Thread: tyre pressure

Hi Pullsy

i run my 235 x 85 x 16 MT at 40 PSI with an average load on the road
and 18 to 20 psi off the road

kai

Yup, the LT bit is light truck, some tyres have C to denote light truck as well I think.

They can take higher pressures, but don't neccessarily need them :wink:

35 to 40 is heaps for a loaded vehicle unless you are carrying huge weights.

What type of car?

35-40 should be fine, depends what sort of ride you want on the road, 40 hard 35 smoother, if you were offroad then its sort of opposite lower pressure 25-20 gives better grip, but does expose the side wall to more damage.

Glen.

Pullsy

Correct tyre pressures can vary depending on the vehicle type, tyre sizes, weight your carrying, where your driving and probably heaps of other factors. There may be a sticker on the drivers side door frame or on the edge of the door itself which has recomended pressures for your vehicle. That would probably be a good starting point.

Something I got told years ago was the 4 PSI rule. Basically check your tyre pressures when they are cold. Go for a good drive (about 1/2 hour or so) to get the tyres up to full temperature. Check the pressures again using the same tyre guage. If the initial pressure was correct the tyre pressure should have now gone up 4 psi. If it has gone up more than 4 PSI your starting pressure was to low. If gone up less than 4 PSI starting pressure was to high.

I've used this rule and settled on 30 front and 38 rear in a discovery with 225/75's. The front is a bit higher than recomended by LR as I have a bullbar winch and dual battery system adding weight to the front. She seems to go okay with those pressures. Those pressures are for normal daily driving. If I'm loaded or towing the rears go up a bit.

Good luck

Iain

I run my SIII and Range Rover at 60psi front / rear. I find they cruise, corner and brake better. If the tyres ever seep down to 30 or 40 psi the car feels sloppy. You'll get better economy with higher pressures too.

I get over 100,000 km from a set of tyres and I don't buy expensive tyres.

Why not try them at 60psi for a trip, see how they handle and then decide.

I know it says they go to 80psi, but unless you're carrying a load,anything over 60psi will see the centres wear out faster than the edges.









sorry to digress so far from the median opinion :wink:

i would say 60 will wear the centres out......i did at 50 psi.


yes it does handle better but will also be harder and harsher and will tend to bounce a bit on small bumps(makes going around bends lots of fun [img]style_emoticons/<#EMO_DIR#>/laugh.gif[/img] ) but i guess every tyre is different and will perform differently with different cars and loads.
also running that hard in the wet will be worse due to the fact that the harder a tyre is the smaller the footprint.

i guess its all trial and error then finally personal prefference.

one thing i have noticed is that the recommended pressures do feel a bit too soft on any car i have driven so i always run a bit higher pressures than required.

Originally posted by Michael2
I run my SIII and Range Rover at 60psi front / rear. I find they cruise, corner and brake better. If the tyres ever seep down to 30 or 40 psi the car feels sloppy. You'll get better economy with higher pressures too.

I know it says they go to 80psi, ..

60 psi! Hell's Bells. It must ride like a 70 series Land Cruiser.

What are they like in the wet? Do they have any grip? Also, before going that high, check the maximum pressure on the tyre. I think some are only rated to 50psi

I run the pressures recommended by the manufacturer.

Ron

Originally posted by fossil
Pullsy

Correct tyre pressures can vary depending on the vehicle type, tyre sizes, weight your carrying, where your driving and probably heaps of other factors. There may be a sticker on the drivers side door frame or on the edge of the door itself which has recomended pressures for your vehicle. That would probably be a good starting point.

Something I got told years ago was the 4 PSI rule. Basically check your tyre pressures when they are cold. Go for a good drive (about 1/2 hour or so) to get the tyres up to full temperature. Check the pressures again using the same tyre guage. If the initial pressure was correct the tyre pressure should have now gone up 4 psi. If it has gone up more than 4 PSI your starting pressure was to low. If gone up less than 4 PSI starting pressure was to high.

I've used this rule and settled on 30 front and 38 rear in a discovery with 225/75's. The front is a bit higher than recomended by LR as I have a bullbar winch and dual battery system adding weight to the front. She seems to go okay with those pressures. Those pressures are for normal daily driving. If I'm loaded or towing the rears go up a bit.

Good luck

Iain

I like this theory, in fact the thing its talking about is Hot and Cold flex times - its also another reason why you rotate tyres regularly. The less hot flex times a tyre has the longer it will last.

Its a good sound theory and from my experience it works well in practice, the 4Psi thing is a way of limiting those flex times.