Ok so I just purchased my tC a few days ago and now my light is showing that my tire pressure is low. I got the car used and they guy has the 17" upgraded rims with Pirelli Tires on them. Anyone know what the pressure needs to be for this setup?

 

Look on the tire...I don't know off of the top of my head.

I know for the stock 17s the ideal pressure is around 30psi.

But I'm not sure about the 18s.

 

32 psi for the front tires
29 psi for the rear tires

Open the glove box and push and hold the button to reset tire pressure for the ecu.

 

Make sure that is 30psi with a COLD tire though. Warm tires could be 5psi or so higher.

 

Never go by what is on the tire. As some have mentioned, go by what is on the door sill or in the manual. 29 Rear, 32 front.

What year model is it? If it is 2007, there is actually a tire pressure sending unit in each tire (if you swap rims.. you need those as well). If it is pre 2007 then it uses wheel speed to determine if one is low (turns a different speed).

In either case, check the pressures, make them right and use the reset button to turn off the light. If it comes back on then you can have the dealer look at it (or a private shop if there is no warranty left).

 

go by this, and when you reset make sure it flashes 3 times

 

Thank you. I was just going to warn not to use the tire. Those are maxium pressure measurements for those specific tires, not for the vehicle. For normal inflation, I always check the door. Even if you go with a different tire name, but still same symetry of the stock tire, you can just use stock pressure readings from the door jam.

 

Doesn't it give the recommended PSI on the tire? Or was that in the manual that I read that?

 

The tire will give the max pressure, and sometimes the reccomended. But the numbers on the car give pressure recommendations for the load that is on the car. On the tC the load is a 60/40 mix of 2900 lbs or so. So they recommend a pressure of 32/29 for the size tire that comes on the car. So for anything close to that size you should stay roughly at those numbers and percentages.

 

about 40 psi for autocross...jk

 

I have 19's 225/35. my tires say 40psi all around...so just look at the tire wall. it will tell ya

 

Again, NEVER go by the sidewall. That does not account for the weight of the car. If you run 17's or 18's, go by what the manual tells you for the car, period.

For 19's, it is tricky because you arent running reccomended size for the car. I would still run them at 32 front, 29 rear though. Or add a few pounds for lower profile tires, but still keep the same ratio front to rear.