Airring Down Commercial Bead Tires?

[tmckenna13]

My current "big rig" chassis has 10x285.75mm wheels on it. Currently planning on doing "floater" front wheels with a 385/65r22.5 tire. My question is, for soft sand what are the "rules" for airring down? I know in theory the profile of commercial truck tires is more likely to de-bead at lower pressures but I'm curious what kind of personal experience people have. (I have an SUV I drive on soft sand beaches and air down to 12psi and it drives amazing. I know commercial truck tires cant be airred down that low, thats why Im asking here)

 

[tbone1004]

I'd be concerned going lower than 80psi or so on them since there is no safety bead, I know some will go to 40psi if you're careful about sharp steering angles. A lot of it will depend on the actual front axle weight though.

 

[Peter_n_Margaret]

This is well below the yellow line to get over a particularly soft dune.

Cheers,
Peter
OKA196 motorhome

 

[tbone1004]

View attachment 875488
This is well below the yellow line to get over a particularly soft dune.
View attachment 875489
Cheers,
Peter
OKA196 motorhome

unfortunately the beads on 19.5 tires are very different than 22.5's which do not take airing down nearly as well

 

[Joe917]

I regularly dropped our 315 80 22.5s to 60 psi, never an issue. 9400kg.

 

[tmckenna13]

I regularly dropped our 315 80 22.5s to 60 psi, never an issue. 9400kg.

Do you start seeing the "pancaking" of the tire around that pressure? I have zero experience with commercial truck tires so Im just trying to get some real life info about best practices.

 

[tmckenna13]

I'd be concerned going lower than 80psi or so on them since there is no safety bead, I know some will go to 40psi if you're careful about sharp steering angles. A lot of it will depend on the actual front axle weight though.

I should be well below the total capacity of the tires. I have a friend with a 4x4 international 7400 that tows a huge fifth wheel on the same beaches I drive on. He says he airs his 22.5 tires down into the 20s and has never had an issue.

 

[Hotshotliving]

I should be well below the total capacity of the tires. I have a friend with a 4x4 international 7400 that tows a huge fifth wheel on the same beaches I drive on. He says he airs his 22.5 tires down into the 20s and has never had an issue.

Really? I have an international 7400 and I also run mine at 80psi all around all the time. I am concerned about airing them down though for that same fear. Is there a calculation for total weight vs total acceptable tire pressure. Obviously I wouldn’t be running anything less the 80psi while driving.