Y speed rating is 186mph, what is the next letters? What do the 200+ motos use?
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02-12-2002, 03:22 PM
#8
Z existed before W and Y...so now you get both...
Z means 150+, but up to what number was the issue.
For example, Toyo Proxes T1S in 225x45x17 size is a Z rated, W speed index tire. So it's good for over 150mph, but up to 168mph.
On the other hand, the Bridgestone S03 PP in 225x45x17 size is a Z rated tire with a Y speed index. So it's good for over 150mph, up to 186mph.
As for which is better, i think it's safe to say that up to 168mph, both are within spec. At above 168mph in the Toyo, you are out of range for what the tire was designed for. So for those shopping for tires that can stay within spec at 170mph up to 186mph, you better buy the S03's...
At least, that's my understanding of TireRack's write up...
For example, Toyo Proxes T1S in 225x45x17 size is a Z rated, W speed index tire. So it's good for over 150mph, but up to 168mph.
On the other hand, the Bridgestone S03 PP in 225x45x17 size is a Z rated tire with a Y speed index. So it's good for over 150mph, up to 186mph.
As for which is better, i think it's safe to say that up to 168mph, both are within spec. At above 168mph in the Toyo, you are out of range for what the tire was designed for. So for those shopping for tires that can stay within spec at 170mph up to 186mph, you better buy the S03's...
At least, that's my understanding of TireRack's write up...
02-12-2002, 03:30 PM
#10
Y and W are basically new designations because Z is confusing
every other rating is up to, while Z is over, so W and Y were created. IIRC W and Y are still considered Z rated tires, just special new designations.