Subaru WRX STI tire size
The most common factory tire size for the Subaru WRX STI is 245/40R18, on 10 of the 18 year and trim fits listed. Each year below lists the sizes its trims were built with (2015 to 2021). Pick your year and trim to see the tires that fit.
Check your own tire
A trim can be sold with more than one wheel size. The size printed on the sidewall of your current tire, or on the placard in the driver's door jamb, is the one your vehicle has.