I've been looking at used 350-550 trucks, either flatbed, flatbed dump, or just dump. I've noticed a few things when it comes to these trucks. Depending on the wheelbase there are different cab to axle measurements. Some place the wheels directly under the midline of the dump body whereas others are placed more towards the rear of the truck.

Advantages/Disadvantagea to either?

 

If the axle is further aft under the dump body (shorter axle center line to end of frame distance, hereinafter shortened to "AF", with longer end of cab to centerline of axle distance, hereinafter shortened to "CA"), then the advantage is that when the dump body is raised for dumping, the truck chassis will offer slightly more counter ballast to the entire truck flipping backwards with the load.

However, the disadvantage with shorter AFs and longer CA's is that more of the dump body, and it's contents, is borne by the front axle when the truck is traveling underway loaded. In fact, the front axle weight ratings could be exceeded.

On the other hand, a shorter CA and longer AF seeks to bias the load on the rear axle, which has twice the number of tires, over twice the axle rating, and bears only half the chassis weight with the body but without the load, and only 1/4 the bare chassis weight without the body or the load. For a dramatic visualization, picture how class C front engine motor home axles are typically arranged, where the rear axle sits practically in the middle of the house, rather than at the tail end.

The disadvantage in a dump body is that the farther forward the rear axle is positioned under the dump, the more weight gets shifted aft of axle when the dump body is raised. The dangers of that need no explanation.

That's why Ford issues guidelines for what length and type of body to mount on which CA distance, wheelbase, and cab option they offer. If you are shopping for a completed dump truck, then more than likely the homework was already done and the correct length body was matched by the upfitter to the appropriate length chassis and CA.

However, if you are shopping for a bare chassis cab and plan to mount your own dump body (or dumping flat bed... which still shall be called "dump truck" for purposes of this discussion, due to the weight shift when tilting back) then Ford's general guidelines are as follows...

60" CA good for 8ft and 9ft dumps

84" CA good for 8ft dump with a fixed cross bed full height tool box behind cab, called a "back pack", as well as 10 ft dumps.

For the F-350-450-550 chassis cabs you are considering, no dump body longer than 10 ft is recommended.

There are further limitations to the foregoing based on the cab type (regular, super, or crew) as well as the GVWR (F-350, F-450, or F-550).

Generally speaking, the F-550 has no cab style or wheel based limitations, except that the Crew Cab 200"WB/84"CA does not recommend the 8ft BackPack, however the 10ft dump is recommended.

On the other hand, the F-350 chassis cab restricts 10ft dump bodies (on the 84" CA) to ONLY regular cabs. The 350 crew cabs and super cabs are limited to only 8ft and 9ft dump bodies.

 

Great info. Thanks!

I would definitely like to be looking into the 550 (~19k GVWR) as after a 350 (~13k GVWR) is fitted with a body there is not much payload left.

 

Don't rule out the F-650, or better yet, the Freightliner M2-106 family, for more robust underpinnings on a single axle dump truck that still stop on juice brakes and still remain under the 26K GVWR limit before a commercial driver's license is required.

There is a HUGE functional and operational difference in haulable material weight capacity between 19.5K GVWR chassis and a 26K GVWR capacity. That last 3 tons of gross capacity can be applied purely to payload, as the difference in tare weight between a light medium chassis and a true medium chassis is incremental, while the weight carrying capacity is monumental.

Example: A completed F-550 dump bed, full of fuel, hydraulic fluid and mechanisms, tools and a driver, but no dirt, might weigh 11,000 lbs "empty". So it can carry 4 ton in material. By contrast, completed F-650 dump bed might weigh 12,500 empty. The cab weight is the same, but the tires are heavier, the axles are heavier, the frame steel is heavier, the exhaust system is heavier etc. So we've added literally almost "a ton" more chassis weight. But we gain two to three times that added chassis weight in additional carrying capacity, for a total of 7 tons of material hauling capacity in the F-650, which is 3 more tons over the F-550's 4 ton hauling capacity.

 

I don't have the money for it but this would be the route I would rather do.

This guy builds these with used freightliner trucks, switch n go bodies, and large tool storage.

He makes the same point about a truly heavy duty truck.

He puts these together for around $35-$45k

 

I have a 2012 F450 CC with a 12' stake body dump. Your right about the weight limits. I think I can carry 4,000 lbs and that might be pushing it. If I had it to do over again, I would go with a 550. I was told to stay away from 650's and such due to brakes and other parts are much more expensive, but if you need the GVWR thats more important. As to where the wheels are, remember if you tow anything, the shorter CA #'s makes for uncomfortable ride. I tried to find my CA # but it's at another location. Can look it up if you really want to know.

 

Cabindoc, your CA is 84".

You can confirm it yourself by looking at the fed cert sticker at the bottom of your B pillar door jamb. It may not say the CA distance, but it will say 200.2" wheelbase, which with a crew cab, means 84" CA.

 

That's a great truck! I think the payload sticker on my dually pickup is 4995lbs. That's the only problem with the lighter duty CC trucks. Start adding the body and all the other things needed and the payload goes out the window. Towing is a must so I can see what you are saying with the CA.

 

The same guy who uses those freightliners has this truck for his non hardscape work, so more of what I would be doing. Sorry about the Dodge but it's the setup that is great. Dumping flatbed with removable sides, custom tool storage, and the best feature, a side loading hydraulic ramp. The truck and mods were $$$ but I'm sure wasn't a big hit to his bottom line.

 

That body was custom built by my local Redding dealer. I think it was $10k. Like anything, it it's nice and custom, it's gonna co$t.

 

Absolutely!

In my landscape forum many say that custom trucks are the way to go for efficiency and I couldn't agree more. I tow my dump trailer with my dually and it works well but is a real pain as I need to load and unload everything all the time
But I still need the dually for the 5th wheel so I would like to get another truck to serve me better. If not this year maybe next.

 

Here us the truck in it's current configuration. I can take the boxes off in an hour and put the gates back on if I really needed to.

 

Scott... something in one of your photos caught my eye.





We have the exact same electrical connection box, mounted in the exact same location in the center of the rear cross member after the fuel tank. And what is weird about it is, that box isn't a Ford box, it is aftermarket. And we are on opposites sides of the country.

I found my electrical box by a stroke of luck 16 years ago, sitting on a dusty shelf of an old speed shop, and it looked like it would fit the bill perfectly (Chassis cabs don't come with towing harness connectors, just blunt cut wires). So it is strange to see the exact same box on another truck, and I would have to assume that Reading uses these routinely.

The body builders I've interacted with (Royal, Harbor, Fontaine, Scelzi, North Bay, and Daily) don't use these particular boxes, and some of the aforementioned builders don't bother with junction boxes at all.

I can't show a photo of where mine is mounted, because I have a piece of stainless covering that back area, but I do have a photo of how I wired the inside:



.

 

I really like the idea of a dumping flatbed or the landscape bodies that have a side door on them for the flexibility of side loading or being able to "split load" the bed. Much more versatility than a traditional mason dump bed. Especially with the type of work I do.

Ever use the dump while the tool boxes are attached?

 

ALL THE TIME

Y2K, so funny about the box. I found that box at an auto swap meet a year ago. It was all dusty. Just last week, I installed it when I changed the back up horn as a way to hide all the connections. My trailer wire connections are all bundled and taped in a thick cord.