Outer Limits 4x4 Board

How low can i drop the pressure in my tyres before I risk running one off the rim? I know it obviously depends on what terrain Im driving, but does it depend on what tyres im using? Im just after some guiding figures that have worked for people.

Cheers all!

Wellsey

Totally depends on the tyres, rim, and how you drive. I usually run my Swampers at about 8psi, 32x11.5 on 15x8 rim. BUT i have pushed them off the rim once or twice. What tyres and rims etc are you using atm, that would help a bit.

Layto....

0psi, well I managed to drive for a fair distance on my 31 Yokohamas with the valve cores pulled out.

It al depends, just try different pressures, some people can get away with single digit pressures others can't, there is no definite answer

Running 31x10 bfgoodrich highways on 15x8 sunnies at the moment. What would be appropriate for the beach?

you can run them real low so long as you don't try and corner at speed. I would recommend 10psi as low point without bead locks. I have found that at this pressure though its possible to get mud weged in the bead so your tires will go flat all the time.

I run 10psi in mine, 32x11.5 BFG's on 15x8 steelies. Most of my driving is pretty slow though and i havent had a problem yet.

Really, it is impossible to say.

The best pressure to run your tyres at offroad is about 1psi above the pressure they fall off the rims at- i.e - the lower the better.

What that figure is is dependant on lots of factors, but the biggest single factor is the driver.

I run 6psi with swampers and tubes, Christover has (inavertantly) run 2psi with tubes all day wit no problems, I would say between 6 and 10 is fine, but it is very dependent on rims, tyre, speed, terrain, and driver sympathy.

Buy a reasonable compressor, take a ratchet strap with you and a spare tyre and keep experimenting. there is really no big deal to loosing a bead.

With beadlocks, we have seen suzuki's go as low as 2 psi and the tyres are still effective. In this case we are talking a 36" swamper (although about 4 psi in the rear and 5-6 in the front seems pretty effective), but the point is there that in most cases, the most effective pressure in the tyre is way below what you would think.


Steve.

I popped a tyre off (on road) at 20Psi. But I run 205's on 7" rims (I dont recommend it, it sucks). I'm not game to go below 15 on mine because I run the narrow tyre with the wider rim. I replaced the tyres I popped off anyway, and run 205/75's, it still sucks obviously.

If you really want to go low pressure and are worried about the tyre removing itself, consider bead locks. They sell them for a reason. If you carry an air compressor with you, you could probably re-fit the tyre on site anyway.

if you letting air out your tires it would be assumed that you have a compressor and so a tyre off the bead isnt a massive problem.

A set of stauns are on the to do list, but they wont be happening for some time yet. Cheers all for your advice, keep it coming....

Stauns are OK, but setting them up is a bit of a PITA.

I have two sets, one set will be set up for "normal" off road use - maybe 7psi. the other set will be set "low" for harder terrain, maybe 3 rear 5 front.

This will be when I get the beadlocks on- they have some very flogged old Q78's on them that have been nicely broken in by me 2500kg Gwagen.

Really, if you have a compressor, just let down a tyre until it visibly bags down. this will be about the right pressure. Then put the gauge on it - you will be surprised how low it will be.

Steve.

i run 36in iroks at 4psi and am yet to roll one off on 8in rims, but have rolled them off at 3psi. So i think the theory of 1psi higher than the roll off pressure might ring true

Its all trial and error Ive always dropped to 10psi "just because" but recently Ive started going lower. I have lwb with toys and 33s on 8"rims.
I competed in J7 with 6psi and on the beach on sunday I went to 5psi and both times I didnt go easy. At 5psi they bag live bigger 4wds do at 10 - 15psi.
I remember reading once " you havnt aired down till you,ve popped a bead"
Nik

I used to run 29x10 Bridgestone Desert Duelers when I bought my sierra and ran them consistantly at 10psi offroad, played around with pressures and got down to between 7 & 8psi and they worked much better.
Then on the Silverstone 31x10.5's I could run down to about 6psi and managed to wedge mud in the beads on one side one day and accidentally discovered they hung on even at 4psi on an 8" rim...
These days, 33x12.5 Silverstone sports on 16x8 rims, I can go down to about 4psi with tubes, without popping the bead or spinning the rim in the tyre... yet

Just play with about 6 and see how you go mate- if you feel you can go lower again, go for it. As they guys have said, just take a ratchet strap to re-seat the bead if the 'experiment' pops it off.
Or a can of hairspray 'n a match... hehe!

yeah i can let my 35'' creepie crawlers down to 2-3 and havent had a prob. this is on 7'' rims, ill run em with nothin and see how they go........
as said above it definately depends on the type of tyre though!!

Muz

i run my 36 swampers at 5 on my zook and they dont even bag when sitting still. i want to let more out but not game tilll i get compresor or bead locks. as said before its just trial and error i think.
thanx
mick

mate with 32x9 simex on a zook on the beach used to take the valves out and put the valve caps back on and run it round like that. went good.

i run about 5-10 on beach with 31" muddies on 7s. 15 on mud/rock if i let them down.

Nic

just a side note , Try your hardest to fit the tires with no Soap or lubricant , its harder but it won,t come back to haunt you when in the wet or MUD