From Porsche Club of America:

LINK

Quote:
Question:
(1) What if any off crown drift/pull is considered normal or within spec for a Cayenne? When I purchased my Cayenne there was zero drift now with 3500 miles it drifts right (about 6 seconds from road centerline to road edge)same road, same speed. My dealer says this is normal. Although this drift is slightly annoying my big concern is tire wear. (2)Besides tire pressure, (they checked the alignment) what can I do to promote tire life. How often should I rotate the tires (19" P Zero Rossos)? I alway s thought Z+ rated tires were directional and should only be roatated frt to back or back to frt. My dealer says otherwise.

Thanks for your help

Answer:
Not all Z rated tire are directional. Some even say inside and outside. Directional tires are for channeling water out of the center of the tire when raining. We do get drift issues with the Cayenne, at 5200 lbs, if the road is not flat the car will drift, usually to the right or the low side of the street.
The only thing to do is to rotate the tires at about 10000 miles. The fronts usually go first, but you should change all 4 at once. So rotate them to get the wear even. If the tire circumference differential is too big, the transfer case starts making wierd clunking noises.

Peter Smith - PCA WebSite - 7/26/2006