I believe these are S speed rated. If I recall correctly, these are the radial version of the Volkswagon Bug tires (hey this is HybridZ after all...), so maybe they are rated to 80 mph! Not sure about the aspect ratio either (my brand of tires never state this, I guess this is why they simply refer to these as "165 metric radials") but I would imagine these are about 165/85 or so. I run these on the street and track with no issues and 120 mph traps through the 1/8th. They do well on big wheelstands too (I couldn't really tell a difference between the cheaters in this regard). There is however a considerable difference in street manners in my experiences from the barely street legal skinnies, which to me made me feel disconnected from the car, especially when running cheater slicks out back on sunny days.. If you regularly drive your car on the street and are ever caught in the rain you will be glad you had these front tires. Good tread that sheds water well, I really don't care about the additional rolling resistance.... You will have to decide whether exceeding the speed rating is an issue for you... I would be interested in other's opinions about exceeding the speed rating, say through the 1/4 mile- I have other friends running the same tire, no issues and these are very quick street/track cars with different power adders and setups, several of these cars do still run the quarter with these tires. I don't run the quarter anymore anyway since I've been banned in Ennis for no license so I'm really not worried about a few MPH over in the 1/8th. There is a safety factor built in with the advertised speed ratings anyway. I looked for the highest quality tire I could find and these were still very cheaply priced tires in comparison to the drag tires and are cheap enough that I replace them yearly regardless of the mileage for added safety (for whatever that is worth).