The inset shows why the Interco TSL/THORNBIRD is such a Versatile tire. The highway contact area in the illustration shows the tread on hard surfaces. The Three Stage Lugs on the sidewalls do not touch highway surfaces but as soon as the tire gets into mud or snow the sidewall lugs provide decisive traction in forward or reverse. Fiberglass belts under the tread and polyester body plies contribute to a really smooth comfortable ride. The design comes close to being two tires in one... a revolutionary design that has earned its place in the legendary ranks of Super Performance.