Originally Posted by
eddy m
What problem are you trying to solve by ditching the rear derailer? IME rear gear changers work better than front, especially with triples. The added loss from 2 pulley wheels versus 1 is insignifcant.
+1 Front shifting under load is far more problematic than rear shifting. The major negatives I see with your proposal are:
1. The gaps between adjacent gears are going to be huge (46% from 26T to 38T and 31% from 38T to 50T) so finding a comfortable gear is going to be difficult particularly under varying road conditions.
2. Stopping to shift manually in back is going to get real old real fast unless your are in very uniform terrain.
3. A dishless rear wheel is not the great benefit it might have been years ago. Modern rims and spokes are much more durable and a moderate dish say 6 or 7-speed with 126mm spacing or 8/9/10-speed with 130 or 135 mm spacing) is no problem.