What is the maximum possible, load a typical 18 wheeler can carry

While it is up to the state, in the northeast most states all for reducible (bulk/dump/etc) and non reducible permits (moving machines). My home state of mass allows for 99,000 on 5 axles and 77,000 on a triaxle, NY will allow 117,000 if you have 7 axles on the ground, (5 axles is 102)I have accidentally overloaded myself on occasion in NY by loading a 5 axle trailer like a 7 (on site only of course....) With the Tri axle low bed in MA I was good to 130,000. Hauling 80k for me is almost like running empty

Michigan is another one that runs heavy, I believe with 11 axles they can get 164k on them

 

Here in Alabama we run on 4 axles 82,500 on 5 axles 88,000 on 6 axles 92,400. This is NOT allowed on the interstate! There are other states that allow this as well like Florida, MS, and GA with the purchase of a yearly permit (cost varies state to state) and again you are NOT allowed on the interstates.
There is addition wear and tear on the trucks and trailers. Particularly wheel seals, bearings brakes and tires. Fuel cost is higher and preventive maintenance is even more important.

 

Let's toss the laws. Toss the charts. Let's have some fun.

1965 Mack short, two cycle engine 9 manual. About 270 horse at the fly wheel, god only knows how little is left at the drives. Add a 40 foot chassis and seacan. Load it to the red line at roughly estimated 160K in total gross weight.

Head to the port for ship loading the box. The performance of the rig got it to baltimore, but I never saw that tractor again, rumor had it that it was totaled not least due to frame damage, bearing glassed over and so on. One set of scales failed at 136500. That was all one state could write in a ticket on over gross. I think they replaced the platform cells with a bunch of money the ticket cannot even begin to pay. I was licensed with 99K gross, but that peice of paper flew in the face of laughing police.

Examining the interstate and certain specific routes. I tested the US 15 crossing at Tuscorora. It's a 5 bridge structure of Truss steel beams and concrete. It took the load. But rated in wartime for 200K. I crossed another bridge in a small river called Monacacy. This one does not exist anymore because it's been demo'ed. It was already schedule for demo when I crossed it. 3 weeks prior. It took the load but showed stress and noises.

This one load stands out in what is possible with a 5 axle truck. But it does NOT mean it's safe. Front end fails at 31 mph, brakes dont have all the air in the world to stop worth a #### so you planned it very carefully on the exact route in your mind long before you spent that air. Seeing 130 pounds PSI go to 30 and spring brakes kick in the help until the compressor got back to 55 or so it's fun. Not.

When you consider that the springs did not stop the heavy load.... That is where the additional damages began to accumulate.

Interstate bridges are rated for about 400,000 somewhere long ago for wartime purposes and not all of them will take that weight. I think most states will allow is something around 300000. On many axles. Considering im half that on 5 piddling axles with worn out container tires and rotted tractor tires.... Made 20 years ago at the time the load was moved in the late 80's

Fast forward to now.

I consider 100K a adequate weight for today's trucks. Toss in a axle or two under the drives if you must. Dump trucks do it all the time with tag axles that are lifted for turning or not loaded. Let's load em up.

 

If you spec the truck with axles and components built to handle those weights (23k steer, 58-65k rears, and 20-23k rated lifts), the maintenance won't be any more rigorous than running legal loads with a 12k steer axle and 38k drive axles. Try to cut costs with "bare minimum" specs and work them at 100% capacity, you'll pay for it in maintenance and repairs. Spend a little more and spec it to run at 70% max capacity, you'll save on maintenance and repairs.

 

My truck and trailer are spec'd to handle the weight. However there is a increase in operational cost simply because of the additional weight. There is no way around that.

 

I had a number of tractors spec'ed by fleet people in company headquarters who did not ever touch a big truck. Their job was to source tractors for the fleet at a good price to the fleet.

One example. Spicer 1300 pound feet drive shaft. Designed to fail if you applied more than that torque to it.

Sliding tandems at the first scale house on the interstate, that shaft twisted. SNAP. My mind filled with WTF that first time.

Then the yelling started. I defended myself pointing out that engine was able to source more torque depending on what I do to it hauling deadweight across the tandem slide rails back there.

Try to be cheap, your truck will break in creative ways.

 

I was referring to fuel cost, wear on tires etc. as being higher it simply cost more to move more weight.

 

Keep filling your trailer up with cargo when the springs and shock absorbers pop you'll know its reached its limit

 

You will hear creaking. Stop loading.

In fact the rig I talked about actually swayed side to side at the dock when I pulled away in low. I made it 5 feet as all of my drives leaned side to side on the creaking axles. I have never before or ever seen such flexing and crying out of steel and metal as those wheels leaned to one side then back to the other about 10 degrees from forward vertical.

 

Some of the loggers here do just that then they wonder why the DOT and portable scales are on their butts all the time.