Outer Limits 4x4 Board

Hey people,
I'm new to the 4wd world and so far loving it. Not to keen on the fuel consumptions still. but getting use to it.

I have the pressure up (42) on my dessert duellers on the road to get a bit extra on the fuel eco on my 88 swb mav.

An issue that i'm having off road is that I keep slipping into wheel rutts and then get stuck in them.

if i was to lower the pressue when off road to say 20, would this give me more traction in clay and mud and allow me to pull myself out instead of just slidding into the holes.

Another question is how the front diff works.
Once the hubs are locked in, does the power divert to which ever wheel is easiest to turn. I know its now a LSD or a locker. So im taking a semi educated guess.

Thanks people.

Yes, lowering your tyre pressures will make a big difference offroad and also with your rut issue. 20psi should be good depending on what size tyre you're running. I usually drop mine on the GU to 16psi with no probs though. Plenty of grip then. As for the diff, yes if it has no locker or LSD then the power will be sent to the wheel with the least resistance. If one wheel loses sufficient contact with the ground the power will divert to that wheel and hence you will lose traction and possibly come to a halt. This is where a locker comes into its own by maintaining equal power to both wheels no matter what the contact pressure.

thanks for that.
I had an idea that was the issue with the tyres. That the higher pressure wasnt allowing the tyres to grip and "wrap" over the walls of the rutts. meaning that they would just slide up against it.

Dont get me wrong i know the lose nut behind the wheel is an issue as well.

It happend the other day when out and about and i'm now sporting a large dint in the rear gaurd right under the fuel filler. So not happy. 20 year old car, not dints and no major scratchs and even teh orginal stickers until i get it. Anyone know a good panel beater that wants some after hours cash work in newcastle?

Thanks for the help.

There's heaps of experienced OuterLimits members in Newy, nellyb. Maybe post in the General Chit-Chat section and see if you can tag along on a trip sometime? Best way to learn

Lower pressure will help protect against punchers aswell. I just went to Crystal Vale 4wd park and I ran 12psi in my 32's and it griped very well. Next trip to ormeau I might try 6psi just to see the differance and see if these staun beadlocks do there thing.

Just a note I believe if you run under 16psi without beadlocks you run the risk of popping a bead so dont go below 16psi. Im sure someone will correct me if Im wrong.

16 is a useful guide for a heavy car with regular tyres/rims, but there's lots of variables.

When I was running radials and alloys on my Gwagen the tyres would start slipping on the rims at 18 psi, but I never lost a bead.

Suzuki's though can normally run well under 10 without problems.

Steve.

What kind of pressure would you suggest for a 2,000kg Pajero with bias 34/11.5/R15 on an 8 inch rim. I have been using about 20 PSI, but think it might be better if I go a little lower.

What tyre?

Steve.

I can understand how lower pressure works with over rough hard terrain and sand. Does it work the same in muddy conditions too? I guess i'll find out this weekend up at the barrington tops. Heading up there with a mate to do some bike riding and 4wding. I'll give it a go and hope i dont bust a bead.

Thanks for the help tho people

to give you an idea - my zuk on 31's runs at 20psi on road... i havent had the NEED to let them down properly yet, but i did anyway and at 10psi theyre more spongy for sure, and definitely grip better.

Simex JT2's

Dexter wrote:Simex JT2's

... offroad on my GQ I ran my JT's down 10-12psi no problems. I want another set :(

Fark - On JT2's, from what I've seen you can't let enough air out of a JT2. They seem to work really well when aired down about 0.0002 seconds before they fall off the beads.

IMHO if you want JT2's to work, you really need beadlocks- I've seen too many fall off the rims to make me feel comfortable running them soft.

That said I'd be shooting for 8-12PSI in them on a pajero in hard terrain, otherwise 12-16 for medium standard driving.

Steve.

Well I think I will go for 16 odd PSI as I would prefer to avoid loosing it off the rim. Once I ware them out I will be heading to some LTBs or TSLs.

Bead reseating isn't that much of a problem, but they do always seem to fall off at the worst possible time - in a bog hole, 1/2 way up a steep hill or something.

I be searching for some second airs or beadlocked rims. Once you don't have to worry about loosing a bead, you can really get the tyres to work and get the most out of them - That goes for any tyre really. I've run beadlocked swampers since 2000 on my Gwagen and for the last 18 months my sierra hasn't run beadlocks - only tubes. I run 6 psi in the sierra with tubes and whilst I haven't lost a bead, I am chewing up tubes and the tyres are slipping, so the next thing I'm doing is going to beadlocks and ditching the tubes.

