So your tires have arrived it's time to put them on your trusty steed.
A quick stop to your local installer and her new shoes are on.
You take a second look at your new Yokohomas and are suprised to not see "ZR" on the sidewall.
You've got one of our top two Extreme Performance Summer tires and they're not Z-speed rated? What's the deal here?
Back in the day, high performance tires were all Z-speed rated. They were tested at some speed above 149 mph. In order to be more precise, tire manufacturers started testing at 168 mph (W-speed rating) and 186 mph (Y-speed rating).
In the above picture you'll see 91W to the right of the size. The W of the 91W means the above Yokohama Advan Neova is W-speed rated.
Since Z means 149+ mph, any W- or Y-speed rated tire is Z-speed rated.
You've got Z-speed rated tires after all.