I haven't a knowledgeable say on this matter, as my rides over the past decades have either been full-sized pickups (too big), my diesel Golf (far too small), or the Model S. Those of you with experience in higher-end SUVs, like the Cayenne or Audi, however, may have some opinions on what tires may be best appropriate for the X. Or is is too difficult if we don't even have a firm handle on the rim size and width?A good start may be to assume AWD; as with any vehicle we could either assume all-season or summer & winter. My own belief is that a high-performance tire per se is not appropriate for an SUV - that's why you get a P85+!!! - but I also know others think differently. - - - Updated - - - Still can't create paragraphs or amend text. I guess I've been put on double-secret probation. Sorry!