Tyre pressures

[dustbug]

Just wondering what tyre pressures i should use for 225/30R20s?

They have the max pressure on the tyres but theres normally max 2 passengers in the car at once with a sub in the boot. I was thinking around the 34-36psi mark.

Would this be ok?

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[JasonGilholme]

If the load rating matches the car then you should run what the tyre recommends.

[low astra]

not quite, ive always found that the lower side wall tyres like a bit higher preasure to get a bit of milage out of them, like my cousin is running 40+ pounds with his 22"s i ran 40 on my comodores 18"s back in the day and got 50,000k out of a set

[mr_sikma]

34ish is always around the mark!

[digifish]

Just wondering what tyre pressures i should use for 225/30R20s?

They have the max pressure on the tyres but theres normally max 2 passengers in the car at once with a sub in the boot. I was thinking around the 34-36psi mark.

Would this be ok?

34-36 is a good pressure on most passenger cars. Run at the higher side of their recommendation...better fuel economy and handling at the sake of comfort.

Regards Scott

[dustbug]

awsome, thanks for that, i'll probs keep it at the 36-38 mark since some people are running at 40+

[digifish]

awsome, thanks for that, i'll probs keep it at the 36-38 mark since some people are running at 40+

Another thing to note is that most people check their pressures at the servo with at least a few minutes driving. All the specs say to do it cold. So driving increases the pressure a few psi. If they feel warm to the touch and you fill to 38 you are probably really filling to 36? Can't find a better graph...

http://www.pirellityre.com/web/techn...l/default.page

digifish

[Wraith]

not quite, ive always found that the lower side wall tyres like a bit higher preasure to get a bit of milage out of them, like my cousin is running 40+ pounds with his 22"s i ran 40 on my comodores 18"s back in the day and got 50,000k out of a set

This is correct.......however you need to observe for yourself on your individual car, how a certain pressure reacts in terms of uneven tyre wear and or longevity.

Very low profile tyres are best if inflated higher rather than lower.

If you ask tyre manufactures and fitters they'll tell you that 38-42psi is usually the case for a tyre with a 30 series profile.

I also have 225/30 R20's and run 40 psi - as I've found this to be optimum, the ride quality has not suffered as a result

[Mr T]

I have 215/35 R17 and run 40, the recomended 35 seams to cause excess wear on the edges.

[entice]

I agree with Mr T.

I'd get your decent Alignment shop to set the pressures for you. Preferrably if that alignment shop is involved in motorsport preparations.

Bugger teh ride comfort, even tyre wear and secondly performance is what I'm after. He set mine to 34-36ish (18's). havent touched them since, but am due for alignment check