corrogation and tires

corrugations, well spell check likes it, lol. Yes, the best thing to do, depends on the vehicle weight etc and the corrugations and other conditions etc, but down to 25 or so and drop your speed accordingly. Lots will support the lower pressure, others will say, never done it, never had a flat, they are the lucky ones.......

Hi John
We have driven may places from not so bad corrugations, to sections where you think your vehicle is going to fall to pieces because they as just bone bleep tering. I always let the tyre pressure right down and it makes the biggest of improvements. Also your tyre will act like a giant shock absorber, saving a lot of stress on your vehicle. If there are people that say it is an old wives tale, all I say is do a section with tyre pressures dropped, then inflate then to the usual pressure and feel the difference from inside the cabin of your vehicle. They do not drive very far before stopping and dropping tyre pressures.

Cheers

Stephen

I recently drove across the Plenty with tyres up, did the same on the Tanami. I have to be honest and say that the ride was as rough as guts. Finally got to the Gibb River Rd and decided that l would drop the pressures down to 25psi. Not only was the ride more comfortable, I didn't get a puncture while driving the Gibb River Rd, (which included a side trip to the Mitchell Falls and Kalumburu). I use to think that dropping the pressure would expose the weaker side walls to extra danger. I now wouldn't hesitate to drop the pressures on corrugated roads.

Cheers,

Geoff

Same here always drop pressures to approx 25 /28 psi if the corrugations are bad including the camper trailer.

I'd hate to see a tyre blow out due to overheating though...

3 bad areas in WA: Turn off to Cotton Creek to Georgia Bore on the Talawana, North of Well 33 on the CSR and areas of the Gunbarrel near Everard Junction.
All these places I've travel 40 all round. Yes - It massages your back, however the cruiser handles Ok, and will be even better now with a suspension upgrade!!

Cheers
Alan

Thanks for all your replies people. I'll add this one in...recently on a trip up to Cape Melville, the country was a mix of this and that. We drove into silica, sand, and then out into stakes and sharp rocks, roots, then more sand and silica. On the way back we took a different track (200 kms in 9 hours) which was mainly bull dust and sand, and dried up river crossings.
Now with the changing country every kilometer, it would be very time consuming to stop, let tires down, inflate tires etc. i mean surely you wouldn't leave the tires down at 20 psi after crossing sand and then going through stake and rock country?
On this trip, i left all six tires up at 40 psi, and just used the gears to get me through the soft spots.
but yeah the corrugation was a killer!
John

John,

Dropping pressures is common practice. How far depends on loading and obviously you need to slow down a bit. You should also check tyre temperatures periodically - the pressure is too low if they are hot to the touch.

The benefits - more comfortable for occupants and the vehicle of course, But also:

Less prone to spiking. (Try bursting a tight balloon with a pin - easy. Now try it with a partially inflated balloon - much harder.)

With the tyre actually working, much easier on shocks - check them for temperature at different tyre pressures.

The big plus - a bigger footprint on the ground - better traction , averages out road roughness. On loose surfaces there's less digging in at lower pressures.

It is important to drop your speed, along with the pressure.

We run on fat tubeless tyres when going into rough country. Our bitumen pressure (when hot) is about 40 psi, depending on loading. We'll drop about 20% (to 32 psi) if there's lots of gravel, down another 5 psi if it's badly corrugated. On sand we'll go down 50% or more. The absolute lower limit for us is about 12 psi - and that's for when we are very deep in shi...., no, I mean sand. At even lower pressures there is the risk of the front wheels walking out of the tyres unless you use minimal steering. These pressures suit us, but will be different for different vehicles. different loading, different driving patterns so I'm not recommending them, they are just for illustration.

On the Canning recently we experimented and finished up with trailer tyres at 8 psi and the Troopy at 18 psi all round. There was a huge improvement in going from 20 down to 18. At 20 psi we were stopped by one dune, at 18 we sailed over it. We had no tyre problems, lots of traction, relative comfort for selves and Troopy.

Met one traveller on the Canning who was having a hell trip. Dropping his pressures a few percent for sand, then went back to full pressure for stony areas. He spent more time adjusting pressures (and digging!) than driving.

Tyre pressures are probably the single most important variable in rough country. Jol Fleming is a highly respected member of the 4WD community and his website is a good source for anyone travelling in the centre. Jol's article on tyre pressures is here and well worth reading.


HTH

John

Another vote for dropping tyre pressures on corrugations.

Hi John,

I adjust mine, but I dont go by pressure, I go by the look of the tyre, Then I check with a pressure gauge purely to ensure they are equal.

I like mine to "bag" a little and this will depend on load etc to get the correct psi.

Imho they ride softer and I dont seem to get as many punctures this way.

If you call the Pink roadhouse at Oodnatdatta, He might be able to give you some more info if you ask nicely.

Cheers Wilko

John

I drop my pressure from 36 to about 28-30 psi. You can really feel the difference.

i dont do this in my own car but in the work landcruiser i travel in high four on corrugation, there is alot of difference.

cheers

I run tubeless and also drop my pressures for corrugations. In theory I'd rather damage a tyre than damage the vehicle. The only time I've had an issue was when I was running 18psi on the Anne Beadell and Gunbarrel Hwys in 45 degree heat in November. Got some mild delamination which I discovered back home in Adelaide.

If I were to still run tube tyres and split rims, I'd keep higher pressures to prevent tube fatigue. But I stopped using splits 10 years ago.

Hi John
I have always lowered tyre pressure when running off the sealed roads. The main reason for that is to improve the ride and lesson the chance of getting a flat.
I have travelled 26,000 ks in my Troopy so far and get off the seal every chance I can, frankly I hate travelling on highways.
On gravel and gibbers I drop the pressure down to 30lb cold, on sand I have never needed to drop below 20lb, but would not have a problem dropping further if required.
After an hour or so I check the temperature of the skinnys, if they feel hotter than the air temp, I am travelling to fast for the pressure so would inflate a little or slow down a bit.
On the last trip I drove from Birdsville to Inananinicka vie Allabury 600 or so Ks of gibbers and corrugations, I was pleased to get there I must admit, with no problems, apart that the stock standard shocks were that hot, to stand up inside was a bit like standing in a dinghy, however an hour or so later when the shocks had cooled the Troopy was as stable as ever.
A few days later in Tibooburra a guy and his wife pulled in beside me to camp,
said Gidday as one does and he started into a tirade about the condition of the road from Wannering, he had got a flat from a gibber fragment, poked right through the tread it had, what a terrible road, surprised me a bit because I thought it was dune red sand type country.
I asked what tyre pressure are you running, I don't believe in lowering tyre pressure just a waste of time he snapped. I just shook my head and walked away. If he carried on in the Nissan with a slide on camper he would be sure to pick up a puncture or two in the tubeless tyres if he kept them at the same pressure.
I went on to Hunger ford the next day, I thought the road was great, some sand and bulldust patches, nothing like some of the gibber roads I had been on a few days previoisly.