SRW vs DRW MPG

6 wheels on the ground compared to 4 wheels on the ground is not twice as much braking surface—1.5 times as much. Extra weight from heavier dually suspension reduces mileage. In Fords a dually always comes with higher numeric rear ratio making engine spin faster causing lower mileage. GM had a white paper out a few years ago saying diesels are more susceptible to reduced mileage from high engine RPMs than are gas engines. Luckily the low RPM torque peak in diesels lets you gear them for slow RPMs if you got a big enough engine. My son went from 7.3 regular cab long bed 16 mpg to 7.3 crew cab long bed dually 12 mpg. Your results may vary.

lenr wrote:
6 wheels on the ground compared to 4 wheels on the ground is not twice as much braking surface—1.5 times as much. Extra weight from heavier dually suspension reduces mileage. In Fords a dually always comes with higher numeric rear ratio making engine spin faster causing lower mileage. GM had a white paper out a few years ago saying diesels are more susceptible to reduced mileage from high engine RPMs than are gas engines. Luckily the low RPM torque peak in diesels lets you gear them for slow RPMs if you got a big enough engine. My son went from 7.3 regular cab long bed 16 mpg to 7.3 crew cab long bed dually 12 mpg. Your results may vary.

Well I assumed we all knew both trucks would have front wheels which is why I mentioned 2 wheel vs 4 wheels being twice as much:S

In your son case your just not comparing SRW vs. DRW. You are also comparing regular cab to crew cab.
If you keep chassis,engine size and all other factors equal and only compare SRW vs DRW MPG difference is negligible.

The only real difference between the trucks is that most dually trucks are 'expected' to carry more weight and normally get a much lower rear axle ratio, so the engine spins faster at any given road speed. This takes away MPG.

So if the truck has a 3.73:1 rear axle ratio with a SRW configuration and you compare that to a dually with a 4.10:1 or 4.22:1, the other trucks will spin the engine much faster at 65 MPH, leading to reduced fuel mileage.

Buying a 2005 and later SRW F-350, you will get a truck with almost the same cargo rating as the 99 Dually diesel. (gas could carry about 800 pounds more because the curb weight is much less). I think the 2005 and later SRW pickup has a 11,500 GVWR, while 2004 and earlier have only 9,900 GVWR.

You can verify in the towing guides put out by Ford.

http://www.fleet.ford.com/towing-guides/

Look up a truck model year, then towing guide will offer the maximum towing capacity and cargo rating for each model. Look for cargo rating in the 'slide in camper' section, it will tell the maximum that you can load into the bed of a truck.

Chances are that you can find a SRW V10 truck fairly cheap these days. Even the 5.4L SRW F-350 will work for a lighter fifth wheel.

Why not get a dedicated transport car with something like 30 MPG? I found that driving my Edge to work - 50 miles round trip each day cost me about $300 a month in gas. Driving a smaller car is only 1/2 that price, and saves $150 a month. Now the wife drives the Edge, and I drive this tiny Kia ecobox. She only need to drive about 15 miles per day. You should be able to pick up a smaller older Honda commuter car, or a smaller Toyota, and get that for back and forth transportation. IT will save putting more miles on the much more expensive truck too, so you will not wear out the truck taking it back and forth to work at 10,000 miles per year (in addition to the other miles that you must drive the truck).

Call your insurance agency before buying a car. I found that the Kia is much more expensive to insure than the Edge, because it is such a small car. The Edge is much safer, and if I had bought a Ford Fiesta, about the same cost, insurance costs would be less, because it is safer.

Good luck,

Fred.

Wow and I was just going to make a joke and spin the thread into small car vs big car something or other......hahaha but you all beat me to it!
First someone was giving diesel mpgs when the op asked about the V10 and srw vs drw and it just ran off from there.
This forum is like a train wreck. Just gotta see what is de-railed daily!

