The letters “BSW” found on a tire sidewall indicate that it has a black sidewall. This designation simply specifies the color treatment applied to the tire’s side. For example, a tire labeled “BSW” will have black rubber visible on its side, as opposed to having white lettering (OWL) or being entirely white-walled.
Knowing this code helps consumers understand a tire’s aesthetic appearance before purchase. This specification is important because appearance can influence a vehicle’s overall styling. Historically, sidewall designs have been a key element in vehicle personalization and expression, with various treatments signifying different eras or styles of motoring.