You can find many useful information on the sidewall of your tyre. At the end of the sequence, you can find a letter - in this case a W - which is the speed rating indication. For example, a W speed rating means the tyre can go up to a maximum speed of 168 miles per hour (270 kilometers per hour). The tyre maximum speed can be determined by looking at the speed rating letter on the sidewall and see what speed it is associated with, using the table below.
The speed rating is typically found right after the load rating, following the tyre size.