Question about Michelin Pilot Sport PS2 tire models

[DoooDahMan]

Hey all,

I got a flat last night. I am looking to replace one Pilot Sport PS2 that came on the car and I noticed that there are four or five 255/35 19s available. Some are ZR19 and some are R19. The Michelin site says that the "Audi" one is the "R19", but mine are all "ZR19". They all say they are Y speed rated. Is there any functional difference? Or will they all be interchangeable if I need to replace only one? I am concerned that my local tire guy will only have access to one of the available models.

Also, any real concerns about just changing one? There are only 10,000 miles on them and they still have a ton of tread left.

Thanks!

[Doc@tirerack]

Each version of the tire has been modified slightly to meet whatever the specific car manufacturer wants in the tire. Michelin considers these modifications to be some kind of corporate "secret", so we don't know the differences between the tires. All I can tell you is that we will often see one version of the tire with fewer reinforcing layers than another, or more sipes or even wider tread blocks than other PS2's, so its important to match the Audi version exactly. With Quattro, we would not want more than 3/32" tread depth difference between the tires to be safe. Normally we'd have you get a tread depth measurement of the tire and we can shave the new one down to match for $25. Give me call if you want the correct tire !