Tire Pressures

Whats it say on the side of the tyre so far as maximum pressures??

Probably be something much higher than 38 psi particularly if they are light truck tyres??

4psi the sticker recommendation is generally a good place to start. Measure the contact patch (ruler behind and in front horizontally, measure space between) and adjust pressures so they are same front to rear. These tyres should be able to take at least 60 at maximum load so you have nothing to worry about.

OT

Hi Steve,

If you intend on rotating them regularly then you are probably not far off that with the k's on them so talk to the tire shop at this time about how they are wearing. I have no doubt the a/t's will be fine at 38psi but as to how they will wear at that pressure depends heaps on so many variables like load, road surface, aggressive driving style or not ect ect so it boils down to going with averages and keeping a close eye on them and changing things at the first sign of trouble. I run 40psi in the Patrols and add a bit more when towing the van (generally go to about 44psi), no hard and fast reason why but it has worked well for me over many sets of tyres so I will stick with this until I see problems and adjust accordingly.

Cheers, Trevor.

Try taking the TIRES off and fitting some TYRES

The tyre guys in the city always recommend and put high pressure in. If you drive a light car like an xtrail with the pressure in the high 30's on corrugated/gravel roads then odds are you will get a bulge in the side wall especially if the profile is on the lowish side. It happened to me last trip to the centre in my Freelander 2 which is a comparable size/weight. The garage out there at Oodnadatta told me so (Mt Dare did too). They both recommended mid 20's on gravel/corrugations, lower for lighter cars. The big forbies like Cruisers and Patrols can handle higher pressures and need them to carry the weight. Also, the tyre construction for the big cars is way heavier in the side wall.
Personally, I don't like the ride on tyres inflated up high. My old 98 Pathfinder had Uniroyal Laredos on and I got 100,000+ kms out of them running at 28psi everywhere including town so any argument about low pressure and reduced mileage is lost on me. Perhaps you pay for comfort a little in fuel economy but it doesn't seem to change too much in my experience. Also, I think high pressure tends to shake and rattle bits and pieces off the car. Around town I now stick to manufacturer spec or a fraction lower, but thats my preference because I prefer to back a design engineer over a tyre fitter and it fits with my comfort factor. At the end of the day I reckon its a Ford/Holden argument with advantages and disadvantages to both schools of thought.

Mike

Coopers put out a 4WD Drivers Guide about Tyres & might be worth you getting a copy from your local tyre dealer.

In it they refer to the "4PSI" Rule & the rule applies to bitumen road use only.
It states: For passenger tyres inflate your cold tyres to the recomended pressure on your vehicles tyre placard. Drive for at least 20-30 minutes to ensure they have reached operating temperature & then check the pressures again. Idealy, they should be about 4PSI above cold pressure. If pressure is more than 4PSI above cold pressure, add more air.

Conversely, if they are less than 4PSI above cold pressure then the cold pressure is to high.

Steveinoz

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What pressures we used, in the Canning

ThreadID: 71971
Posted: 2 Sep 09 12:59

Cheers
Bucky