Quoted from tirerack.comWhen Z-speed rated tires were first introduced, they were thought to reflect the highest speed rating that would ever be required. Since that time the automotive industry has found it necessary to add W- and Y-speed ratings (indicated in the tire's service description) to identify the tires that meet the needs of new vehicles that have extremely high, top speed capabilities.
While all Z-speed rated tires are capable of speeds of 149 mph and above, prior to the W- and Y-speed ratings were identified in the service, how far above 149 mph was not identified
I heard that the (W & H) rated tired last longer, is that true? I purchased the 18 inch Yoko Paradas and they only had them in ZR. Now, I'll never go ip to 140mph, hell I'll never go past 75mph. Old cats like me (30yrs old) criuse,pimp, high sign,and creep when I'm on the seen. My only race ended at 50mph against a neon. LOL!!!! My point is if the Paradas had an HR rated tire, I would have bought them. But I aint mad.kopper187 said:ZR is rated for 149+ mph maximum.
WR is rated for 168 mph maximum.
YR is rated for 186 mph maximum.
Quoted from tirerack.com