Tyre Pressure

Glenn I run mtrs 32*11.5*15
On the black stuff 40 psi
On the ruff stuff depending on load front 20 rear 24

All the best
Eric

Ditto...When you run less you can tend to wear out the centre first...

I'd think it would depend a lot on weight.

I have 31in MT/Rs on a Rodeo but I wouldn't use the same hway pressure as a Cruiser. Try the 4psi method. I did and ended up settling on 34f/32r for bitumen.

on my jackaroo i was advised by dealer to run 40 psi all round, well it was good in a straight line but hopeless cornering and couldnt be stopped in the wet, just hopped and skittered everywhere, now using 34 all round and it is heaps better, no real difference to the noise. And when running they go to 38/39 hot, so its pretty spot on.

4 PSI RULE - basically if you run the correct pressures there will be a 4 psi difference between cold and hot pressure. Check out the Sime tyres website, they have a really good explanation on the subject.

Glenn,

Run MTR's(235.85R16's) on 79 series tojo, with skinny rims. Run at 34-36 psi, on bitumen, gravel and station roads. Would run them around 32-34 if had them on 7" rims.

We kick 'em up to 40 if it's loaded, or hot, and going for a quick trip on the black stuff. Only time I'll let them down is if it's wet, and I want to get home!!!

Am on 2nd set, and the original ones wore evenly, at those pressures. In fact, got about 50K out of most of the first lot. Good for this country. Like the TG wranglers as well, in 750R16.

Hooroo...

Glenn, I know this page does not answer your question directly but will dispel some myths supported elsewhere, It is a Canadian site discussing tyre pressures and the potential costs of under/over inflation. Just click the Link and scan to see the wear versus contact area. I think it should correct a couple of ideas.

Hi Glenn,

The link to the Canadian site looks fairly good. My company sends most of it's employees on a specialist driving course. The advice there is to always inflate tyres higher than the vehicle manufacturer recommends. This is because the manufacturers go for lower pressures to increase ride comfort. Lower pressures lead to increased side wall flexibility which reduces handling and increases heat.

Most vehicles run with under inflated tyres, just go and have a look at the old tyres behind any tyre outlet, I doubt that you will find many, if any, worn out down the middle through over inflation. Some people have mentioned that they run lower pressures on gravel, well each to their own, when in the Kimberley I was advised that the local police and prison service always run on high pressure tyres on gravel, most blowouts on gravel are due to side wall failure from flexing and heat build up. Of the blowouts I saw on that trip - about 10, I would say that 7 of them were side wall damage.

The opinion of the course instructors was to always run on high pressure - in your case at least 42-44psi, and even for small passenger vehicles 40psi was recommended. The ONLY exception was of course for driving in sand where very low pressures were recommended, though not so low that the tyre comes off the rim.
Sorry if this just adds to the confusion!

Greydemon

Yep,

I agree with Greydemon in that the "Drive Safe" Instructors recommend a higher pressure. I too, have done one of these courses.

However, in relation to this and also the Canadian site, I can't help feeling that the logic and comments relate specifically to your standard passenger vehicles with standard "black top" tyres.

I would support the comments made by Utemad and Bradley.
I am also a believer in the 4PSI rule. This will work for everybody and every car.

EVERY CAR IS DIFFERENT... TRIAL AND ERROR.

How much weight does your mate have in his car?
How many accessories are weighing down his car?
Does he tow?
What size tires?
Where does he live - eg Temps of the road/ambient etc?
What roads does he drive on?
What suspension does he have - firm or soft?

MTR's in a 33x12.5's as my daily tires on my Patrol... 40psi is like driving on solid rubber blocks! No give at all. IMHO.. IYDGFY :) I run 36 all round at moment on road and its good.

Down to 22-14 offroad if needed they bag out well.

Will Go MTR"s again when Royce buys these off me.