Tyres Size on your SUBARU WRX STI CAR?

What do you mean when you say 185-65HR13?

185	65	H	R	13
This is the width in mm of the tyre from sidewall to sidewall when it's unstressed and you're looking at it head on (or top-down). This is known as the section width.	This is the ratio of the height of the tyre sidewall, (section height), expressed as a percentage of the width. It is known as the aspect ratio. In this case, 65% of 185mm is 120.25mm - the section height.	This is the speed rating of the tyre.	This tells you that the tyre is a radial construction. Check out tyre construction if you want to know what that means.	This is the diameter in inches of the rim of the wheel that the tyre has been designed to fit on. Don't ask me why tyre sizes mix imperial and metric measurements. They just do. Okay?