A trivial question about axles

[Carburetorless]

If a truck has dual rear axles, as opposed to a single rear axle, does that double the amount of weight it can haul over a surface, or is the added hauling capability more or less than double?

 

[farmboss45]

If a truck has dual rear axles, as opposed to a single rear axle, does that double the amount of weight it can haul over a surface, or is the added hauling capability more or less than double?

It does not "double", but does add to the weight rating of the vehicle. The suspension has a weight rating as well as the axle's. Just as the dual verses single tires. The more axles, the more weight can be hauled do to the weight being spread out on more area.

 

[Driver625]

Hauling capacity depends on the axle weight rating, gross vehicle weight, tire weight capacity, road weight restrictions, permits, yada yada yada, blah blah blah. There's a lot of variables that determine hauling capacity not just the amount of axles.

 

[madhatte]

This trick doesn't always work:

 

[Carburetorless]

This trick doesn't always work:

Lol, I'm asking for weights and measures, and you're giving me Guns & Roses.

 

[farmboss45]

.....well you were asking about duel Axles.

from the looks of that axle, your going to need a lot of them to haul anything!

 

[spindrift7mm]

axle ratings vary but an example 20,000 per axle 36,000 on tandems but spread like 4ft and your back to 20,000 per axle or 40,000 per spread tandems. this is in lbs.
oh steering axle is less 18,000 per in this example with gross wt being 80,000 in most areas depending on state and local regs hope this helps Ken

 

[northmanlogging]

the old military deuce and a half trucks had tandem rears or dual rears. but they only had a 5000 lb rating because they were meant more for flotation on soft ground than just balls out load capacity.

So in other words it depends on the truck, suspension, tires, engine hp/torque, transmission, all these things effect in the end what is safe to load on one rig.

 

[Carburetorless]

the old military deuce and a half trucks had tandem rears or dual rears. but they only had a 5000 lb rating because they were meant more for flotation on soft ground than just balls out load capacity.

So in other words it depends on the truck, suspension, tires, engine hp/torque, transmission, all these things effect in the end what is safe to load on one rig.

I see what you're saying. I'm mostly interested in the effect it has the surface the wheels run over. For example; If a single axle truck can cross a surface with 25,000 gross weight without sinking in, then how heavy can a dual axle truck be on the same surface without sinking in?

 

[northmanlogging]

That there is just too many variables to really give a solid answer, but dual axles, with dual tires will help, just couldn't say how much... Also gigantic tires help with flotation as well...

 

[Carburetorless]

That there is just too many variables to really give a solid answer, but dual axles, with dual tires will help, just couldn't say how much... Also gigantic tires help with flotation as well...

I was thinking along the same lines. I'm going to start searching google for a formula that will show me the exact numbers.

 

[redprospector]

Lol, I'm asking for weights and measures, and you're giving me Guns & Roses.

Hahaha. Ok, now I understand.
I was trying to figure out who was the flat chested little girl with all the tattoo's.
I never was into rock & roll that much so that one went over my head.

Andy

 

[StihlKiwi]

I was thinking along the same lines. I'm going to start searching google for a formula that will show me the exact numbers.

Try googling ESA (equivalent standard axles) and California Bearing Ratio

 

[OlympicYJ]

I see what you're saying. I'm mostly interested in the effect it has the surface the wheels run over. For example; If a single axle truck can cross a surface with 25,000 gross weight without sinking in, then how heavy can a dual axle truck be on the same surface without sinking in?

If I understand right you're asking about flotation? That would mostly have to do with contact patch of the tires, ie surface area of tires in contact with the ground. Then the gross weight of the vehicle to get a pounds per square inch. Any change in tire contact patch size would affect this.

It's not quite the same as the bridge formula the DOT uses to rate the weight trucks can haul which has to do with the spacing of the axles the rated weight of the axles and the tire size, in general, I don't know all of the inputs into the formula. Lowboys typically have a wide set of tires on the front because the larger contact patch allows them to haul additional weight on the front end. Trucks are allowed only so much weight on each set of axles: front, dop, rear drivers, and trailer axles.

Adding another set of tires will increase your flotation but if you add more weight it will decrease the overall gain.