Originally Posted by
rpenmanparker
Use your own brain. Does it make sense? No matter where you put the saddle, if you sit on it no hands, your weight distribution on the saddle will be almost exactly the same. Maybe a small difference for how your legs interact with the pedals, but all your weight is on your butt. Now put your hands on the bars. The distance to the bars and slope of the torso will affect how much weight you need to support with your hands, arms and shoulders. That is why you move the bars with different length stems. You don't move the saddle for that purpose. The saddle is fixed by pedaling efficiency considerations. But wait, I've said that before.
Heres the big issue, this is wrong.
Originally Posted by
rpenmanparker
First of all there was no saddle, remember? This was on a chair. Second, so what? I keep asking, so what. Managing weight on the bars depends much more on where the saddle and bars are with respect to each other than it does on where the saddle is with respect to the BB. There is too many more important factors in saddle placement than balance. When you get those right, then you can set the bars. Balance is just not the main issue.
Balance is very much an important consideration and saddle setback plays a major role in this. You are balancing flexibility/aero/fitness.
Originally Posted by
rpenmanparker
The distance to the bars and slope of the torso will affect how much weight you need to support with your hands, arms and shoulders. That is why you move the bars with different length stems.
But for the same distance to the bars and slope of the torso, the saddle position dictates how much weight needs to be carried by the hands/arms/shoulders. For example, with 20mm of setback and a 100mm stem, you will have a certain amount of weight on your arms. If you decrease the setback to 0mm and used a 120mm stem you will have more weight on the arms for the same arm and torso position.
Originally Posted by
rpenmanparker
You don't move the saddle for that purpose.
Agreed, but that doesn't change the fact that saddle setback plays a major role in your weight balance
Originally Posted by
rpenmanparker
The saddle is fixed by pedaling efficiency considerations. But wait, I've said that before.
If the goal is to ride as fast as you can then the saddle position is not fixed, it is balance between pedaling efficiency and aero. Think of your position as a pivot around the axle. To keep hip angle the same when lowering the bars you have to decrease setback and raise the saddle a corresponding while increasing the stem length. This increases pressure on the hands and is a tradeoff, yet many pros are doing this now that the UCI has relaxed restrictions on saddle tilt, just look at how many zero setback seatposts you see in the peloton today and look at fit evolution for seasoned pros. If you don't change seat position because you think it is fixed for pedaling efficiency, then you have to close up hip angle to achieve the same aerodynamic position.