Overloading a truck

[Welder Dave]

I was curious how much you could occassionally overload an off road dump truck at slower speeds? I know CM has way overloaded his Ford L9000 without issue. My L9000 has a 16K front axle and 40K rears with a double frame and dual steering boxes. I know if I put too much moist clay the hoist struggles on the third section. That kind of limits how much but I have no idea the weight. What would be a relatively safe overload? How much stronger is a double frame and what is the weak link?

 

[Coaldust]

In my world, I’ve noticed it being more of an issue with single axle rigs. The weak link is the front springs and spring hangers/ bushings. Then, occasionally, broken leafs in the rear.

 

[Deere500a]

Spent a couple yrs driving Cali 70k super dumps 20k front 40k rears 12k pusher mixer spec trucks held up sold pass couple owners clutch not so much early 2000s truck were under built 8.3 or C10/c9 carrie 21tons later trucks engine upgrades,airride haul 20 tons poor truck lift the axle on site truck would grown but held up hard to over load 10wheel box specs would hurt it I'd get stuck overloaded doing off site work with super because box size boss was ok with odds truck will be fine

 

[cfherrman]

On a 3 axle truck if you still can use your brakes without smoking them you are probably fine

 

[Truck Shop]

The older the truck the more fatigue areas show with overloading. It all has to do with
how many times suspension/frame is cycled from laden to unladen, along with any
corrosion around frame/suspension fasteners/brackets.
*
One area that is often overlooked is rear axle housing suspension hangers. With Hendrickson
RT or RT Extended leaf off road overloading really stresses the axle housings at point
of beam hangers. I have seen several that are damp/slightly moist from 75x90 leaking
through hairline cracks next too hangers, and some that have broke to the point the
crack is 1/2" wide. Which is replace housing. Depending on specs when built depends on
specified housing used when built, because there are different thickness of housings.
Most are 3/8" to 7/16 standard, then for heavy use 1/2" plus thick.
*
The other is frames cracking horizontally from suspension/crossmember mounting holes
started by too many frame twist cycles and a slight bit of corrosion. Frames don't always
crack vertically. Trouble with lined frame rails is just how much unseen rot between rails.
And lined rails do crack now and again. But the big thing is just how much a person
thinks they saved by overloading each day verses a unusable truck.
*
Housings on air ride will crack also, but not where one would expect. Right on top
where rear cover bowl is welded to housing. Those can crack 12" long across the radius
on top and sometimes on bottom. Next is rims cracking at mounting holes. The list
is long.

 

[Deere500a]

Failure is hours not miles. How many hours til auction low mileage

 

[cuttin edge]

One company i worked for had tandems hauling with rock trucks. Material falling off the front back and both sides. You would haul like that every load, every day all summer. Mind you they were R model macks

 

[MG84]

If you are getting to the point the hoist wont lift it, you're probably way beyond what is safe for the truck.

 

[Truck Shop]

Failure is also poor design and arrogance-for example, Oceangate sub Titan.
*
When a cylinder fails with a load of wet material, it makes for a swaybacked mule.

 

[IceHole]

If you are getting to the point the hoist wont lift it, you're probably way beyond what is safe for the truck.

Or weak hydraulics.

I had to shim the relief on a truck. I had, wouldn't lift 10 yards beyond 1st stage of cylinders, sometimes could do 2nd, but not 3rd (twin cylinder).
Was only making 1800 psi. I set it to 2300 i think and no troubles after that.. hard mounted a gauge in the cab to keep an eye on it too.

The hoist on my F350, they hooked the lines backward so up relief was like 750psi and down 3000.
Took me a bit to figure that one.
First time I went to dump it was a load of logs and I figured must be heavier than I thought, or hopefilly not... this new $$ hoist is crap..

 

[Welder Dave]

I don't think I've severely overloaded it. It has a low side lighter duty box. I think the relief on the pump could be turned up a bit but it also tells me when it's a little heavy. Being it's a continuous pump with a solenoid valve, the hoist is one speed and doesn't seem to change with higher RPM's. However when lowering you can't slow it down. With a full box that doesn't lift it comes down way too fast and I worry I'll blow the cylinder apart. Probably a good thing the hoist tells me when it's too full. I was just curious how much safety factor there is and how much stronger is a double frame over a single? They don't use a lot of salt here and I don't see signs of rust jacking.

