dumb "wheels & tires 101" question
 

I'm presently on 17" Porsche wheels with the standard size tires (205/50 and 255/40) - what size wheels and tires can you go to in a bolt-on mode, i.e. no changes, no fender scrub, no problems. Doubt I would go beyond 18" rims, but what about width? I see some interesting wheel/tire packages out there, but not sure what would fit and what wouldn't.
When do the spacers come into play? thanks for the patience -

Well personally I would avoid spacers, but that's ony because I intend to track the car and attend some driving schools. Porsche naturally doesn't sign off on it.
But Spacers would be needed if you trying to retrofit a 911 rear wheel to the Boxster. That's a 10" wheel.
Better to stick to the Boxster widths. Check out Wheelenhacement.com they have a very good menu of wheels that will fit and they will answer any questions via email regarding spacers and lugs.
Just a quick note, if going bigger (18") try to get a light weight wheel. You'll get the looks without any big change in ride quality.

While we're on this topic, do the 18s that come on the 987 fit the 986?

I have a set of 18" wheels, 8.5" in front and 10.5" in the back, presumably with standard Boxster offset, although I've not measured them.
The additional width is mostly because of a "lip" to the outside of the wheel. You can see it, particularly on the rear wheels, in the picture, above. No problems with rubbing, etc.
I'd tell you what brand they are, but I have never been able to find any identifying mark(s), so I don't know. They are a single-piece alloy wheel, Sport Design style, but not factory wheels.

I also have a set of 18" rims, 8.5" wide in front, and 10" wide in back. No spacers. Mine are Gemballa Competition rims made by Speedline. I have no problems with rubbing and they fill out the wheelwells nicely. Your higher end wheel houses can give you the proper offset measurements so that you don't need spacers.

Thumper & Ronzi - thanks. What size tires did you go to?
Perfectlap - checked out Wheelenhancement - good site, lots of choices.

I just went with the Porsche factory recommendation for 18" wheels.

225/40/18 front

265/35/18 rear

I went with 245's in the rear on my 18x9 Carrera 5 spokes. (225 up front).

The tech over at Frisby Race Tire felt the 265 would have been too much for track and Autocross. Being that they sell allot of race tires like Hoosiers and Kuhmo Victoracers I went along with his recommendation.

Ditto to the sizes Thumper mentioned.
Not an autocrosser, so overtire-ing the car is not a issue with me.
From the back, it looks like the car is mostly tires and exhaust pipe.

What year is your Box'? Apparently, '97s don't take well to 18" rims. Search the board, but I remember a recent thread in this forum detailing the problem. If your car is not a '97, fogetaboutit, it doesn't apply to you.

Actually, you can get 5mm spacers from Porsche for the Boxster. The anniversary edition comes with spacers.


-