Pilen Sport and Supersport, like its sister model, Pilen Lyx, have frames and forks in chrome-molybdenum steel SAE 4130. The Sports and Supersport models have frames with thinner materials and sleeker lines. The Sport and Supersport frames' top tube and down tube is of butted model, something you normally find only on racing bikes. strong>
Pilen Supersport and Sport has a frame with butted tubes of chrome molybdenum steel in the top pipe and down tube – thicker materials (1.2 mm) near the frame angles and welds and thinner materials (0.9 mm) in the middle of the tubes. It provides an improved relationship between weight and performance. Butted steel tubes was used in the classic racing bicycles era when the steel frames were dominant. No other manufacturer of classic utility and sport bikes in Sweden, Scandinavia or Europe uses butted frame tubes in chrome molybdenum steel SAE 4130 as far as we know.
You can hear the difference by the tone that rings when you strum with your fingernail against the frame tube. Snap alternating on the frame top tube near the seat post and compare with the tone in the middle of the tube. Are you musically overall, you hear it's a semitone. And it not only sounds good. The frame weighs about 4 ounces less than a similar frame without butted tubes.