tetmtb1Tom Teesdale has been building mountain bikes for about as long as there have been mountain bikes around. Tom's experience, gained from building for such companies as Gary Fisher, Kona, Marin and Dean, means you will be getting one of the best mountain bike frames available. Because there are more than one type of mountain bike rider, Tom offers more than one type of mountain frame. The TomET is a cross country racing rig, with geometries that were developed on race circuts around the world over the years, for performance oriented riders. The TomET Touring is a more practical design for riders going into the backcountry, camping or commuting. The Expedition version has seen many fully loaded, self supported off road rides and come back for more. How does Tom measure a mountain frame? Seat tube length is center of bb to top of seat tube. The top tube length is measured...are you ready?... from the center of the headtube 30mm below the top of the head tube to the centerline of the seat tube, level to the ground. Since the top tube slopes on mtb frames the point you are measuring to on the seat tube centerline will be above the frame someplace along the seat post. A word about head tube length. Traditional road design locks in the head tube length because of the level top tube design parameter. The length of the head tube on mountain bikes is set by the designer. If you look you will see the TomET geometry gives head tube length for each size using a 424mm long suspension fork. When ordering a mountain frame please let us know what length fork you will be using so we can adjust the head tube length accordingly. For info on how to measure for frame fit see proper fit.