As you watch the video about stack and reach, you will notice a few things. It is looped to help highlight these details. We’ve have three static measurements, the stack, the wheelbase, and the top tube. Our independent variable is the angle of the seat tube, which is not represented by numeric values, but rather by a visual range. Our dependent variable is the reach.
Now, take notice that at the beginning of each loop the reach is at 367.01 mm. However, as our independent variable changes to a steep angle, the reach increases. At the end of each loop, the reach has increased to 404.56 mm. That is a 37.55 mm increase over the initial reach. That’s almost four centimeters!
Just imagine adding four centimeters to any distance on your bicycle. Would your new bicycle feel the same? The issue is most cyclists don’t notice these differences because they usually aren’t that drastic from frame to frame.
To be fair, this video is not the end all, be all for fitting geometries, but think about what happened the last time you bought a bike. You drove, walked, or strode down to your local bike shop and said you were looking to buy a new bicycle. The employee who happened to approach you, probably began by ask you a few questions. What are you looking to use this bike for? How often do you ride? Questions of that nature. They will next pull out a bike to have you stand over it to see if it’s the right size, then ask if you want to test ride the bike. Don’t misunderstand, this process is perfect for hybrids, kids bikes, and low-end selections. The point this video is making is that those processes are not bike fittings. They never take into account how long or short your torso is in comparison to your legs. This reach measurement is important because it helps place your abdominal muscles correctly while you are pedaling.
If you have any questions about stack and reach, or other aspects of bicycle fitting, come visit us at ATA Cycle or give us a call at 978 369 5960.