18 rims on 1997 boxster

[js/sj]

I have read that 18in rims on a boxster is a bad idea. The frame isn't strong enough. The thing is the 1997 I am buying has these stock 18in rims on them. They came stock (premium rims). should I swap them out for 16in rims?

[ProjectM96]

Your source of information is false. The frame is very strong and stiff and wheel size does not affect it.
The Boxster came from the factory with optional 17 and 18 inch wheels. Many members here have put 19 inch wheels on their cars. The Boxster S only comes with 18 inch wheels.

[Ghostrider 310]

I'm pretty certain the largest size in 1997-98 was the optional 17" the car came with 16" standard. It is also true the car was reinforced in order to accommodate larger sizes in the following iterations.

[schoir]

I believe that there is a TSB that deals with this issue. IIRC, it says that 17" is the maximum recommended tire size for 1997 Boxsters. The rear frame was reinforced in 98 or 99 to permit larger diameter wheels.

Regards, Maurice.

[BYprodriver]

Originally Posted by js/sj

I have read that 18in rims on a boxster is a bad idea. The frame isn't strong enough. The thing is the 1997 I am buying has these stock 18in rims on them. They came stock (premium rims). should I swap them out for 16in rims?

Porsche warned against installing wheels larger than 17" when the Boxster was 1st available. When the 1998 model debuted most of the body from the front firewall to the rear was reinforced & Porsche announced it was safe to use 18" wheels. When the Boxster S debuted in 2000 it came with 17" wheels standard & 18" were optional. Later in the 987 production (2008-2009 I'm guessing) 18" wheels became standard on the S.

I have never heard of a 1996-1997 Boxster being damaged from running wheels larger than 17" but I would inspect all the sheetmetal surounding the engine before buying one.

[schoir]

Here it is, from TSB #4407, dated March 4, 1997: " Eighteen inch wheels are not approved for use on Boxsters. Use of eighteen inch wheels on Boxsters under severe conditions may result in structural failures of the body and/or suspension".

I guess the key here is "under severe conditions".

This caution was removed when the frame was reinforced in later years, but I guess that must be in another TSB.

Regards, Maurice.

[Aron in Toronto]

Originally Posted by schoir

Here it is, from TSB #4407, dated March 4, 1997: " Eighteen inch wheels are not approved for use on Boxsters. Use of eighteen inch wheels on Boxsters under severe conditions may result in structural failures of the body and/or suspension".

I guess the key here is "under severe conditions".

This caution was removed when the frame was reinforced in later years, but I guess that must be in another TSB.

Regards, Maurice.

This is similar to the info that I've read also, even though I use 18" wheels in the summer on my 97 w/o issues, but my driving style probably wouldn't be described as a severe condition. The PCA Boxster Tech advisor also wrote in his column that using 18" on the street would "probably" not be a problem, however using 18" (or even 17" R-compound tires) on the track may lead to trouble.