Over a month ago I noticed a little crack on my front tire (side) , I did not pay attention to it becuase it was about an inch long ,but this morning there was a crack that cover the whole tire and it was about an inch deep. What could 've cause this ??? I am glad I noticed before something happen. :(

did the car sit for a long time? Sounds like it dry rotted or something. Maybe that is tread seperation? What tread rating are they and how fast have u been on them?

I have toyo's rated Z The fastest I have gone is 80 or 90 mph . I drive the car daily. so no idea what happened :rolleyes

how much are you lowered? Maybe the inner fender cut into it when the tires rubbed if you are really low. Doubt the fronts would do that tho. You'd have to be really low. Probably ran over something.

what are the "h" rated tires good to? 130? i hope so cause i get to 120 or 130 on a daily basis.

oil would cause your tire to crack like that if it isn't cleaned off.

How about that stuff that is used to shine the tires ? I use a lot of that on the summer

H's are rated at like 130 according to tires101.com

tire shine will cause your tires to wrot away. speed ratings aren't actually for speed. they tell you how the tire is constructed. the speed limits they're associated with was for the government.