Wheel/Caliper clearance question on the 981 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

MikenOH · 12-30-2012, 07:19 AM

Already posted on planet 9.

I'd like to use a set of 987.1 Boxster S wheels on a 981 S for track duty. The wheel width and offsets are nearly identical and I understand the 18" wheel will clear the calipers but with less clearance.

It's my understanding that the gap is about 19mm between the caliper and inside of the wheel; I measured my 19" stock rims on the 981S and the gap is roughly 30mm or a bit more.

Any downside to going with a wheel that will fit on the hub but not provide as much clearance between the caliper and wheel? Reduced brake cooling, maybe?

Thanks for any help.

thstone · 12-30-2012, 07:49 AM

I don've have any exact experience with the 981 but clearance is the only issue that I am aware to be concerned with. Maybe someone else can jump in to discuss brake cooling or some other issue.

In regards to clearance, be sure to check the clearance on everything, not just the caliper and remember that there will be some change in the relative alignment of some of the components when you are pushing hard on the track.

I have the slightly wider 996 rear wheels on my Boxster and I had a problem where the static clearance (car at rest) between the inside edge of the wheel and the shock absorber was fine but the wheel rubbed on the shock when I was driving hard on the track because of the camber change through the range of suspension travel (the wheel on the inside of the turn would experience negative camber and the top of the wheel now would rub on the shock). A wheel spacer was an easy solution to the problem.

Jittsl · 01-07-2013, 08:08 PM

I do not have any direct experience With 981 wheels either, in fact it took me a while to figure out what a 981 was, but.... My attitude would be if it goes on and doesn't touch anything and has a couple of millimeters clearance then it's good enough. I've never heard of anyone being concerned about cooling or any other issue.

blue2000s · 01-07-2013, 08:20 PM

Make sure it clears all of the parts of the brake. The bleed valves and the front of the caliper to the back of the wheel also.