Tyre Pressure?

Synergist,
I think you'll find that the pressure marked on the sidewall will be the pressure at which the tyres' Maximum load is rated.. This will usually be marked on the sidewall as well...
38-42 psi seems about right for light-to-moderate load on a FJ55...

Regards, Ed. C.Confucius say.....
"He who lie underneath automobile with tool in hand............
Not necessarily mechanic!!"

gday synergist.
that pressure is wayyyyy to high.
with out a load run around 34psi.
then add according to your load.you reckon your cute
richard(eskimo)
but im a lot cuter

Cheers guys, being a newbie to this game, any help or feedback is much appreciated. So if anyone out there has advice or info on the old girl (fj55 76') that would be great!

Hmm Tyre pressures..
Quite simple really, you just need to take into account, the load on the tyre, the speed you are travelling at, the type of terrain, the type of tyre, The tyre size, colour and gender orientation then multiply it by the phase of the moon and divide the answer by two.

OK maybe not.

Starting point for tyre pressure is the tyre placard on the vehicle, this will give you the minimum recommended pressure for the standard vehicle, usually loaded and unloaded. This information is also available in the Tyre and Rim Association manual based on the tyre size.
On bitumen roads increasing the pressure will reduce the rolling resistance, however you should never go over the maximum printed on the sidewall. The stiffening effect of the higher pressure also improves steering responsiveness but the vehicle can become more nervous as well as riding harshly. The higher pressure also reduces heat buildup.
On gravel and dirt the higher pressures can lead to impact damage due to rocks and stones etc being forced into the tyre because the tyre can’t mould itself around the object.

The tyre and rim manual also shows the effect on load carrying of differing tyre pressures. The 31x11.5 R 15 LT varies from 665 kg @175 Kilopascals (app 25psi) to 1060 kg @ 350 kilopascals (app 50 psi). This applies for road speeds up to the design limit of the tyre.

When off road it is common to go lower than recommended to gain traction and improve the ride and this is possible because the ability of the tyre to handle a load goes up as the speed comes down. This requires a serious commitment to monitoring pressures and being aware of that dreaded tyre killer, heat buildup.

Where to start? Weigh the vehicle loaded, they are usually a lot heavier than you think. Get separate reading for front and rear axle then divide each by two to get the tyre load.
Check the tyre & rim manual (tyre services should have them) or the manufacturers website for minimum pressures for that load then add pressure till the vehicle feels good to you. If you get a large difference between hot & cold then you are probably running too soft for the conditions.

Off road depends on surface and speed, just remember that road pressures destroy sand tracks.

Enuff for know. I hope I got enough right to get you thinking

Regards

A

Hi Synergist !

Tyre pressure mostly depends on the load rather than other things.
There is one very simple and reliable way to maintain the correct pressure - the rule of thumb - cold pressure should be increased by 4psi after 1 hour of driving on bitumen.

Check out this link:
Tyre Pressures

Cheers,

Dmitri.