 

[cuttin edge]

I don't think I've severely overloaded it. It has a low side lighter duty box. I think the relief on the pump could be turned up a bit but it also tells me when it's a little heavy. Being it's a continuous pump with a solenoid valve, the hoist is one speed and doesn't seem to change with higher RPM's. However when lowering you can't slow it down. With a full box that doesn't lift it comes down way too fast and I worry I'll blow the cylinder apart. Probably a good thing the hoist tells me when it's too full. I was just curious how much safety factor there is and how much stronger is a double frame over a single? They don't use a lot of salt here and I don't see signs of rust jacking.

Hauling asphalt sometimes requires taking a small amount off a full load. Maybe a driveway that needs a couple wheel barrow loads in an apron. Asphalt especially a full load will hold together then it breaks. The load is tarped so it's dark in there. Somebody dumps the truck and when it starts to come the driver has to react fast to the dump man saying down. Let me tell you when you are up almost a full segment, 15 metric tons of asphalt slams down on a frame some hard. There is a girl with a you tube channel. She drives a dump truck with a pup. She has an electric valve for the talegate. The air valve is at the back. She had the box up full load. Put the safety prop up. Would never stop a falling box. She climbs up on the frame under the loaded box to manually trip the gate. She needs her arse kicked. Made me sick just watching

 

[OzDozer]

Most equipment has 100% overload engineered in. But if you haul overloads regularly, you shorten the lifespan of your rig.
Seen so many older trucks from WW2 era and post WW2, IH's and Fords, with bent chassis rails behind the cab.
They jacked them up and plated them with big fishplates, and went on overloading them! - and they still ran for many decades after.
I always recall the old newspaper advertisement from just before WW2, that the brother and I found under the floor of an old prospectors hut we demolished.
It read, "For sale. 1935 Chev 1-ton utility (pickup). Good condition. Will carry 2 ton!"

 

[IceHole]

Hauling asphalt sometimes requires taking a small amount off a full load. Maybe a driveway that needs a couple wheel barrow loads in an apron. Asphalt especially a full load will hold together then it breaks. The load is tarped so it's dark in there. Somebody dumps the truck and when it starts to come the driver has to react fast to the dump man saying down. Let me tell you when you are up almost a full segment, 15 metric tons of asphalt slams down on a frame some hard. There is a girl with a you tube channel. She drives a dump truck with a pup. She has an electric valve for the talegate. The air valve is at the back. She had the box up full load. Put the safety prop up. Would never stop a falling box. She climbs up on the frame under the loaded box to manually trip the gate. She needs her arse kicked. Made me sick just watching

I saw that. Was confused what she was doing. I barely trust prop rods empty... to the point I generally add extra or a 4x4 across the frame near the hindge.

 

[cfherrman]

Lots of military stuff had different ratings for slow speeds too.

If you are driving private roads or off road and you can use the engine to slow it down, means you are not going that fast, you are good. If you gotta use a lot of brakes your are probably too heavy

 

[Truck Shop]

Yeah it's all good, till suddenly it isn't, for every action there is a direct and opposite reaction.

 

[cuttin edge]

I saw that. Was confused what she was doing. I barely trust prop rods empty... to the point I generally add extra or a 4x4 across the frame near the hindge.

Any truck I've ever driven has the air talegate control in the cab unless it's a dump trailer then it's electric. But at least the override valve is on a box outside the frame, not under the box

 

[IceHole]

Most equipment has 100% overload engineered in. But if you haul overloads regularly, you shorten the lifespan of your rig.
Seen so many older trucks from WW2 era and post WW2, IH's and Fords, with bent chassis rails behind the cab.
They jacked them up and plated them with big fishplates, and went on overloading them! - and they still ran for many decades after.
I always recall the old newspaper advertisement from just before WW2, that the brother and I found under the floor of an old prospectors hut we demolished.
It read, "For sale. 1935 Chev 1-ton utility (pickup). Good condition. Will carry 2 ton!"

I carry 5 tons in 1 ton. Been doing it for years.

 

[Welder Dave]

10,000lbs GVW for a 1 ton was pretty common back in the day. Today it's even higher. I had a 2500 with an 8600 GVW 3/4 ton.

 

[smifwal]

Roofers round here upgrade ram but nothing else on the dump trailer, so they call jail more and be unsafe