I recently added larger rims and tires. The truck got real sluggish and my MPG is at 10. I'm assuming the fix will need to come via gears, if the stock gears on my truck are 3.73's my guess would be to add 4.10's for the new set up.

The new tires I'm running are 325/60/18, are 4.10's the right choice?

[ODAWG714]

I'm running 4.30s and love em. You down in sd? If your near Anaheim you can try my truck with the 4.30s

And I believe the 325.60 is like a 36in tire I have two n my garage.

[Dirty_Stroke]

I've wondered how 4.30's would do with a 35/36 inch tire. I have pondered the idea of putting them in my truck to get some mileage back. I didn't know if it would hurt or help mpg, I know it'd be a lot stronger down low.

[Evil Eye]

Originally Posted by ODAWG714

I'm running 4.30s and love em. You down in sd? If your near Anaheim you can try my truck with the 4.30s

And I believe the 325.60 is like a 36in tire I have two n my garage.

The 325/60/R18 is a 33" tire and is about 13" wide. You are probably thinking about the 326/65/R18, which is roughly a 35x12.5 tire. I used to run the 325/60's and have switched to the 305/55/R20 which is roughly the same dimensions but a touch more narrow (33x12). I'm also running 3.73 gears, but the cost to change them out is roughly $1k in new gears for front and rear and the master install kits, PLUS another $1k in labor to have them installed.

Since I tow, I am considering going to the 4.30's to help regain some of my mileage as well as gain some mechanical advantage pulling some of the steep grades with my toy hauler. Otherwise, I would be going the route with the 4.10's...

PS. It's going to take some serious fuel mileage increases to get your return on a $2k investment...

[ebusa]

Originally Posted by powerstroke619

I have a 2005 6.0L crew cab short bed and I recently added larger rims and tires. The truck got real sluggish and my MPG is at 10. I'm assuming the fix will need to come via gears, if the stock gears on my truck are 3.73's my guess would be to add 4.10's for the new set up.

The new tires I'm running are 325/60/18, are 4.10's the right choice?

Do you have an sct tuner? If not, you may consider it with some good mild tunes tow or street Much cheaper than gears. It won't be sluggish anymore

[windrunner408]

Originally Posted by powerstroke619

I have a 2005 6.0L crew cab short bed and I recently added larger rims and tires. The truck got real sluggish and my MPG is at 10. I'm assuming the fix will need to come via gears, if the stock gears on my truck are 3.73's my guess would be to add 4.10's for the new set up.

The new tires I'm running are 325/60/18, are 4.10's the right choice?

4.10s are the right gears for those tires. It would actually be a little too much gear (kind of like 4.30s with 35s) but based on what is available it is the next size up and would be close enough. The thing to keep in mind though is I have yet to see/hear of anyone who regeared their truck and actually regained mileage back. You will most certainly gain low end torque and maybe some mileage if you only drove in the city but if you do any driving on the hwy I wouldnt think you would gain much if anything at all. I could be wrong. JMO.

[Dirty_Stroke]

Originally Posted by windrunner408

4.10s are the right gears for those tires. It would actually be a little too much gear (kind of like 4.30s with 35s) but based on what is available it is the next size up and would be close enough. The thing to keep in mind though is I have yet to see/hear of anyone who regeared their truck and actually regained mileage back. You will most certainly gain low end torque and maybe some mileage if you only drove in the city but if you do any driving on the hwy I wouldnt think you would gain much if anything at all. I could be wrong. JMO.

Yea I was thinking 4.30 might be too much gear on the highway for a diesel on 35's. I have 4.10's in my Rubicon on 35's and it's kind of sluggish above 50mph, but I know it doesn't have near the torque lol. I ran 4.88's in my old CJ on 36's and it hold plenty of pep! But i was in 4th gear by 40mph.

[ODAWG714]

I just measured my 325.60r20 and they are 35.5 in and they are bigger then my 35's that I am running.

[powerstroke619]

Yes I'm in San Diego...

I'm actually looking for a spare tire for an extra rim I have, let me know if you're interested in selling a tire or two.

[powerstroke619]

Originally Posted by ODAWG714

I'm running 4.30s and love em. You down in sd? If your near Anaheim you can try my truck with the 4.30s

And I believe the 325.60 is like a 36in tire I have two n my garage.

Yes I'm in San Diego...

I'm actually looking for a spare tire for an extra rim I have, let me know if you're interested in selling a tire or two.