Wheels, Tires & Pressure
 

I decided to put new 19” wheels and tires on my 2002 Boxster S, Michelin Pilot 4 S Fronts are 225/35 ZR 19 & backs are 265/30 ZR 19. I inflated to std front 29lbs and rear to 36, but was wondering, is this the right amount? Also, my previously correct speedo is now off 3 to 4 mph reading faster than GPS.

I know I’m not the only one with this wheel size and probably others have the same tire. What have you learned?

always use the tire pressure that is displayed for a car. Usually on the door jab but with porsche it's in the fuel cap door.

Expect your speedo to be off also, this is normal with going to a bigger overall diameter. Haven't seen anyone get it corrected for the 986. I now newer models it's something you can change in the OBC.

You couldn't get factory 19s on a 986, so Dan is wondering if the pressures he's using are correct since there won't be any labels. I do 32 frt, 37 rear with the 19s on my 987s, so you're close. You might bump your fronts to 30.

And all Porsche speedos run fast. They come that way from the factory. Your odometer is correct. Think of it as Porsche's gift to help you not get a ticket. However, if your new tires are taller or shorter than your factory originals, then you might change the speedo and odometer slightly. Taller will be slower speedo and fewer miles while shorter will be faster speedo and more miles.

Correct not factory wheels. Thanks for the feedback, will probably bump to 30 in front.