BT17R

Access to my favorite 19 mile beach drive has about 150 yds. of soft stuff to negotiate before the hardpack. I usually just get up some speed at the start and float across it with throttle. However, the fun is exploring around the dunes = soft stuff where I tend to dig in and sink. I aired down to 28, but it didn't help much. How low should I go? I've the stock Dunlop Grandtrek AT20 265/65-17's. TIA...

partszar

My fist try would probably be somewhere in the 18-20psi range. The lowest I would try 10-15 psi. You would have to air back up before any street driving though. HTH

YoungFeller

You'll probably want to take them down past 28 for deep sand. 28 is more air than I usually run on the street. Take 'em down to 10 or 15 and go wallow!

Eric

Robinhood150

28 is way too high. Go down to about 10psi front and back. If you still find yourself getting stuck, go down even lower to about 8. The lower you go, the more you run the risk of breaking the bead so take it slow and don't turn sharp. Make sure you use a good pressure gauge, the normal ones you get from the auto parts store are junk and aren't accurate enough, especially at low pressure.

My friend routinely goes down to about 4psi at pismo, but he has some pretty good skills.

Steve

2wheeler97

I have a friend that went to pismo too, he aired down too about 8 psi, and the tire popped off the bead. Then again, he pulled the same thing w/ fully aired tires once. HaHa he has a stock 2wd ranger that gets driven like a trail rig.

2wheeler97

where is san ramon? i'm from lompoc, about 45 min south of pismo.

Robinhood150

San Ramon is up in the bay area. I went to Cal Poly SLO though. My former roommate's grandma lives in lompoc.

Yeah, the lower pressure you go the more skill it takes to keep the bead. But if you do roll the bead off then you can try that cool exploding tire trick to re-seat the bead! Just kidding, if you do blow a bead then either use a powertank to reseat it or use a ratchet strap around the tire and an air compressor.

10 psi should be good enough.

Steve

Victor

I say start at 24 and work down in 2 PSI increments. I think 15 PSI ought to be right but I've never been in a 4th gen so I have no clue how it will perform.

2wheeler97

my friends roommate tried that stupid explosive bead seating trick, worked too, stupid though, considering they lived a few blocks from two autoshops and a gas station.

Bumpin' Yota

What is this "explosive bead seating trick" you all speak of? Are you lighting your copilot's farts after a big bowl of chili or something? lol

Steve

Robinhood150

Think "potato gun" and "reseating the bead"...

Hermes

I have the same stock Dunlops but in 265-70-16. I go down to 15 psi and have a ball playing in the deeper stuff and exploring around the dunes.

However, it's always good to have a buddy and a tow strap, just in case.

Don't forget to lock that center diff

obxfishn

I found that if you go to about 15-18psi it allows the tire to balloon out enough for terrific traction.

Victor

The bead seating trick is you use starting fluid. Spray it in the tire and then when you light it the sudden expansion of gases pops the tire on the bead. This is great if you are out in the middle of nowhere but really most shops charge what - $6 to mount a tire?

seafarinman

There is another trick for seating the bead. You take that valve core out of your tire, set the regulator to 150psi on the Power Tank and let it rip! seats the beads every time. That is if you have a Power Tank. I haven't tried driving on the sand yet, but in the snow I was running 0 psi and never popped a bead. I am running Pro Comp Mud Terrain 31x10.5x15's on Unique Street Lock type rims.