Jan Heine wrote:
> The problem only occurs with Shimano derailleurs. Shimano derailleurs
> are designed to shift under load, but to do so, they "wait" until the
> chain reaches a ramp on the cassette. As a result, you don't get
> immediate feedback when you shift, simply because the shift does not
> happen immediately.
>
By my calculations, at a speed of 10 mph, a wheel with an outside diameter of 26 inches will be spinning at a rate of just over 2 revolutions per second. The derailleur wait until the hyperglide ramps are aligned would have a maximum delay of .5 seconds. I question whether this make any perceivable difference to a human rider.
I think Sheldon's theory is more correct. With modern Shimano derailleurs, hyperglide ramps, and a friction lever; there is much less audible feedback than with older gear. Another big factor is that when the chain moves to another sprocket, it does so very smoothly. But this gets to the heart of the reason that I like this setup so well - it runs almost without noise!
Jack Fortune
Eugene, Oregon USA