I am looking for tires. and i was wondering if anyone know what the differnt in a Y and Z series tires? I call a tire shop and they said they got some KHUMOS Y series tires in stock. but i've been hearing Z series are better. can some one please tell me what the differnts between them or are they the same thing?

 

speed rating, one is like 145 and the other is like 156, but a y will last much longer cause its harder (most of the time)

 

Y is a subcategory of the Z speed rating. Y is rated for up to 186mph. Z indicates speed rating of 149mph+.

You can't go wrong with the Y speed rating.

 

Remember speed rating are for brand new tires tested on a lab machine at 70F with ZERO CAMBER ON THE TIRE.

Raising tire temperature or setting any negative camber greater than -0.5 degrees will make these test less useful.

As will having more than a few thousand miles on tires!

Tires are tested just after a 250 miles break in period and won't explode until a few miles per hour above rating.

They are tested with maximum load weight on tire so this buys a little since most don't load them quite that high.

 

^nice, so im safe with 160mph with my toyos.

 

Do you work in the industry? How do you know this?