18 inch wheels on a MY97 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

RandallNeighbour · 08-07-2005, 05:09 PM

I'm puzzled as to what offset, bolt pattern, etc. I need for 18 inch rims on my 97 boxster. I know absolutely nothing about rims and need to learn all I can before I go shopping.

I also see that some owners have put 18's on their 97 and have no problems, but TSB's have been released saying this size rim or larger causes premature bearing failure.

Any info you all can provide to educate me on wheel sizes, offsets, etc. would be greatly appreciated!

YellowJacket · 08-08-2005, 12:06 PM

I know this doesn't answer your question, but if there are TSB's out against it, I would advise not to do it. I have a 97 w/ 17's, and I think they are perfect for the car. The ride couldn't be better.

Sorry to preach instead of answering, tho!

Brucelee · 08-08-2005, 12:21 PM

My service shop insists they have seen bent suspension on 97s that have done this.

I have no personal knowledge of it though!

Perfectlap · 08-08-2005, 12:49 PM

yeah stick to the 17's.
particularly If you have worn shocks and struts on that 97.
the ride can get very rough.
Get bigger rubber and add side skirts and it will round out the look quite well.

here's a pic of my 18's with the new skirting. No lowering springs needed.
I'm going to put the rear tires up front (245) and get 275's for the back once
the fronts are good and shreded at season's end.

RandallNeighbour · 08-08-2005, 01:13 PM

Since I posted this question, I found this on the PCA website. One guy says no and one guys says it won't hurt anything, go ahead...

PCA Q and A on 18 inch rims on a 1997 Boxster

I still have some general questions about rim sizes, offset requirements, and bolt patterns as well as tire sizes for my car's aftermarket rims. Anyone willing to educate me on these things?

Tire question: My 17's are aftermarket ROH rims (Australian rims designed for domestic cars for the most part). They are 17 x 7 in the front and 17 x 9.5 in the back if I'm not mistaken (I'm quoting this from memory, not staring at my wheels right now).

I last put 225/45's on the front and 255/40's on the back. The front tires are cupping at 10k and worn in the middle of the tire (always kept at 29 psi). Could a wrong tire size be the cause of this problem?

Pablito · 08-08-2005, 07:05 PM

I have a set of 18" Sport Design and needed 15 mm spacers to accomodate the rear rims on 265/35 tires....the ride is a bit rougher than with the 17". I believe the bolt pattern is 5 x 100 ...don't quote me on this...finally I also read from other sources that the 98' boxster was modified to support the 18" wheels....I'd very careful in going that route on a 97'