With my 05 dmax, I got about 2 mpg less than a sw equal. Both had the same axel gearing, size etc. BUT, being as you add about 150 lbs in tires, this is about equal to adding 1500 lbs to a sw bed from an hp needed standpoint. ALong with another 200-300 lbs in fenders, extra springs, some cases ie ford at one time a .003" thicker frame for the dually, all add up to extra needed HP, which will chew up fuel mileage. This is equal to adding about a ton of wt to a single wheel as far as HP needed to get it going vs a SW.

If you go with GM, IIRC a newer rig with the 6.0 gas, a SW has a 10.5" RA vs possibly an 11.5" RA in the dually. Could be wrong on this, so a bit more hp moving wt, which again, takes about a 10-1 equal vs sitting there wt.

Lower mpg setups like a gas rig, will probably be closer to a gallon, but could be closer to 2 as with the diesels too.

Just my general experience with multiple dual vs single setups since 81.

Marty

transamz9 wrote:

Lantley wrote:
The difference in MPG is negligible 1 MPG at most.
Whatever the dually lacks in MPG's is returned via additional braking power.
DRW vs. SRW MPG's is really a non issue.

I still don't understand the braking thing. The brakes are the same on the SWR as the DRW trucks unless a model change. I have never ever been able to lock up my rear wheels on my srw trucks while towing.

DRW trucks (Ford) get bigger rear pistons

Hi. Why are so interested in fuel mileage? You are towing another vehicle thats (dead weight). The higher you go less mileage you get.

jerem0621 wrote:
I had a 99 V10 3.73, Dually LB CC 2wd...I got about 9.5 empty and 7.5 towing.

How much is the dually MPG penalty? I mean, if my truck wasn't a dually, what would my MPG have been? Would it have been 10.5 empty or more?

Reason I am asking is because we are talking about getting back into RV'ing and I need a truck that can do double duty as a DD at 60 - 70 miles per day. The previous LB Dually had problems in my works parking garage so there is a strong likelyhood that I will have to go with a SRW Shortbed truck.

Thanks!

Jeremiah

On my 01 F350/CC/LB/V-10/4x4 I am always getting about 14-15 on the highway and getting 7-8 towing. That is with 3:73 gears. Just changed to 4:30's....will see what difference it makes.

transamz9 wrote:

Lantley wrote:

transamz9 wrote:

Lantley wrote:
The difference in MPG is negligible 1 MPG at most.
Whatever the dually lacks in MPG's is returned via additional braking power.
DRW vs. SRW MPG's is really a non issue.

I still don't understand the braking thing. The brakes are the same on the SWR as the DRW trucks unless a model change. I have never ever been able to lock up my rear wheels on my srw trucks while towing.

The DRW simply gives you more tire surface on the ground which translates into more braking surface,(twice as much surface).
In the end the additional tires provide better braking.

It's not a matter of locking up the tires but a matter of a shorter stopping distance.
Imagine if Fred Flinstone could have stopped using 4 feet vs. 2!

My point is that the brake pads, rotors and hydraulic system does not have enough power to make two wheels slide with a load on it so how is two more wheels going to make you stop faster? If anything, the two extra wheels and fenders is more weight to stop. :S

Like many things on the forum.
We calculate,figure,wonder,hypothesize and imagine but none of this is a substitute for actual experience.
We draw firm conclusions based on everything except actual experience.

I have towed the same 10K trailer with both a dually and a SRW truck. The DRW truck stops significantly better.

If in doubt get your hands on a dually and give it a real life trial.

Tankcar wrote:
Hi. Why are so interested in fuel mileage? You are towing another vehicle thats (dead weight). The higher you go less mileage you get.

Quite simple...my next truck is going to be a DD at 60-70 miles per day. 1-2 mpg doesn't sound like a lot but it does add up at this kind of mileage. And having a commuter car is generally false economy even at 30 mpgs. By the time you pay the payment , insurance, and gas and maintenance the commuter is a wash at best to a loss at worst. At least in my experience.

And I do not mind the diesel folks chiming in...all are welcome on this thread.

I could make the right Half ton work...but I'm not buying new and good HD trucks are plentiful HD half a are not.

Thanks,

Jeremiah