Which F350 Axel Ratio.

[traveldawg]

Which axel ratio for an F350, CC, SRW, Power Stroke.....

3:31 - non-limited slip
3:55 - electronic locking

Seems the 3:31 will yield somewhat better fuel mileage (all-be-it I'm not sure that matters).

I'm not sure if one has a better tow rating/weight rating than the other.

[mlh]

I didn’t know they made a 3.35 a 3.55 but not a 3.35. But still I would go with the E locker. I see no reason not to. They are nice to have.
Lynwood

[traveldawg]

Originally Posted by mlh

I didn’t know they made a 3.35 a 3.55 but not a 3.35. But still I would go with the E locker. I see no reason not to. They are nice to have.
Lynwood

Lynwood,
oops.... typo... fixed... 3:55 thanks for pointing that out and the suggestion for a locker

[BB_TX]

I have the 3.55 on my 2012 F350 6.7. Tows the Monty great over Colorado mountain passes. Only turns about 1,700 rpm at 70 mph on the highway. Don't think I would want a 3.31.

[scottz]

I have the 3.55 e-locker with an automatic so that is all I can speak of; it works well, engine has plenty of power.

[WeBeFulltime]

Originally Posted by BB_TX

I have the 3.55 on my 2012 F350 6.7. Tows the Monty great over Colorado mountain passes. Only turns about 1,700 rpm at 70 mph on the highway. Don't think I would want a 3.31.

My 2012 F350 4 x 2 has the 3.31 and I have no problem with it at all.

[pyoung47]

Size of tire/wheel is a factor. I have the 3.32 with 17 inch wheels on my 350 SRW. This equates to the same ratio as the 3.55 with 18 inch wheels. Unless you are towing a huge-mungous trailer, either should provide enough power with any sized wheel. I have seen a few of the 18 inch equipped trucks with the 3.32.

[mlh]

The 18 and 20 inch tires are the same diameter. The 20s have a narrower side wall which makes them more stable.
Lynwood

[topjustice]

If you get the SRW with the FX4 option, it will require 3.55 electronically locking rear differential, skid plates, better shocks and upgraded tires. 4X4 is also required with this package. It's a good package and not that expensive. I have it on mine and still get between 10 and 11 MPG while towing a 5er. I think the mileage difference would be negligible.

[airboatart]

I have a 2017 F350 DRW 4x4 with 4.10 still get 10 mpg while towing a 3721 RL

[topjustice]

Yes I've often heard that there is not much mileage difference between the DRW and the SRW. Same engine of course. Gear ratios will moderately affect mileage. Once you are heading down the highway why should mileage be affected? Going over mountains and slow driving is the biggest cause.

[waynemoore]

Add wind to that list. Also I once drove at 55 mph and got 12.4 mpg going to Ca from Az a 300 mile drive. Remember I said once and that was just to prove a point to myself. I do beleave if you want to drive yourself crazy drive 55 for a long distance. I don't think I will ever be right again. Lol. I like to run between 63 and 65 or so. Yes even in CA if one is not doing foolish things the CHP will leave you along.

[topjustice]

Originally Posted by waynemoore

Add wind to that list. Also I once drove at 55 mph and got 12.4 mpg going to Ca from Az a 300 mile drive. Remember I said once and that was just to prove a point to myself. I do beleave if you want to drive yourself crazy drive 55 for a long distance. I don't think I will ever be right again. Lol. I like to run between 63 and 65 or so. Yes even in CA if one is not doing foolish things the CHP will leave you along.

Maybe that wind you mentioned was pushing you down the highway and that's why you got 12.4.

[waynemoore]

Originally Posted by topjustice

Maybe that wind you mentioned was pushing you down the highway and that's why you got 12.4.

But here the prevailing wind is West to East.

well that is it's blowing east if you are going west and west if you are going east. It seams like it is always blowing the wrong way.

But seriously when there is a head wind our mileage goes down hill fast.
Tail wind is great and most times when heading east we do get a tail wind.