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I have a 2003 911 cabrio (no PSM) with the Carrera 18" wheels and need a new set of tires. I have decided on the Michelin Pilot Super Sports based on reviews and price. Unfortunately, they do not make stock sized rear tires (285/30 ZR18).

My choices for rear tires are:

285/35-18 - (taller) or

265/35-18 - (narrower)

My choices for front tires are:

225/40-18 - Original size

235/40-18 - Seen others recommend... not sure why

2 questions:

1) Which rear tire size would you recommend?

2) Why should I change the size of the front tires from the original size?

Thanks for you input.


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hey there. Tire choice is always a challenge somewhat. As I learned over the years from my own arrogance and stupidity , its really important to realize Porsche specifies components for a reason. This being said, your choices look correct for stock 18's.

What I discovered on my 2000 C2 RWD coupe was the total rolling circumference makes a difference on handling and comfort at speed. After playing around on a number of web based tire size calculators, I settled on 225 40 18 up front and 295 30 18 on rears because the difference on outside circumference was less than 1/16". I presume your rear rims are 11". but these would still fit on 10.5 rears.

The other aspect not mentioned is offsets. Again, I presume your rims are stock and ET's are 50 upfront and 65 at rear. 225's upfront give you 8 inches of rubber . For aggressive driving, they are more than enough to point the car in the right direction at normal street and highway speeds. 295's give you about 11.5-12 inches of rubber at rear. They look wide, are wide and act wide.

Not sure what environment you live in, but its worth looking at hardness too. Im here in Florida. Heat and rain are primary considerations. I like soft compound and am running Kumho SPT's all around. They're cheap, but well made. ( others may disagree ). The downside of any tire is wear. Im only getting about 9-10,000 miles on the rears, but I dont care. Id rather eat up tread then end up wrapped around a tree.

good luck. lets us know your decision. take some pics :-)

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I have an '01 996 Cab C2 and recently replaced my tires with the all new Michelin Pilot Sport AS 3(all season). I went with 225/40ZR18XL on the front and 265/35ZR18XL on the rear. I couldn't be more pleased with the choice. The grip is excellent and the price was right. I live in Michigan and planned on driving this winter on dry roads but we haven't seen the grass 12 weeks!

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2003 C4$. Previous '79 911SC. I've used many tire brands over many years. I've always run sticky summer tires as I live in a rainy, wet winter climate with no snow. Always look for the AA traction rating for wet weather driving. By far the best tires I've ever used are the Michelin PS2's, Porsche rated N3. No, Michelin is not paying me for posting this note.

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