Why F-550 instead of F-450 chassis cab?

Why do medium duty, high end Expedition vehicles like EarthRoamer LTS start with an F-550 instead of an F-450 chassis cab? I thought the only difference between the two was the suspension but builders replace all the components anyway. What am I missing?
Thanks!
 

Buliwyf

Viking with a Hammer
F450's don't have the stoutest rear springs or the cargo rating of the 550.. More like an F350 DRW CC with 19.5" wheels and a bigger rear axle.

ER's are Greyhound bus heavy.
 
F450's don't have the stoutest rear springs or the cargo rating of the 550.. More like an F350 DRW CC with 19.5" wheels and a bigger rear axle.

ER's are Greyhound bus heavy.
EarthRoamer replaces the springs with kelderman air suspension. As far as I know, the F450 is otherwise the same. For legal reasons, it makes sense to start with a truck with a higher max GVWR. I was just wondering if there were any other mechanical differences.
 

Buliwyf

Viking with a Hammer
I could have sworn there's a bigger axle under the 550. The price jump online between 450/550 seems substantial.
 
I believe that the air springs are optional. An option I would forgo if planning on leaving North America.
I would imagine EarthRoamer would build your suspension however you want but the air suspension is what allows so much articulation. But I agree, it seems between the air suspension and ultra low sulfur diesel, EarthRoamers make more sense in North America.
 

Alloy

Active member
If the warranty on the powertrain wasn't coverd by FORD then EarthRoamer could do as they like.
 

Zybane

Member
F450's don't have the stoutest rear springs or the cargo rating of the 550.. More like an F350 DRW CC with 19.5" wheels and a bigger rear axle.

ER's are Greyhound bus heavy.
Uh, no. A MCI 102DL3 Greyhound bus is 35,100 lbs empty, GVWR 44,400 lbs OR 48,000 lbs.

EarthRoamer XV-LTS - 19,500 pound gross vehicle weight rating. Well under half the max weight of a Greyhound.
 

Buliwyf

Viking with a Hammer
That's cute. Maybe I should have used brackets to denote sarcasm, or been more obvious for special needs kids.

ER's are HMS Bismark heavy, up there with up armored LMTV's. [I'm sure that 25,000# should slide effortlessly across soft ground.]
 

cph05a

Member
ERs gvwr is 21,060lbs. I think they have Ford recertify it after all the suspension changes. Too heavy imo but I've never owned one.
 

lucilius

New member
To answer the OP: because ER's camper is a substantially heavy (some might say Bismarck or Tirpitz heavy) vehicle and it only makes sense to go with Ford's highest weight rating "pickup truck" design.
Depending on the year, the Dana 110 rear axle is rated to ~14k lbs. Most ER's have a rear axle weight in the 11.5-13.5k lbs range, loaded with 90 gallons fuel/90 gallons fresh water and don't forget the 300-400lbs of batteries, grey/black water tanks, real maple interior carpentry, and then all the good stuff you pack to take your trip, etc. The load on the front axle is going to be about 6k lbs. I suspect that like GVWR, the axle rating is based on at least a few design/system constants. In other words, the companies building axles and trucks set the weight rating of their gear and once a custom company or individual starts changing things, e.g. all of the ER modifications to the base F550, the "rating" probably changes as well but it takes a rare breed of dedicated individual to go through all of the trouble to get an OEM to certify an increased GVWR. I would think the standard loadout on a typical overland-expedition Toyota Taco heading out for week or two in the bush is probably exceeding the GVWR quite a bit...hence all of the suspension, wheel, tire, engine, etc. mods. Everyone seems to be doing fine.
 
I followed along on a 550 build ,when it came to the part where buddy said the single wheel set up weight was 300 lbs each and he had 6 with the spears .and a winch system to get them on the back of the truck . It through me off ,that is half the weight of my L200 Mitsubishi . if you berry one of these in the clay you will need a large piece of heavy equipment to get you out . But I am just another guy that can't afford one so easy to find fault . up where i am the MTO does not care what you add on to increase load carrying . they open the door read the sticker and that's it .
 
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