Along with all its other great ride qualities the excel has a reflective stripe on the sidewall, keeping you visible at night for city riding. If getting a reliable, high-performance trekking tyre is what you're after, the overdrive excel is the tyre for you. Silkshield offers protection from bead to bead whereas silkworm is found under the tread only. Silkshield provides an additional level of protection for sidewalls as well as under the tread. Reflective stripe on the side walls allow for enhanced side visibility, key for junctions and city riding. The most important part of a tire is arguably the rubber compound within the tread. By changing the amounts of various components of the rubber formula, engineers can make two identical looking tires perform completely differently. This tyre uses dual compound - two compounds used within the tread of select tires to offer lower rolling resistance and increased cornering grip. The function of the bead is to keep the tire in contact with the rim while the tire is inflated. A wire bead is a rigid metal wire is utilized as bead material in applications where ultimate strength is needed and transportability is not a factor.