Brian, The C Line has a folding bead and no additional puncture strip, a combo not available in the Pasela for a long while now. Also, the tread band on the C Line is that of the 35mm tire on the 37mm casing, shaves weight only putting the rubber where you need it and increases the supple sidewall effect. There is a noticeable improvement in feel and weight from the 700×38 Soma New Express. Making a few tweaks to the overall design allowed Soma to get a high performing tire without the initial move to a new mold