Gas Mileage- F350/F450/F550

Discussion in 'Trucks and Trailers' started by ToroLandscaper, Mar 12, 2010.

  1. ToroLandscaper

    ToroLandscaper LawnSite Bronze Member
    Messages: 1,177

    Can anyone tell me the gas mileage difference between F350, F450, and F550 (1999-2001 models with 7.3 diesel) on the interstate?

    Last edited: Mar 12, 2010
  2. ToroLandscaper

    ToroLandscaper LawnSite Bronze Member
    Messages: 1,177

    Also, if anyone could give me loaded vs. unloaded that would be awesome, lets say loaded with a 24' enclosed.

    I know this is really broad and I apologize, I am just trying to get a ball park
  3. WH401

    WH401 LawnSite Senior Member
    Messages: 571

    It depends on the rear end ratio, how fast your going, and how loaded/unloaded you are. If the 350 has a decent gear ratio, your not going to fast, and your unloaded, than you could expect some reasonable mileage out of it, but every truck is different. In the 450 and the 550 I wouldn't expect much mileage at all, most of them have 4.30 rear ends I would figure, not to mention the weight of them is against you as well. Honestly though, if your worried about fuel mileage in vehicles that big than I wouldn't look at them. If your buying one, fuel mileage is the last thing you take into consideration.
  4. stuvecorp

    stuvecorp LawnSite Fanatic
    Messages: 5,245

    I disagree on the fuel mileage thing, I want as good of mileage as possible and am willing to be a little slower if I get more fuel mileage. The 01 F350 I had must have had real high gears as I got 10-14mpg but the 07 F550 I think has 4.88's and I don't want to figure out what it's getting but it's turning ridiculous rpm on the highway. I am looking at changing the gearing to what my 350 had, they are towing the same stuff and I was satisfied with the 350's performance.
  5. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Messages: 9,544

    A F-450/550 with a 7.3 is only going to get at most 10-12mpg you will get 12 with a 6spd manual with the 4R100 automatic the enging revs higher.

    If your looking at a 6.0 F-450/550 the tallest gear you can get is 4:30 I wouldn't go any taller than that.

    A F-450 with 7.3 has the modified Dana 80 the tallest gear is 4:30 the F-550 has the S135 a expensive rear axle regearing it wouldn't make it worth the fuel savings most F-550s have 4:88 gears.
  6. rlong97150

    rlong97150 LawnSite Member
    Messages: 110

    I have an 01 F-550 with the 7.3 and the entire Banks package. It is our dedicated RV Hauler. Empty I get 18-20 and pulling our camper I average 12-13. Camper is a 37 foot 5th wheel that weighs in the neighborhood of 17,000 lbs. With the gearing I find the sweetspot is 55-62 so thats where I keep her. Truck has 115,000 miles on it and you will find a picture below. Definitely a beast going down the road.

    IceBergAbe likes this.
  7. bam

    bam LawnSite Senior Member
    from .
    Messages: 261

    we have 450's with the 4.88 gearing. they're pulling enclosed 24' trailers most of the time. Early season the beds are loaded with mulch. Trailers Gross weight is 10,000 lb. Usually three or four mowers inside them. That said, they average 6 mpgs.

    Rented a 550 a few times. Sucked down the diesel. So probably no more than 6mpg.

    I own an F250 with a 7.3l. Highway I might get 18mpg, but typical city/local driving I would be around 14mpg. I think my truck 3.73 gearing.

    A few years back the gearing on the 250/350 was 3.73 or 4.10. I think the 450/550 is maybe a 4.10 and more so the 4.30 and the 4.88.
  8. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Messages: 9,544

    Hard to beleive your getting 18 mpg gallon I think realistically 14 mpg.
  9. stuvecorp

    stuvecorp LawnSite Fanatic
    Messages: 5,245

    Here's my deal, I want something more like the 3.73's. I think the 350 had them and I got 13-14 on long trips and 10-12 around town and towing. Why can't the 550 have higher gearing?
  10. 360ci

    360ci LawnSite Senior Member
    Messages: 998

    550 requires lower gearing to better handle it's maximum payload should you decide to run it loaded to the max. I'd be content with the 4.3 gears, it's a good blend of around town pulling performance, and low speed highway cruising. Anything over 65mph, mileage will be below or around 10mpg depending on weight, aero drag of trailer, etc. Most trucks with the 4.88gears top out at around 75-80mph, at which it's not mpg, it's gpm.

    If you want highway mileage, you can always look into getting a larger diameter tire when the time comes to replace the stock set. A 3" taller tire can give you less performance around town, but lower rpm on the highway. Mileage won't be much more noticeable unless you're easy on the throttle and keep speeds down. The extra height can work against you some, as it will create more drag when air passes under the truck and smacks into the trailer.

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