Ok, got the new tyres and now want to make them last as long as possible. With the 215/55/17 tyres on the 17x7 rims, what is the optimal tyre pressure people have found for even wear. So they perform best and last longest?

Sh00t got my Dunlop Sports and I ran them at 36PSI. They were in good condition at 35K.

When I replaced my tyres (sx series 3), the tyre shop told me 36 was the pressure

I run them on 40 PSI

Thats what is optimuim for HWY

for economy you should run 2 PSi over the optimuim

42 would seem very high for a 17 for everyday? Though, with the 215/55 size, they are different to the 17's you get on an XR6, which are lower profile, which is what I'm used to. These are a different ball game.

At the moment I have them all set at 37.

true thats why I run on 40 PSI

37 is good I would be doing 38 if 36 is what the tyre guy says

Every tyre guy is different, it's hard to know who to trust.

I run 39/40 in my 245/35/19's, so it's confusing what to use on 17's that aren't really a low profile tyre.

the various tyre guys ive spoken to suggest 38psi on a 55 or 60

mines so bad.!! running on a thin layer of rubbers. Will get new ones this month.

It says 32psi on the placard so that's what I've always inflated to. WTF? Should I be putting more in?

It says 32psi on the placard so that's what I've always inflated to. WTF? Should I be putting more in?

The recommended pressure on the tyre placard should be regarded as a minimum, and it's designed for a nice comfy ride, so when the average punter takes the new car for a test drive it feels 'nice'. Hardly anyone taking a new car for a test drive is going to corner at 9/10s or panic brake a few times to properly test road holding and braking and tyre performance.

Rough rule of thumb is to use 2 or 3 more PSI than what the tyre placard says, in most cases this will improve handling, braking, fuel economy and tyre longevity.

Then with lower profile tyres you need a bit more PSI again, roughly one or two extra PSI per reduction in profile, to keep the sidewalls 'tight' and prevent flex.

So on 40 or 35 profile tyres you should generally run 38 to 40 PSI. I run 38 in my 40 profile tyres.

KJ.

It says 32psi on the placard so that's what I've always inflated to. WTF? Should I be putting more in?

Damn right you should!! Never ever go by the placard as it is put there by the vehicle manufacturer and they put on a tyre pressure that makes the car feel "comfortable". I run 225/50/17 and I have 40 psi cold inflation in them. It does depend on which tyre place you speak to but if you are after better mileage and less distortion go with the 40 psi, it does give you a slightly harsher ride but also makes the steering a bit more responsive. This wont effect the wear on the tyre (as in overinflated wear). If you are after a comfortable ride then drop it down to 34 psi. I think 32 is a bit low though.

For best tyre life pressures have to be adjusted to suit driving style and vehicle characteristics more than anything. Also in very hot climate tyres needs more pressure and the less frequently you check the pressures the more you need to put in too as depending on the type of rubber some tyres can lose up to 1 psi per week.

For a heavy front heavy car like the 380 and Magna 36-38psi cold is a good starting point for the front and 4 psi less in rear when you aren't carrying a load. If you corner fast you probably need another 2-4psi all around.

Its a mistake to think low wall tyres need more pressure. In fact most have stiffer walls so adding pressure just gives them a lot rougher ride. Of more concern is a high wall tyre on a narrow rim. Without adding a lot more pressure the tyre rolls under when cornering and this tears up the shoulder tread. My AWD has 215/60 on 7" wheels and I need 40psi front and 36psi rear to get reasonable wear on the shoulders. They could do with more pressure but out in the bush where I live the roads are very rough and I'd kill the suspension and my back, and crack a few teeth if I went higher.

The 380 tyre placard says for 215/55 32psi front and rear, and add 7psi to the front for speeds over 160kph. So 39psi front and 32psi rear could be an alternative starting point.

Cheers,
Alan