Forziii

Hi all,

I am in the process of waiting for my new rims and getting new wheels and it got me thinking about the tyre pressure.
I'm not entirely around why different cars have different tyre pressures and if the sizes change what it should be.

I'm aware that our car (AP1 atleast) recommends 32psi all around, but is that regardless of what wheel/tyre changes you make?
I'm changing from the AP1 16s to some work emotion 17s which are about half an inch wider in the front and rear, thus my tyres will also be a different size.
When I get them put on, should I continue to check them to 32psi? Or is there a different calculation that needs to take place?

I know it's a simple thing, but I just want to make sure I get it right!

Thanks

zeroptzero

The recommended tire pressure for the vehicle is the same regardless of tires and wheel sizes. Despite that I tend to run mine about 2 psi higher than recommended , so there is a wide range of pressures that you can choose to run if you wish.

B serious

Well...tire pressure for the same vehicle is dependent on tire sizing. A larger tire will have more surface area. 32 lbs per square inch is the pressure with tires that have the same volume as stock.

A larger tire will require less pressure to counteract the car's weight. A smaller tire needs more pressure.

Your spare tire is an example. Its drastically smaller. It needs 60psi rather than 32. Of course, construction and other things are factors as well. But volume is a big factor.

In this case, 32 PSI is likely fine. If one REALLY wanted to, they could take the volume of the new tires and compare it to the old. Then calculate how much the new tires should be inflated to by factoring in the car's weight.

But...again...AP1's and AP2's come with a 32psi spec. I'm guessing the tire volumes are very similar. The AP1 has a larger sidewall, but smaller numerical width. AP2's have a smaller sidewall, but larger numerical width.

B serious

Without any mumbo jumbo...32psi is a good spec. Go with that. Adjust if needed/wanted.

Saki GT

I typically run 33-34 psi in my tires, but it changes with the different tires I have on the car.

Forziii

Thanks guys.

I guess i'll run just over 32psi to be safe.
The tyres i'm getting won't be massively different from the AP2s anyway so i'll go 33-35.

Thanks