Originally Posted by
spelger
i think the chain being fed from the top would not permit that to work.
No, it wouldn't work.
Originally Posted by
spelger
im guessing that part of the reason why the RD shifts so much better and faster is that the number of teeth in adjacent cogs is only different by one or two, up front there is generally more than a 10 tooth difference between rings.
Yes, this is one of the reasons the rear shifts better. Smaller cog differences shift more cleanly (to larger ones, especially) than larger cog differences.
Originally Posted by
spelger
i wonder if the FD had more rings, say as many as an RD and if the cage were just a bit wider than the chain then shifting from one ring to the other might be as smooth as the RD.
I don't see being
wider helping. Shifting requires only one side or another. The reason it's not wider is to keep the chain in place. Wider would also mean more movement for the smallest and largest sprocket (making these shifts slower).
The idea of the front and rear is that one is for larger changes and the other is for smaller changes. If you make the differences smaller in the front, you'd have to make them bigger in the rear. You are talking about moving an issue (not eliminating it).
Originally Posted by
spelger
this is why i ask about crude, they both push the chain, the FD does it from the outside while the RD does it from the inside.
someone used the word guide but it is still being pushed.
"Guide" is a gentle push. The force of the pushing is very different. It's much higher for the front than the rear.