<span class="highlight">Tyre</span> <span class="highlight">pressures</span> landcruiser 80 series

Lowering tyre pressures down to around 25 on dirt and gravel will make your vehicle more comfortable on corros.

Last year I ran 2 100series and 1 troopy with 265/75/16 Oz made bridgestone a/t duellers, I run 40 front and 42 rear and with passengers they run smoothly.
Now some people say run them way less than that, but let me tell you: my trucks did approx 80,000 km between them last year on corrugated dirt roads with out 1 puncture.
Some would say this is lucky, but over the last 6 years I've used the same tyres and the same pressures, on an 80 series, a 75 series, a 78 series and 2 100 series, with similar kms on dirt roads with similar results.
Cheers Steve Top End Explorer Tours.

Jim,

Most people living in the outback and using good dirt roads, read usually corrugated and with a variety of surfaces, would run tyre pressures around mid to high 20's this seems to help with tyre ware and does make it more comfortable.

Personally when travelling on bitumen highways I run about 40psi, around town I run about 35 and when I get to the good dirt I run 26. That is what works for me and was recommended to me by the tyre dealer in Broken Hill. On my last trip I was feeling that the 26 was a little low, the road was very good and I was travelling pretty quick.

The short answer to your question is, yes you will be more comfortable and provided you aren't silly about how low you let the pressures get you will not do damage. If the pressure gets too low and the speed gets too high then damage will occur. due to overheating. I doubt that pressures in the mid to high 20's will significantly increase the risk of punctures.

Steve, I am not criticizing you but I wonder if reducing your pressures a little might just make your passengers a bit more comfortable without impacting on any other aspect of vehicle operation.

Duncs

Radial tyres are suposed to bag a little ! Anyone who uses 40 psi does not understand how their tyres are suposed to work. Yes, you can use that pressure but you are not getting the 'best' out of the tyres - like a comfortable ride and helping the suspension ! I use no higher then 25 psi and where conditions allow travel at about 75 kph and get a good ride.

Jim,

As with Steve I run at a higher pressure than most others on this forum, but I would bet that we do kilometers in a month than most would do in a year.

38 psi is the pressure that I would recommend to any drivers that are in the convery that I take away.
The only time that the pressure is dropped is when we get onto sand, and then we only let them down to a pressure to get through the sand. Going straight to 10 psi is only asking for a blow out. Even in the Simpson Desert and the Canning, 20psi front and 28psi in the back. If the sand is soft then I would go down 2psi at a time but would never run any lower than 15psi.

Driving over corragations is more about getting the speed right.
Going slow with low pressure will flex the side walls and increase the chance of a blow out. Going fast with low pressure will also flex the tyre and and build up heat.

It is very hard to pick the right speed and pressure that is why we go on what we have seen and done before.

This is what I have experenced with vehicles set up to do a outback trip. With the weight and tyres that they are running.

Wayne

Its all a juggling act. I'll assume you're talking about severe corrugations.

Just my observations:
#1 lowering pressures make corrugations more comfortable
#2 travelling fast can make it more comfortable but greatly increases the risk of breaking bits on your vehicle, and rolling it.
#3 lowering pressures reduces the likihood of vehicle damage (suspension, chassis, body - even fusible links and batteries!)
#4 lowering pressures reduces the likelihood of punctures

But on the other hand,
Too low a pressure, increases the chance of sidewall damage due to excessive flexing and heat - causing delamination
Too low a pressure is not good for tube type tyres (split rims)

My suggestions:
#1 On your average loaded 4wd, 23F and 26R suits me for tubeless tyres (30/35 for splits)
#2 Keep your speed down, and don't overload
#3 Check and tighten nuts regularly - wheels, suspension, body, roofrack, battery etc etc

In general, I prefer to risk tyre damage which is fixable than vehicle damage which may not be.

Cheers
phil

JimDi,
I have an 80 series cruiser with BFG A/T's. I run 34front and 36rear. Rides very well. When loaded I increase the rear to 40psi only if it's very loaded and towing. My belief is that with Light Truck construction tyres is that they have stronger sidewalls / construction so 32 psi in LT tyre would be like 34PSi in a passenger car tyre.
I tried the higher pressures unladen and it made for a very bumpy ride and if anything only wears out the centre of th tread quicker.

Rob

40 and 42 will give you best wear and best puncture resistance....lower will soften the ride, and increase floatation but increase puncture of sidewall possibility...rocky terrain too much air will allow penetration of rocks to centre of tread...but 40 seems in the middle....i always ran 32 and always had worn centres from excess heat buildup due to too much carcus flex at that pressure....40 is better m8...
Also, it all depends on weight carried and construction of tyre...

Put me in with the 40/42 mob. I've used BFG A/T's for the last 3 sets and worn them all out. No blowouts. Have had the odd sidewall stake, but plugged them and kept using them 'til worn out. I've never had a rock go through the tread and I work in some really rocky/ shaley/ gibbery places.

Conversley, when I used to run lower pressures (mid to high twenties) I used to blow the odd one or two. I never, ever wore out a complete set of tyres without losing at least one or two. Blowing a tyre is not fun. I know the cause is always due to heat build-up because you can't touch the bloody things for about half an hour after you stop.

As for comfort? Well I'd rather feel few corro's than find myself careering off into the bush after blowing a tyre.

This might be a WA thing. I've noticed on other forums that West Aussies from the goldfields, Pilbara and Kimberley generally run harder pressures. South Wester's are a bit of a mixed bag - generally - there are always exceptions.

Try a few things, but if running lower pressures, stop regularly and feel the tyres for heat build-up. You can often "smell" a tyre that is suffering from being too low pressure.