E350/450 Cab-Chassis w/ Composite Box Body - Feedback Requested

[luthj]

Hey gents, I am planning to build a 84" wide by ~14ft composite box on a chassis. GVW in the 11klb range. Considering medium duty cab over engine trucks and vans.

The intent is for full-time occupation for years at a time, and will be used for international travel. I like the E-series due to the gas powerplant, and option for reliable 4x4 (UJOR etc).

I am looking for some feedback on the E-series, as I am not intimately familiar with the platform. I know this is the van sub-forum, but there is probably more E-series experience here in general.


Track width, wheels etc:

Looks like the E350 SRW (cab chassis) has a hub-hub width of about 73"? Confirmation would be great though.

Typical 4x4 swap front axles are about 70" hub-hub width?

Looks like method 17" wheels with zero offset are a readily available option. (single rear wheels are a requirement for us).

Axle loads:
Any issue running 4,500-5000lb front axle load with a D60? No chassis issues with that weight?

General Questions:
Issues with the 7.3l gas and 6 speed trans? Anything to be aware of?

Fuel economy expectations with 35" tires, 4x4, and 84" wide by ~89" tall box? I see some small class Cs in the 11-12 range with conservative driving. Seems high with the 7.3L, but that's just a gut feeling.



Anyways, I will dig through the thread archives as I have time, but any useful links/threads would be greatly appreciated!

 

[RVflyfish]

Two of my favorites…

Calgary McLean’s

PathNotTaken’s

 

[iggi]

The width of the Econoline is narrower than the F series so this seems wrong: "Looks like the E350 SRW (cab chassis) has a hub-hub width of about 73"

I still had a tab open from looking up axle widths a few days ago:
The hub-to-hub width for a 2005 Ford F-350 Dana 60 is approximately 69.8 inches, with the WMS-to-WMS (wheel mounting surface to wheel mounting surface) measurement being 72 inches.

My annual average fuel economy is about 14mpg.
As a point of comparison, I'm coming in about 10,000 lbs, 2WD, 32" tires and a 6.0 Powerstroke.

I'm six years with my E350. Other than how much of a PITA it is to work on the engine it's been great.

 

[luthj]

The width of the Econoline is narrower than the F series so this seems wrong: "Looks like the E350 SRW (cab chassis) has a hub-hub width of about 73"

I meant to put "rear" axle in there. As the SRW cab-chassis has a wider rear track than the vans, with the DRW being even wider I believe. (75"?) The SRW is a bit harder to calculate the hub-hub distance due to the offset, but factory wheels being about 10-15mm, puts its around 73".

 

[luthj]

Did some weight distribution math, looks like my planned 14ft box will just work weight wise. This includes the weight of a 4x4 conversion, and 34" wheels and tires, plus water, food, passengers etc. Load range F tire is good for 7940lb, so there is a bit of margin. I would like a touch more weight on the front axle, but there isn't much to be done with a 158"WB and a longer box.

 

[Blackdogvan]

Best single tire options I've found is the Toyo Mud Terrain 37X13.50R17LT - 4300lb rated. It's a bit of a unicorn in the LT tire world but quite a few other options around 4000lbs.

You might check out Mesa Overland who is building a E350 from U-Joint at this time for inspiration on your build.

I think 4x4 converted they are a really great option due to their payload capacity.

 

[luthj]

I do see some 35s with ~3700lb load ratings. A few choices in the 37" range with ~4,000lb load range. I think 3,900lb should be fine with a decent margin.

Toyo does offer a the Open Country R/T Trail in 295/70R16 with 3,970. Which seems like a decent choice, and isn't lifting the vehicle to the moon.

I am curious about ride quality with UJOR conversions. I know its not going to ride like an IFS coil spring setup, but I don't want to hate myself after a 3 hour drive either.

 

[ujoint]

I do see some 35s with ~3700lb load ratings. A few choices in the 37" range with ~4,000lb load range. I think 3,900lb should be fine with a decent margin.

Toyo does offer a the Open Country R/T Trail in 295/70R16 with 3,970. Which seems like a decent choice, and isn't lifting the vehicle to the moon.

I am curious about ride quality with UJOR conversions. I know its not going to ride like an IFS coil spring setup, but I don't want to hate myself after a 3 hour drive either.

Come for a ride at one of our shops.

 

[luthj]

Thanks for the offer. Closest to me is CO (11 hour drive). If I end up that way I will drop by!

 

[luthj]

Looks like the E350 158WB SRW uses an oddball rear axle with a ring gear offset incompatible with locker options? Unfortunate if that is the case. I can't find for sure confirmation, as most of the prior results on the web are for the vans, not the cab-chassis.