It has finally happened! Some of the bigger players have joined up and suggested a new standard in bike sizing, which means that we can finally leave behind the old fashioned standard that is irrelevent for most mountain bike frames. I have never believed in using the seat tube length as the guage for frame size, as for a lot of freeride or downhill bikes this just doen't make sense, as you are not in the saddle much of the time when really riding.
The new standrad of reach and stack being proposed makes more sense to me. So we are going to add these values to our geomery tables in the near future. I still feel the need to include the old style geometry, as angles are also very important, and for some riders so is the seat tube length. It will just be another tool in addition to more exact geometry to help people choose the right sized frame for them.
The reason why reach and stack dimensions are important to any bike where you standing out of the saddle... because essentially these are your 2 points of contact with the bike... pedals and handle bars. Therefore the geometrical relationship between the 2 kind of gives you the 'feel' of the geometry of the bike. sure it excludes inportant informaion like head angle and seat angle, but it can be used as a guage to select the size of frame best suited to you after you have looked at the overall frame geometries to choose the best frame for your needs.
A step in the right direction!
