I need to order 2 Y rated 245/40/17 Pilot Sports, but unfortunately Tirerack says availability on 8/31/03...would the Z rated version be an acceptable substitute? The fronts will remain the Y rated 225/45/17 Pilot Sports. I guess this may seem like a dumb question, but other than the higher guaranteed speed limit on the Y rated tires, would there be any real difference between the Z & the Y? Are the Y rated tires constructed THAT much better than the Z rated tires to deserve the higher speed rating? Thanks for your help!

Bump...does anyone know if it matters mixing Y & Z rated tires?

you will be fine mixing those 2 tires ..... the "Z" rated version just hasn't been tested to 186 mph

use this link to order your tires

Thanks Luke! I will order them today.

Either use the link I posted or give me a call and I will make sure everything is taken care of ASAP