Tyre pressure with Boyce wheels and HMMWW tyres

[superchicken]

Can anyone give me an idea of what pressure to run when airing down?
I've heard about 16.5" wheels popping a bead when lowering tyre pressure.
I'm leading a pack of over 150 Jeeps up the beach for topless day and figured a little preplanning could save loads of embarrassment.
Im running the boyce wheels and ex military 37" HMMWW tyres

Cheers T

[Barrman]

Most people have issues with the 16.5 tires below 12-15 psi. Don't go lower than that.

The 37" HMMWV tires are the radial version. You should get sidewall flex with the heavy M715 below 25 psi. The lower you go, the better the traction and smoother the ride.

I would suggest 20 psi and see how it does. If you are spinning and slipping away, drop down to 18 and see if it helps. Below that you are in the unknown zone so it will depend on weight, load, terrain and driving style mixed in with the psi.

[superchicken]

Much obliged Barmann, I'll go to 20psi and give her a go!

[jeeper]

I've never used the 16.5 tire/wheel combo at the sand dunes but I've driven on the sand dunes here in Michigan quite a bit. What I do know is 20 PSI does not generally work well in soft sand. You will dig yourself down to the frame in a hurry if you spin your tires. On my Jeep TJ with 33x12.5x15 inch tires I would run about 8 PSI. I could go most places in 2 wheel drive including some of the bigger hills.

I'm definitely not recommending you run your wheel/tire combo at 8 PSI. I'm just giving you a reference point. With 15 pounds on my same Jeep with the same tires I would dig in instead of float over the sand in 2wd. In 4wd (with 15PSI) I could still make it most places but the bigger hills required more speed/momentum.

If you are just staying on level sand you probably won't have a problem with 15 PSI.

[kwai]

Convert to the hummer wheels. the double beadlocks will allow you to air down as low as you want to go.