I need some tire advice going from 18" to 19" wheels.

I am currently running 18" Michelin PS2 235/40 & 315/30 on 996.2 GT2 wheels.

I also have a set of 19" Ruf wheels, which are 11" wide in the rear vs. 12" for the GT2 wheels. I am considering getting a set of Michelin Pilot Super Sport 245/40 & 305/30.

Are there any issues with running the MPSS in those sizes?

 

Bump.

 

I run 19x8.5 and 19x11 RUF wheels on the street with 235/35 and 315/25 PS2s. This the size recommended by RUF

 

You need to look at tire height 26.3" for the 305-30-19 and 26.7" for the 245-40-19 in the Pilot Super Sport: http://www.tirerack.com/tires/tires....ot+Super+Sport

The 996 Turbo comes with 25" tall tires from the factory front and rear.

 

I would prefer to run 245 front and 305 rear since I have too much understeer with my current setup.

 

Stupid question, but why does it matter that they are taller compared to stock? I always thought that the main criteria was to ensure that the front and rear have the same diameter (or very close)?

Another reason why I would actually prefer the larger diameter is that I could slightly lower the car to close the gap between fender and tire. I have a steep driveway and can't lower it any further on my current setup.

 

You will have clearance issues with the taller tires rubbing on the fender liners especially in the front when turning. In order to decrease understeer, you need to dial in some addition camber in the front. I run -2.1 in the front and -2.0 camber in the rear along with a stiffer anti roll bar in the rear. Understeer is gone.....

 

Excellent information. I will look into getting 19" PS2 instead.

What anti roll bar are you using?

 

H&R. It's 24mm I believe and adjustable. I run it at the middle setting. It is quite a bit thicker than the RUF bar that was on the car. As you stiffen the rear bar you will be increasing oversteer, or in your case, decreasing understeer. Reducing rear toe in will also decrease understeer as it will make the rear more willing to "come around".. I run 1/16" total toe both front and rear..

 

Perfect. Thanks for yor help!

 

as an fyi you will notice a lot of road noise reduction with these tires.. its amazing what just a good quality tire can do.

 

which tires are you referring to? PS2 or PSS?