Jeremy

This should be a relatively easy one - I am buying new rubber for aftermarket rims on my 01 996. The existing tires were put on by the PO and I don't believe they are the optimum size. The aftermarket rim sizes differ a little from OEM and are the following:

Front: 18 x 8.5 - 52 mm offset
Rear: 18 x 10 - 63 mm offset

Would you recommend I still go with the OEM tire sizes (front 225/40 and rear 265/35)? Thanks in advance for your response -

Jeremy

ivangene

285 in the rear IMO - I had 285's on 10 in wheels and it looked about right.. I think 265 looks a might bit skinny

Zookie

225/40F 285/30R is the correct Size for 996 NB With 8X18 & 10X18 Wheels

But if you have 7.5X18 & 10X18 Wheels then its 225/40F & 265/35R

soverystout

285s for the back and 225s for the front

Optical TDI

235/40/18 front since they are 8.5" and 285/30/18 out back. 265 will look stretched which I don't like, but some do. The only advantage to the 265 is that you will have more options.

Gaspasser19

So, you're saying if he uses a skinnier front wheel, he should get skinnier back tires???

Gaspasser19

+1

Zookie

no 235... You just cant go changing Tires Sizes its has to be in a certain perportion and parameters

I dint say that... Engineers at Porsche did, im sure they spent a little $,$$$,$$$.$$ coming up with those sizes, not just pulled them out of a hat you know

redridge

225/285 will be just fine... for the streets, get some adjustable sways for the track.

Gaspasser19

No, that's exactly what you said. Here, I'll quote you again:"225/40F 285/30R is the correct Size for 996 NB With 8X18 & 10X18 Wheels

But if you have 7.5X18 & 10X18 Wheels then its 225/40F & 265/35R"

Your first sentence is correct but you got confused in the second sentence.

8.5" is the front wheel width. 10" is the rear wheel width. With a 10" rear, the correct tire size is 285/30 18. The 265/35 18 is most appropriate on a 9" wide rear wheel. The 265/35 will fit on a 10" wide wheel but it will look stretched as others have said.

In addition, it is ok to use a 235/40 on an 8.5" wide front wheel (though it may rub a bit) in spite of what you said to Optical TDI.

Jeremy

Guys - I appreciate all of the feedback - I would like a more aggressive look, so would like to bump up if it will fit. Is there a concensus as to whether a 235/40 on an 8.5" front rim will rub? Thanks again.

Zookie

Again i did not make that Up, i quoted from Porsche TSB...

and FYI 265/35/18 Overall Diameter: 25.30 in 642.62 mm & 285/30/18 Overall Diameter: 24.73 in 628.14 mm... sooooooooooooooooo if you are looking for the "Streched" Look the 285/30 is a smaller tire than 265/35....

Optical TDI

Stretched is the width, not the diameter.

Gaspasser19

*SIGH* Someone else give it a try, I'm done. You, sir, are remarkably obtuse.

Philip P

wow...

a 285/30 is a WIDER tire than the 265/35. The sidewall on the 265/35 is greater than the sidewall of the 285.

SOOOOOOOOOOOOOO if you put a 265 tire on a 10" wheel, the sidewalls will be STRETCHED to make up that extra 20mm of tire. Compared to the 285 which will require NOOOOOOOOOOOOO stretch.