2008 F-350 or F-450 DRW or SRW?

[M&S Norrell]

We are not fulltimers; more like one 3-4 day weekend each month. We currently have 2000 F-350 SRW Crew cab 4x4 w/ 3.73 gears and are ready to upgrade. Dealers making all kind or promises on gas mileage etc. Is there a difference between F-350 & F-450 driving (w/o the rig on back) gas mileage? What will that 4.30 or 4.10 or 4.88 do to mileage. We'd still like to keep the crew cab for the extra space. Our unit is the 2007 35MKE so I think its about 14K maybe 15K when we load everything up. Then again there is the new Dodge, but not sure about towing capacity. Upgraded the hitch to Reese 17.5K already. One dealer said F-450 had larger wheels so the traveled further on single rotation; thereby saving on gas???

[CD]

M&S Norrell
I would go with the F450 size and duals. You have a lot of trailer for a 1ton. I wouldn't pick gear ratio just for milage. I did that with my first '01. I got the 3:54 and to keep from lugging the engine you had to drive 65/70. After totaling it I got another one just like it except the 4:10 gears. I liked it much better and only lost about 1/2 mpg. I didn't buy the 6 speed for an overdrive.

[jperry29]

The F-450 can, and probably will, have a longer wheel base than your F-350. The frame and suspension are definitely heavier and stiffer. While your F-350 weighs between 6 & 7 thousand pounds, the F-450 will start pushing 9,000.

Even if the gear ratios are the same (and despite the claim associated with the 19.5" wheels), the simple physics of getting that much extra weight moving means your mileage is going to be less in the F-450. How much less depends on your driving routine. If you have to do a lot of stop-and-go, you are really going to notice a difference. If you spend lots of time at highway speeds, then not so much.

The ride, loaded or unloaded, in the F-450 is stiffer. But I have to tell you, having the heavier frame and suspension and bigger brakes once hooked up to all that weight makes it worth it to me (I changed from an F-250 to an F-550 in '06). If those weights on your trailer are right you are surely bumping the maximum capacity of an F-350. Running at or above maximum rating is generally a quick way to wear out a really expensive vehicle.

I have the 6.0L and 4.88 gears. Regardless of which gear set, loaded or unloaded, the "sweet spot" for fuel economy is 2000rpm for the 6.0. Unfortunately that translates into about 53mph for my rig. Of course I can go faster but fuel economy drops rapidly for every 100rpm that I add. I would expect that the new twin turbo 6.4's would be about the same.

[Rick A]

I have read numerous complaints on dieselstop.com about the fuel mileage being noticably worse on the new 6.4 because of the new emmissions. Looking at the brochure a F-350 DRW 4X4 with 4.10 is rated for 5th wheel towing at 15,200. If you are correct on your trailer weights, then I think that would be too close. Move up to 4:30 and that gets you 17,700 which should be plenty. If you go to F-450, lowest rating is 20,000 so no problem with either 4:30 or 4:88. It soesn't look like anything in SRW is going to have enough towing capacity for your trailer. So it look like you are looking at DRW with 4:30 or 4:88. My preference would be F-350 w/ 4:30 for ride and fuel efficiency.

[K-Star]

with my old F-250 (7.3l) and 3.73 gears I averaged around 12 pulling the trailer and 18-19 solo. With my new truck (6.0 with 4:30's) I get around 16 solo and 10 towing. The lower the gear (higher number = lower gear) the less MPG you will get as the rpm's are higher.

I haven't compared the F-450 to the F-350 spec's so I don't know if the F-450 is longer or not. I recall a time when I was spec'ing an F-450 using the Ford commercial truck website, there were a choice of wheelbases. Spec'ing an F-450 now, wheelbase is not an choice.

I agree that going to a DRW is the better option for two reasons. Increased payload and more stability when towing. Additionally, the F-450 will give you more flexibilty if you ever decide to replace your current trailer. But how often do we RV'ers ever think of upgrading their rig????

[RustyJC]

In response to your original question, a DRW truck is highly recommended for pulling a heavy 5th wheel. Since a 5th wheel transfers ~20% or more of its weight to the truck as pin weight, a SRW truck will invariably exceed its GVWR long before it reaches its "manufacturer's trailer tow rating" in a 5th wheel application.

The "gotcha" clause in the brochures that cite the manufacturer's trailer tow ratings is buried in the fine print with a statement similar to "None of the truck's other ratings are to be exceeded when towing."

