Cannondale Trail SL 29er 4 2013 Mountain Bike. The affordable superbikes. With frame weights and technology that rival anything found on the World Cup race circuit just a few years back, the Trail SL series of bikes proves that you don't have to spend a ton to get truly exceptional performance. Available in both 26'' and 29'' versions, there's a Trail SL for every rider. All new frame, Completely redesigned for 2013, the Trail SL frames have a new lighter-weight frameset moulded after our high-end Flash frames, new lighter dropouts and more exaggerated SAVE features. Lighter, Stiffer and Smoother. Trademark double-pass smooth welds showcase Cannondale's aluminium frame mastery. Since Cannondale don't patch fill with putty and paint, their process eliminates the stress-risers and weak points found on traditionally welded frames, enabling Cannondale to build lighter, stronger frames everywhere in the line. 1.5'' Head Tube: The oversized 1.5'' head tube increases front end stiffness for better steering and control.