My coach and I had the discussion of weight back, dropping heels on day one. He said nope.
We spent that AM on very gradual descents and worked our way up as movement patterns allowed.
When I got home I watched a bunch of UCI footage, mainly XC - and if you have ever seen a UCI XC course few recreational riders could clean it, much less race it. What you see:
- Hips may shift back a few inches, but in no way off the saddle.
- Pressure on peddles stays in pretty much the same place.
- Weight is universally balanced on the bike.
What I found with my coach was that my descending posture was all wrong - weight too far back. If anything, my weight needed to be far more forward, and my chest far, far lower. It felt like I was doing this until video-analysis time. Then I saw what I really looked like.
When you weight is centered my coach said that the bike should just feel loose underneath you. He practiced this with me in a stationary position, so I could familiar with it. It is one of the things that I am sessioning now. It is extremely counter-intuitive to be that far forward, but once you lower youtr chest, it falls into place. When it is right the feeling of riding tight switchbacks is effortless and fun on a different level. A good analogy might be your skills journey in skiing, working with coaches and instructors; learning how to ski from your feet up, and directing your skis instead of pushing them - it just becomes effortless.
And the journey continues...