Rusty

[TXiceman]

Like Rusty noted....read all of the fine print...that is where they bury the gotcha.

The truck tow ratings are based on a stripped base model truck to minimize curb weight and maximize towing rating. A lighter weight SRW truck will have a higher tow rating, but the payload capacity will be the problem. Look at the GVWR sticker and rear axle GAWR on the B pillar tag on the truck.

A typical 5er will carry close to 20% of the trailers GVWR on the pin. So if you look at a trailer with GVWR of 15000#, you can expect a loaded pin weigh of close to 3000#.

As an example, we have a 14,400# GVWR 5er and a 1 ton dually with a GVWR or 11500#. I have a loaded pin weight of almost 3000#. The truck weights 8000#, fully loaded, full fuel and hitch. So I have a actual payload capacity of 3500#, only 500# above my ready to travel load.

No way I could be in ratings with a SRW truck.

So what dictates the use of SRW vs. DRW is the trailer pin weight and the real world payload capacity of the truck.

Ken

[Ray,IN]

If I were shopping for a Ford F450, hereis where I'd spend some time. These prices are the same-or lower- than for a F350 locally.

That blarny about larger wheel turning slower and getting better mileage- . It it were true these MH guys driving on 22.5" tires must be getting fantastic mileage.

[Rick A]

The 2008 F-450 is the same dimensions as the F-350. They are both using the same cab and bed. The differences are larger tires, brakes, and heavier suspension.

[Dieselgem]

M&S

I have the 2008 F450 and it is a great towing machine. The suspension is great and the brakes are huge. It is however made for towing heavier loads and not geared for the best MPG. There are a lot of posts on the dieselstop forum regarding this issue.

[powerboatr]

Quote:

Originally posted by Rick A: The 2008 F-450 is the same dimensions as the F-350. They are both using the same cab and bed. The differences are larger tires, brakes, and heavier suspension.

acyually the new 450 pickup is a hybrid it combines the 450 frnt frame on a 350 rear frame, it gets a wider frint wheel track that get closer the matching the rear wheels outer track.

we have a 4.30 in our 350 tow boss, our sweet spt for POWER in my 6.0 is 2200 rpm nets us 12-13 towing
15-16 empty
2000 rpm is good but lugs to much with the trailer in tow and will dwn shift to much

this being said i am switching to 22.5 wheels now to to get better MPG LOL thats a good un

if we were to go new the 450 would be a serious contender as would a retired class 8
but now with registration fees not to my liking i may switch to a DP

[NeFlaGuy]

We purchased the new F450 (6.4L) 4.88 and with a little sly of 5,000 miles are currently getting an average of 11 mpg. The turning radius is out standing. We have not had any problems what so ever in these first 5,000 miles. This is all without towing. We will be taking delivery of our new NuWa in the first part of Oct.

[Hitchhiker]

Quote:

Originally posted by NeFlaGuy: We will be taking delivery of our new NuWa in the first part of Oct.

Lou,

Welcome to iRV2, we're really glad to have you here as a new member and are looking forward to reading your posts about your experiences and adventures in your new F450 and also with the new HitchHiker Champagne 37CKRD you have on order. That's the identical trailer I have.

You'll find a great bunch of folks on this site who are very knowledgeable of RVing, , just as you've found over on the NuWa Owners Forums. As you'll soon see, they're eager to help and share their knowledge and experiences with others.

Again, welcome to iRV2, we're glad you joined.

[M&S Norrell]

Dieselgem - Saw the truck pics - looks just like ours EXCEPT...where did you get the running boards? Ours came witht the tubular ones and there is just not enough tread for my liking. Also, I saw you had the transfer flow gas tank. I am looking at the Transfer flow 60 gallon replacement tank. Hoping someone will work out how to hack the onboard computer so the miles to empty etc. works correctly - not detrimental though, I can still read my gas guage.
How much does your unit weigh (also what is pin weight)? Our Excel 35MKE squats our truck more than we were expecting! (15K w/3200# pin). We have the Reese signature series 18K hitch with TrailAir Hitch Pin, and at the lowest settings our rig still rides a little high in the front. We have about 7" between bed and 5th wheel tongue. How about you? 400 mile trip w/ less than 1000 miles on truck netted us 7.4mpg; hopefully that will improve somewhat