With all things equal, i.e., 18" tires & 3.31 gears, is there a difference in MPG between the 250 & 350? I guess if there is any weight difference at all there will be, but is it significant? One MPG?

 

None. Mileage will be about the same. The bigger factors are rolling resistance and wind resistance and both models are the same there.

I've driven F250 with 3:31 & 18" wheels and gotten pretty much the same mileage my F350 with 3:55 and 20's gets.

 

Thank you for that info. I find that pretty interesting. Since the price difference between the 250 & 350 is only about $725, I'm trying to decide why not to just get the 350?

 

I personally own a '12 f350 cc/lb 3.31 w/18in wheels. Consistently avg 17 city 20hiway. I know four guys with 250s with 20" wheels and they are 15/18 mpg. We all use same fuel station and manually calculate mileage. Its sort of a contest!!

 

I picked up a used F250 with the 3.31 and 18" wheels for friend in Witchta and drove it back to SLC for him, 80 mph on the interstate for a little over 1000 miles and got 18 mpg for the trip. I did not do any city driving with that truck, so can't speak for around town mileage.

I consistently get 18 to 18.5 mpg on 80 mph interstate drives with my truck that is a F350, with 3.55 and the 20" wheels.

Same driver, same kind of driving, two different trucks but same mileage, Tells me there is very little difference. There is very little weight difference between the F250 and F350. Almost no difference in wind resistance. You will see more difference in mileage based up changing out tires or driver habits. Other than the springs and a little heavier axle shaft. they are the same trucks, So why would you expect a significant variation in fuel mileage?

As far as buying the F250. I agree, if you are buying a full size diesel truck, Get the F350. If you go over to my local dealer, probably 90% of the trucks he has in inventory are F350's. Which reflects the local demand.

 

My total average in the last 2 months with 50/50 city/highway driving according to my fuel logs and fuelly is 15.2 MPG in 3286 miles total tracked.
I drive a F-250 XLT super-cab long bed 4X4 3.31, I do drive 65-75 MPH on the freeway and love boosting half the time.

 

Yeah, I guess I just thought the F350 weighed several hundred lbs. more, since it is a 1 ton, vs. a 3/4 ton.

 

Weight is not a big issue to this trucks,

I pulled an empty dump trailer out to a stone quarry. It weighed 5000lbs empty. I loaded in 8000lbs of flag stone for project, so now the trailer and cargo weighed 13,000lbs and towed it back home. I got 1/2mpg difference for an 8,000lb lighter load.

Same results with two horse trailers. One loaded with horses and LQ weighed in at 16,000lbs. I towed a second trailer, same shape but empty trailer that weighed 6,000lbs and again got 1/2 mpg better mileage. 10,000lbs of added weight only took an extra 1/2 mpg of fuel. These are on 300 mile hiway drives. Not around town.

The 100 or maybe 200 lbs that a F350 weighs over a F250 will make almost no difference in your average.

 

Upgrading to the 350 puts you well over 10k GVWR. In some states that makes a big difference in registration costs. In those cases get the 250 and throw airbags under it.

 

You can actually purchase a 350 with a 10k gvwr option for that reason. Most are 11,500 gvwr. I would be surprised if the weight difference between the 250 & 350 is one hundred pounds. Far as i know its just the extra leaf in the rear.

 

not to sure about what the 10,000 GVWR entails but my car had it as a no cost option to rate it at that or under, they told me it makes registration cheaper but I say the only difference in weight will be trim, not model number.
4x4 or not, long bed short bed super cab crew cab and so forth. also 20" wheels may net you lower mpg.

 

On the F350, the 10,000 GVWR down grades the total weight the truck can be registered for. Which in some states does make the registration cheaper. Here in Utah it doesn't matter, annual registrations are based on pickup trucks $ value not it's GVWR. Maybe that is way we see very few F250s around here.

As far as the difference, F350 has the extra leaf spring, a heavier diameter axle and 37 instead of 35 splines on the axle. The 2011 F350's had Hydraulic Assisted brakes where the F250s had the Vacuum Assisted brakes.

 

I just finished a 1400 mile road trip from Santa Fe to Tucson and back unloaded and not towing. Most of the driving was interstate at 70 mph. With some local day trips in Winslow and Tucson and a 50 mile route on the return on a mountain road over 9000 feet, I averaged about 20 mpg with the best tank at 20.7 mpg (hand calculated). F250, 4x4, SB, CC, 3.31, cab high shell

 

GVWR does make a diff. in fees in Ca. They'd tax the air you breathe if they could get away with it.