|Ahead of the Rear Axle
|Behind the Rear Axle
Move the Seat Stay for A smoother ride? That all depends.
I've been told that by mounting the base of the seat stay ahead of rear axle that you get a smoother ride. I tried it, but I havenít noticed this to be true. I argue that given a static system (like this one), and given that the seat position remains fixed, when you compare the vector sums of both paths, those sums are in fact equal. In other words, the force that is transferred from your upper body to the frame is the same in either case, and is focused on the center of the rear axle.
It is very important to be aware of the seat position when testing this idea. The position of your body over the rear axle has a profound effect on the ride. The resultant tilting the seat forward when using the forward mounts could give the illusion of gaining mechanical advantage via the foreword mounts. I say "resultant" because in this case, when you change the position of the seat you change the geometry of the bike, thus shifting your weight.