Tyre Pressure question?

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Re: Tyre Pressure question?

This still leaves me all confused. Plenty of people seem to say "This is what I use" but I cannot see anyone quoting any thing other than personal opinions.

Tyre pressures are subjective and it all depends on what you find comfortable with. I.e. you need to balance handling, comfort and fuel economy.

Surly the vehicle and tyre manufacturers should know best.

The tyre placard recommendations are there so that the dealers can pump them up to that [low] pressure so that when you take a new car for a test drive, you marvel at how well the car soaks up bumps. If the dealer is selling WRXs, they will probably pump up the tyres a bit more as the typical WRX customer is going to punt it along through the corners.

I've been running my MT/Rs at 40psi and it seems to be a bit too harsh and the steering is a bit nervous. So I'm thinking of dropping them down to 36psi.

There is no hard and fast rule as it all depends on how you want the car to feel. Going higher than 29psi will mean that the sidewalls are stiffer and the corner handling would improve. Having more pressure means that the tyre is rounder and therefore less rolling resistance, which equates to better economy. Also, the sidewalls do not bag out of the sides as much and so is less prone to heating up. You will then find that you can feel more of the bumps on the road.

When I bought the Prado, the previous owner must have followed the tyre placard to the dot. After picking up the car, I found that I could not feel the cateye lane markings when I drove over them. The handling was a bit soggy but the ride was plush.

[Snaga Wishing I was lost Find all posts View Profile Close Snaga]

Re: Tyre Pressure question?

Can anyone point me to AUTHORATATIVE info on why I should use different to the manufacturers recommendations?

As far as I'm aware the only people to put anything in writing are the Cooper Tyres mob... their '4WD Driver's Guide' is probably the only thing published by the manufacturers.
http://www.coopertires.com.au/index....free-info-pack

[Rusty62 Advanced Member Find all posts View Profile Close Rusty62]

Re: Tyre Pressure question?

I don't think anyone can say, legally what tyre pressure you should use. If you were to have an accident, at fault, the insurance will check you tyre tread depth and possible pressure. If the tyres were underinflated this could cause an accident, but over inflated (to the placard) would not.
You will be the best person to decide what pressure to use. If you want to stay at the placard pressure that is up to you. As said by many in this discussion many have been running approx 40psi and have proven to have better road handling and longer tyre life. With the rolling resistance reduced, fuel use will be better as well.
The best thing for you to do would be to do a check on fuel economy, at least 150 litres with placard pressure, then the same for higher pressure. Measure the result and make your decision based on your findings.
My 120 has had a slight improvement with 40 psi, but for me the handling and tyre life are more important.

[hulbyw Senior Member Find all posts View Profile Close hulbyw]

Re: Tyre Pressure question?

When I had my Yokos fitted, the tyre dealer put a sticker in the door jam with 34psi marked on it. This is what I use for around town and have no problems.

[Rusty62 Advanced Member Find all posts View Profile Close Rusty62]

Re: Tyre Pressure question?

Just got back from 4 weeks in Cape York.
Tyre pressures influenced the car more so than my older 80 series. We found that anything over 30psi on the corrugations would have the rear end skip sideways. (King springs and Bilstein). Most of the OTL at 25psi. Off road from Laura to Maytown we ran 25psi car and 20psi trailer. No punctures on all 3 cars or trailer.
Highway pressures 35 to 45 psi car and 35psi trailer. Running BFG A/T 265-70-17 on all cars and trailer.

[Boomslang Senior Member Find all posts View Profile Close Boomslang]

Re: Tyre Pressure question?

Well it has been almost a year since I commented on this thread and since then I have done a lot of off roading and learn't a lot from the Land Cruiser Club and their hard core members.
My new presures are:
Bitumen: 40PSI
Good dirt roads with speeds up to 80km/h: 30PSI
Slow going off road terrain like the powerlines/rocky terain etc: 20PSI
Sand / Beach: 15 PSI

When struggling, off road (hill climbs and obstacles) or in the sand, I'll drop down even futher. I've been down to 17 on the rocks and 10 on the sand. With the on board compressor, it is easy to make ajustments on the run. Correct pressures are more important than what most people think. Invest in easy deflators and easy to operate compressors and you'll enjoy your off road experiences even more.

[Boomslang Senior Member Find all posts View Profile Close Boomslang]

Re: Tyre Pressure question?

Well it has been almost a year since I commented on this thread and since then I have done a lot of off roading and learn't a lot from the Land Cruiser Club and their hard core members.
My new presures are:
Bitumen: 40PSI
Good dirt roads with speeds up to 80km/h: 30PSI
Slow going off road terrain like the powerlines/rocky terain etc: 20PSI
Sand / Beach: 15 PSI

When struggling off road (hill climbs and obstacles) or in the sand, I'll drop down even futher. I've been down to 17 on the rocks and 10 on the sand. With the on board compressor, it is easy to make ajustments on the run. Correct pressures are more important than what most people think. Invest in easy deflators and easy to operate compressors and you'll enjoy your off road experiences even more.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Re: Tyre Pressure question?

Boomslang wrote
Correct pressures are more important than what most people think.

Spot on there Boomslang

I would go as far as saying tyre pressures are the single most important factor in having a succesful day 4Wdriving our touring in the outback. All the others mods and techniques have their place, but without the correct tyre pressures you are behind the 8 ball before you start. I would add that as most 4Wdrives tend to run more wieght over the rear axle than the front you can often run 2-4 PSI less in the front.

This thread covers suggested pressures viewtopic.php?f=22&t=5262

Everyone needs to work out what is best for them though, on our reccent cape york trip my mate in a grossly overloaded 100 series decided to use the same pressures as me, it didn't work and he destroyed an almost new BFG because he was carrying much more wieght than me.

Cheers Andrew