Generally, the point of diminishing returns with reducing tyre pressure is well below what you can run without beadlocks. On my Gwagen, it was at under 8psi. I was still gaining traction as I went below 8psi, but the loss of clearance and stability made it pointless except for exceptional circumstances. With suzuki's that point seems to be between 2 and 5 psi.

Steve.

HOLY FLYING CHESSEGRATER BATMAN!!!!

5-2psi.

My God.
you can almost blow that up using a straw jammed into the valve.

you will also obviously find more aggressive tyres will help you no end in ruts and mud. and the "side biters" etc are great like that.

where abouts at the barringtons are you off to?
you might not find as much mud as you expect.

Heading up to Ladies Well for some mountain bike riding.

Not really out looking for mud to be honest. I've been out wheeling 3 times now and everytime i've tired to position the car on either side of the deep wheel rutts, and i've ended up sliding into them and getting stuck.

It's normally the back that slips in first, which i know is my fault from not turning out wide enough. but yeh i can feel the car slid into them. The last two have been clay but not very deep. and i've had to dig away at teh wall of the rutt to then be able to get out. Just a pain. I'm talking maybe 20cm deep. Nothing really.

I think its drivers error mainly, so next time i'll lower the pressure and see how it goes. the joys of being a NOOB. lol.

stuck in a 20cm rut??? my mazda 323 sedan has driven 20cm rutted muddy tracks on bald road tyres... lol

Try and hook up with a 4x4 club - youll learn a lot about driving style =)

i hear you.
Ive got one myself and they are unstoppable little cars.

I must say that in my defence that it was clay mud, and loads of it. It wasnt like i feel into a pot hole and couldnt get out of it.

Yeh my mate and myself are going to join up with a club soon and head off on one of the out of town 4wd sessions just to learn a bit more.

sometimes if the ruts are small i drive into them (shallowest ones), most of the time if its ultra greasy you'll slip about regardless especially without a dedicated mud tyre and probably better to drive along a small rut for guidance than get crossed up across large ones - you can also try to put two wheels (right or left) in a rut - not too deep though so that the other side is on good ground, obviously all ruts are different though.

fwiw i hardly ever let the tyres down - i know it can help but i seem to be able to get most places without traction loss - thats with mt/r's or bfg muds, certainly if i was in sand, started to lose traction or off the road for a long period (not just a 1 hour drive) tyre pressures are the first thing i'd adjust.

While you're all talking about tyre pressues - can I ask a question.

I run Cooper ST 265/75/16 tyres on a '99 GU patrol. I have been told by the Cooper rep to run 29 psi to the front and 32 to the rear when on bitumen. Dirt roads to go down to 24 psi and the sand maybe 16/18 psi depending on the conditions. This is because the side wall needs to flex due to the hard compound of the tyres. I'm fine with most of that, but here's my question....

What psi do I run when fully loaded up (3t) plus towing a camper trailer (1t) along the Birdsville Track? I am heading up there next year and am not sure of what psi to run along the way.

It was explained to me to measure from centre of rim to the ground and then load 4wd as normal. The heavier weight on the axle will then push down the tyre and the idea is to put more air in to bring the sidewall back up to the original measurement. Does that sound right? In reality I could be running 40 psi of the rear.

Cheers,

Paul

bulla_bryant wrote:While you're all talking about tyre pressues - can I ask a question.

I run Cooper ST 265/75/16 tyres on a '99 GU patrol. I have been told by the Cooper rep to run 29 psi to the front and 32 to the rear when on bitumen. Dirt roads to go down to 24 psi and the sand maybe 16/18 psi depending on the conditions. This is because the side wall needs to flex due to the hard compound of the tyres. I'm fine with most of that, but here's my question....

What psi do I run when fully loaded up (3t) plus towing a camper trailer (1t) along the Birdsville Track? I am heading up there next year and am not sure of what psi to run along the way.

It was explained to me to measure from centre of rim to the ground and then load 4wd as normal. The heavier weight on the axle will then push down the tyre and the idea is to put more air in to bring the sidewall back up to the original measurement. Does that sound right? In reality I could be running 40 psi of the rear.

Cheers,

Paul

Wrong.. running 40 psi on the birdsville track fully loaded is a sure fire way to end up camped on the side of the road with 4 dead tyres!

Read here for a good idea on different presures..

http://www.outerlimits4x4.com/ftopic110 ... light=4psi