How much difference in fuel mileage between these gears? 3 or 4 mpg or more? I really like the looks of the wide trac axle,just wondering about the mileage. Thanks

 

Get the wide track with 3.73s.

 

I was told it was only available with the 4.30 gears.

 

the difference between 3.73 and 4.10 gears is 200 rpm on the highway....4.10 to 4.30 is another 100 rpm

so with 4.30 gears your turning around 2500 rpm at 70 mph

 

I would say 1.5 - 2 mpg more with the 3.73. The wide track front end is phenomenal. The turning radius is fantastic!

 

can you get the wide track with 3.73's?? I thought it was only available with the 4.30's.

 

You can get the Widetrack with the F-350 with 3.73 gears. In the F-450, you can only get the 4.30 gears.

 

If you were talking to a dealer he may have told you what he had available...not what you can order or find elsewhere.
You can build a F350 on the website with 3.73s and the widetrack.

 

I installed 3.73 gears in my F450 and I am very happy with it.

 

F250Wheels - the 3.73 swap for your 450 sounds great for running empty or pulling a trailer a speeds greater than 60 MPH on flat ground, and a lot cheaper than an $3k overdrive for the little bit of empty running that I do. What did that swap do for your empty and towing mileages on your duelly 450? Do you pull heavy loads? I am right at 26k combined weight with my 40' high profile 5th wheel camper and wonder how/if that might work from your perspective. Pulling and stopping camper is 85% of use, and why I bought truck - which is a dream to pull with; but running empty I feel like a fuel fool.


For others, as most of you know both rear ends and tire sizes affect final RPM's. The standard 32 inch diameter tires on 19.5 rims (225/70R/19.5) that come on a 450 with a 4.30 rear has me running 2,250 engine RPM's at 70; hard to read but guess about 1,900-1,950 RPM's at 60 MPH. My 08 250 with 3.73 rear and Ford's optional 20" tires ran 1,500 RPM's at 60. My stock 450 setup is about the same RPM/final drive as a 250/350's with 4.10 with their standard smaller wheel/tire combos. So you might get the final drive ratio you want with the right tire combo.

The opposite is true for a 3.73 with 20 inch rims on a 250, equivalent to a 3.55 or so with the smaller standard tires. Most of the better mileage talk comes from those with big factory tire/wheel combos with 3.73 rear ends.

Original poster you are planning on heavy loads you might regret the 3.73 if you are near the mountains. (250Wheels response to my note to above may be helpful). Also, if you plan to pull a 5er, be careful of the height of the bed of the truck; Ford's optional tire size/off road packages can add almost 4 inches and cause pickup bed rail clearance problems on some 5th wheel campers.

JohnD333
sorry lost footer signature again

 

I pulled my 17k 5th wheel behid 3.73s in the mountains and had no problem whatsoever. The only reason I upgraded to the F450 was because of the tongue weight on single rear wheels just didn't feel safe.

 

66stang351,
I got out of my 250 for the same reason - tongue weight.
Last summer I was in New Hampshire, which is a lot easier than the Rockies, and my load with 4.30 450 was no fun, but that could have been the turbo that was replaced 5k miles later.

Now that I am in a duelly I wonder if the drag of the extra wheels will negate the economy otherwise associated with a 3.73 with my wheel/tire size; thus my question to F250Wheels. From other 450 reports, I understand a $3k overdrive provides a 1.5 MPG improvement, but final drive ration was not cited. I am not sure that OD could be engaged full time with a load, but if it could the payback on $3k would be 100k highway miles at $5/gallon. A rear end swap would be lots cheaper and faster payback, so await F250Wheels' reply; and I could always do only one and swap back if I did not get the same results.

 

Right after I got the heavier trailer I pulled it from California to Oregon and with the 3.73s the truck would drop a gear and pull a 6% grade at 50MPH with no problems.

As for the OD, I have a Gearvendor in my 450 and don't use it pulling as it just drops a gear in the transmission unless it is flat and level or down hill. Driving empty I went from ~14-15 up to ~16-17 cruising, and my truck is used about 90% empty. With 3.73s in the F350 60MPH was 1750RPM, with the 4.30s in the F450 it was 2000RPM and with the GV it dropped to 1500RPM. Having the GV is like having a rear end ratio in the ~3.20s.

I figured like you did that the OD would take 100k to come close to paying for itself in fuel, but in addition to fuel running the engine and transmission at 75% of the RPMs when cruising empty saves wear and tear in the long run as well.

 

I was told today I can get the wide trac axle with the 3.73 gear but cant get limited slip with it. Is that a real big deal, with a 4x4 truck ?Not gonna be in the mud or pulling real heavy loads.

 

The limited slip is relatively useless anyway...get the 3.73s.