using a lift axle?

So what is the Max weight you can have on the tag/lift axle. Is it what ever the max load weight of both tires and less than 20,000lbs?

 

It depends on a lot of factors. What the axle is rated for, what the tires are rated for, the distance from the lift axle to the front or rear drive axle depending on weather its in front of or behind the drivers, what states you're running in and the reason for needing extra weigh carrying capacity.

 

I hated the need for lift axles when it came to towing and recovery, because you actually get screwed when it comes to how much the unit is rated to lift. The idea is to take 1/2 of your steer axle weight, then you multiply it by the wheelbase, then divide that number by the overhang. So, running a tandem wrecker, your wheelbase is measured from the center point of the steer axle to the center point between your drives. When you have a pusher axle, that rear measuring point shifts to the center of your first drive axle. Which, for a typical OTR truck, I was good either way, but it became a problem when you'd get into towing vocational trucks and such - which tended to have a lot more weight on their steer axles when laden. Going down the road with those, I'd have been actually been better off to run just a tandem, but the pusher became necessary because of weight limits.

 

"So what is the Max weight you can have on the tag/lift axle."

For the tag on the trailers it was max 8000 something, but safety guy said over 7500 was good. That's one tire each side. Only down when loaded.
Don't remember for pusher on tractor. Just went by pressure and hardly ever messed with it. As mentioned above, up/down in cab, pressure adjust outside cab. Down loaded, never, ever down empty. Ever.

 

my question again, what is the absolute maximum possible weight you can put on a tag axle. im aware you need to comply with the other factors, if this axle had tire that can have 10,000 lbs on both tires and there is 2,000 feet distance from the next axle, is 20,000 lbs the absolute max weight you can put on the tag axle.

 

If the axle is rated for it and the jurisdiction you are running in permits it then yes you can put that much weight on it. Hendrickson makes ones rated up to 22-25,000 pounds if I remember right.

 

However much you are willing to pay. If you are willing to pay some company to build a 100k axle, I'm sure someone will. Not legal on public roads sure, but mine operations do have some fairly large machinery around....

 

tractor trailor using my lift axel was easy then driving a mixxer the lift axel was set at a certain preasure but i adjusted my tag axel depending on the weight a yard of concrete weighs 4100 pounds roughly i would adjust my tag axel 200 pounds for every yard of concrete but now im driving 14 wheel and 16 wheel dumptrucks with drop axels and not sure what my correct pressure should be except dont want it so ihigh that i float my steer tires a 14 wheel hauling 18 tons what would be a close air pressure for each drop axel anyone know the answer or give me a preassure to start with

 

With quads and quints, I wanna say I ran about 35 - 40 psi.

 

The way I use my drop. Is just enough pressure to keep the drop from locking up when i need the brakes.

I'm not at my truck but I think it's around 30 or slightly better.

Keep in mind. The more pressure you add. The more weight you take off the steers and add to the drives. If you've got the typical front drop and not one that's behind the drives.

With my drop down. My steers are light enough. I don't need em lighter.
Some states might hassle you if not enough weight on the steers also. Oregon being one of them.

Easiest way to determine weight capacity for tri axles is to measure center of front axle to center of rear axle. That's called bridge. Look at your bridge weight for your state. You should have a table chart of how much weight can be hauled for how many axles and the feet length for the group of axles. If not. Google is your friend.

It's pretty uniform for the western states. Minus Oregon. They have a slight lower tolerance. And Cali/Az. My Tri allows the federal standard 43,500. But My axles are close together. Some trucks have the drop spaced out away from the drives. They can haul a little more.