gophilip said:
On fast descents, my weight is carried mostly on the pedals at 3 & 9 o'clock. I think this helps lower the center of gravity & creates a more stable ride.
I dont know how to do the tuck downhill with the hands on the bar, close to the stem & fear learning this technique because of old age.
Is this idea correct or is it dangerous?
Yes, the cranks should be at 3 & 9 o'clock, but for other reasons. You really can't lower the center of gravity of your legs anyway, since whenever one leg is up the other down, so the center of gravity of the legs stays around the same place.
The reason for keeping your legs at 3 & 9 o'clock are threefold: Firstly, it decreases the overall frontal area of the legs, especially if you keep your knees pulled into the frame (tought to do with one leg down); Secondly, it allows one to "absorb" bumps and rough pavement with the bent legs by unweighting the saddle; finally, it allows one to keep a knee (or two) pressed against the frame to quell vibrations in the frame (and can stop or prevent shimmies).
Tucking with your hands by the stem can decrease drag, and is a technique that is not that difficult to learn. The geometry of a bicycle makes it more stable at speed, so at descending speeds very little steering input is required to keep the bike on its path. Practice by riding on the flats with your hands by the stem, and try some shallow downhills, and finally graduate to some steeper downhills. But at the same time, practice being able to move your hands quickly to the drops and the brakes.
Riding downhills with my hands near the stem is my preferred position, and I've descended at speeds up to 50mph this way.
