<span class="highlight">tyre</span> <span class="highlight">pressures</span>

I firmly believe lowering tyre pressures on outback tracks is the best thing to do.When traveling the Gibb River Road and the Bungle Bungle tracks i dropped my pressures to 25psi on my Patrol.It gave me a good ride and punture free.The same cant be said for several other travelers who we came across using road pressure.But some people cant be told and puntures and destroyed tyres is the result.Not to mention damaging the tracks.

It can end up a bit of a choice between a puncture through the tread, or through the sidewall.......speed kills (tyres)

Cheers Andrew

Have a talk to locals that have good evidence to back-up their theories. Talk to the garage owners at Copely or Birdsville. These people have to repair the damage wheels from people who have been traveling to fast when to heavy and at to high a tyre pressure every day.

Made the mistake of running highway pressures on the Strezlecki Track some years back. Got a blowout early evening, had to change it in the dark, put tent up in dark, etc. etc. Next day we drove from Montecollina Bore to Maree without a spare. I suspect it was from the build up of heat in the tyre. Lesson learned.

I am inclined to agree that speed and excessive loads cause more damage to tyres than pressures. I have found that lower pressures make a big difference on mountain tracks at low speeds but I am not so sure on flatter more open roads.

I will always remember a trip I did back in 1967 when I left the Army base at Darwin to drive to Sydney. I reached Mt Isa then looked at my map and noticed the road down to Boulia and across to Winton was marked in the same black line as the main highway. I assumed that meant they were both sealed so I decided to go via Boulia thinking I might see some Min Min lights. The road soon changed to dirt a few ks out of Isa and got progressively worse. At one stage I was following two wheel tracks and I came up out of a dry creek bed and went between a house and what looked like a barn. I got through to Winton ok and was pleased to see the bitumen again. Nobody thought about tyre pressures back then yet I got through with no flat tyres and no car damage, apart from a polished sump guard, simply because I drove very carefully according to the conditions. The tyres were Dunlop SP 41 street tyres and the car was a Morris Cooper S!

Years later I worked in the motor industry for rmany years in western NSW and the Snowy Mts. I can't ever remember the local people worrying about tyre pressures. The farmers drove their often overloaded utes all over their properties, mountain tracks and dirt roads in all weather with 7.50x16 tyres and split rims. If they were constantly having tyre problems they would have let us know in no uncertain terms.

Brian

I have tried both, 40PSI on gravel road resulted in rock through near new tread. 28PSI fully loaded towing Hawk no punctures or probs 3000k trip gibber and gravel.

Its not rocket science !

Drop your tyre pressures, drop your speed, and in all cases do not charge straight up the road.

Try dodging rocks, gibber, ect, and you will preserve your vehicle and your tyres.

Simple as that !

Cheers
Bucky

Hi

My experience has been over about 20,000kms with 'from new' Desert Duelers in a heavily loaded Triton - pressure 1: Highway and highway speeds; pressure 2: all unsealed roads- lower speed (80kph) and lower pressure; pressure 3: real low pressure in sand and extreme rock hopping - very low speeds.

Never had a puncture and still got the same tyres on 40,000 kms later.

Happy days
George

If ever there is a person qualified to give advice on this topic it is Jol Fleming, Director of the Finke Desert race for years (which runs up the Fink river Rd, with lots of exposure to the dreaded rail spikes). He is also the Director of 4WD Awareness. He is adamant. Reduce pressures (and speed ) off road. There was an excellent illustrated article on his website explaining why. His website seems to be down at the moment, but Google for Jol Fleming and you might be able to locate it.

Pop,

You raise the question for me as to who changes, or more the point, doesn't change their tyre pressures on the bitumen?

Does every one run the same pressure urban/low speed running empty, and higher speed running loaded?

I know I change pressures for bitumen with different speed and load combinations, so why not for tracks/dirt?

I think the real question is how much to lower pressures on tracks/dirt?
As mentioned above, different vehicles and tyre ratings require different pressures for the same track.

Thank you Ed C, that was the site I wanted. Old Plodder, I think the reasoning on the site is a good way to go about the calculations you refer to. Same logic.

I had my 2 bobs worth on the last post re this subject so will only
add that if it is necessary to lower pressure to prevent suspension damage you are....1. travelling too fast. or 2. your suspension is not up to the task you place before it. My experience says higher
pressure costs me less money..so high it is.....oldbaz.