I've got a set of 18's on my VP Commodore with 235/40 tyres and was wondering what would be the ideal amount of pressure to use for the tyres. A mate of mine said I should use 36-38psi and the place I got the mags from said I should use 38-40psi, so I've been using 38psi all along. I do about 200-250km a week of highway driving and around up to 100km of city driving. Is 38psi enough? or is it too much/not enough?

standard car tires recommend lower pressure to make a more smooth ride.
i put 38psi into my mag's which as 17" 235's. i prob wouldnt go much lower then that. and max i would put would be like 42.

higher the pressure means less rolling resistance, means you save more on fuel, and likely to have to have less tyre wear. At the expense of a harsher ride.

I run my Stock 13" on my pulsar at 2-4 PSI above Nissans recommended pressures

for 18's daily driving i'd suggest 34psi COLD!

ie, fill the tyres up after little to no driving. (air expands as heated...it'll end up being 36-38psi anyway)

you're running 18's anyway, so ride quality is a lot less than what it's designed to be. a little bit more is not that much difference in my opinion.


for 18's on track days 38psi cold.

and for 18's on drag days 22-25psi cold.

too high a pressure can also reduce your contact patch, and hugely extend your braking distance

my manual says to put 24psi for my 13" thats seems a bit low to me

I had new front tyres just put on and I checked the pressure and they were 40psi, so I took it on the highway to see it how handled and yeah, the steering wheel vibrated more then usual lol. I think I'll try 40psi for a while to see how slower the outer edge on the tyres wear down.

i'd really only run 40psi if you were on a track mate.

i wouldn't recommend it for daily driving.

Ok I'll go back to 38psi, alot more people recommend it. The vibrations from 40psi kinda gets annoying after a while lol.