what do i set my tire pressure on a drop axle tire

I’ve noticed that some different brands respond differently to air pressures for a given load.

Also the number of plies makes a difference too.

Some 11R22.5’s on the drives I can put at 90 Psi and it wears perfectly even fully loaded.

Others I’ve noticed wear faster on the outside with pressures less than maximum on the sidewall. So these I run at 105-110 psi.

For the live bottom lift axle with 275 tires, I’ve got them at max of 130 psi as they’re always loaded when they’re down. The tandems (11r22.5) on the same trailer are at 110 psi.

The tridem stepdeck we have is only fully loaded 1/3 of the time and often times local. These 255 size tires we keep at 110-115 psi instead of 130.

 

There’s nothing wrong with starting at 130 psi.

As time goes on, watch how the tire wears.

The tread wear will tell you the best pressure.

If it wears in the center, like only 2/3 of the tread touches the road, then it’s too much. Try 120psi after.

It’s actually better having more pressure than not enough.

Not enough pressure causes excess heat which leads to tire failure.

A cooler tire doesn’t wear as fast as a hot tire too.

The live bottom is loaded with 36 metric tons everytime. Not 20 or 10 etc. Every load is 36 so the tire wears, how it squats according to that weight.

 

You mean the outer corners? Both outer corners on the same tire?

If the lift axle is perfectly aligned, then there is only center wear and outer wear on both sides of the same tire depending on tire pressure.

wear on both the outside corners of the same tire is under inflated. If it was too much pressure, the center of tread will wear more.

Unless your lift axle air bags are set at too much pressure causing excess weight on the lift axle.

 

That’s what going to the local scales will help with.

Sometimes it’s not possible for some people to be close to a scale.

I have access to material at our own yard which I can load the trailers with to max weight.

I’ll get the trailer fully loaded at our yard with sand or stone to legal weight and then set everything how it should be set up on each axle at a feed mill scale 2 blocks away. Then return to yard and dump the material back at the pile.

From then on, I use the suspension air pressure gauge to say when that’s it, it’s loaded. No more.

I do almost all the tire work at our company so I like looking at the tires whenever I’m doing my checks to see how they’re wearing and adjust accordingly.

Makes the boss happy.