I will be getting 18" for the track and I need a new tire for my stock class.

Many at my track and my club have recommended the Falken RT-615's.

The sizes that are available for our cars in 18" are:

Front:
225/45/18
235/40/18
255/45/18

Rear:
295/40/18
315/30/18

I will probably go with the:
235/40/18
295/40/18

Opinions and reviews welcome.

I haven't run the Falken tires, but will say that you should be running 315/30/18 in the rear on a 11-12" wheel, the 295/40/18 will be too tall.

but dont you need a taller tire to compensate for the 1" in diameter lost in wheels size?

Technically to keep the total diameter the same dont you need to:

19"
235/35/19
295/30/19

18"
235/45/18
295/40/18


These should keep the overall diameter around the same.

So going any lower profile will lower the overall diameter... ????

No it should be 295/35/18 and a 235/40/18 will get you near the same tire diamater. Going to a 40/45 series tire will make you about 1" too tall.

Keep in mind the above tire sizes I quoted are actual Pcar sizes used on 997's with 18" wheels.

If you are going to track the car though I would go with the widest tire possible such as the 315 that NorthVan recommended. Also go with the widest tire possible on the front ala. 255/40/18's on the front if you have the proper offset. You never mentioned what wheels you are going to be using.

I don't think that Falken makes the right size tire for your application.

Dave, I agree that the 295/35/18 is the better size, but good luck finding one for the track. I originally ran 18" wheels and tires at the track, and couldn't find the right tire sizes to work with the 997. I went to 19" wheels and run OEM tire sizes for the track.

As for a the 18 inch comparison of the two tires, here is a chart that will show you what your net results will be.

I much prefer the Toyo sizing...the Falken sizing is not as good...but they will work so it depends on the cost.

I use:
245/40/18
305/35/18

I also used 255/35/18 and 315/30/18...a little smaller diameter but sure did feel great and help with accelleration out of the corners.

The RT615 does NOT come in Porsche sizes. You can get the AD07 Yoko's or PS2's in 18's. I don't even know what stock class means. You can run any tire in any run group that you are signed-off for.

If you have an 11" rear wheel you can get the 315/30 to fit but it may rub without some serious camber

Agreed that size for a track tire is next to impossible to find. I agree with Mdrums...a 305/35/18 and a 245/40/18 with a set of R888's would be the way to go.

Dave

Yes, the 305/35/18 is perfect, I believe this is a new tire size and next to impossible to find Toyo888's in Canada.

How about the RA1's??

Dave

I have seen a few people with them. So I would assume that they are readily available. I am not sure about 997 sizes.

They have them im 245/305 sizing for 18"..here's the link.

http://marktg.toyotires.com/file/18968.pdf

Not many Toyo Dealers around here. I am sure that with some effort I could have them, however I am going to try Hoosiers R6's this year.

Let us know..aren't the Hoosier's sizes a little funky?

Dave