bidaci

I know the 6603 is for a triple front and the 6600 is a double front, but how much of a difference is there between the two and in what way do they differ?

Paul Y.

I've used a 6603 for 2 years. Love the smooth way it shifts. I never use the small ring. Sometimes I'll try it to see how its working. I would switch to a double but this works great and I think I would have to change too much. Everything is 9 speed crank is 10 speed (might not) but I'm not going to ask

ericm979

The left shifter has positions for three chainrings instead of two.

bidaci

Guess I walked into that one. To be more specific. The 6600 has trimming capabilities does the 6603? I have seen them both listed as 2/3 gear shifters, now maybe this is just for the 6000 series designation as a whole, or is it? Is the pull that much different? Can the 6603 trim? and if so is it a finer trim then the 6600 or the same?

Actually, why make two front shifters when really one unit could be made to do both applications?!?!?

fordmanvt

The only difference is the index positions. That is it.

Nashbar has the 6603 set on sale for $150.

calyth

My guess is with the indexing. You could adjust the limiters to prevent the chain from dropping towards the frame / out off the cranks, but the shimano allows multiple shifts to bigger rings, but 1 shift to drop to a smaller ring (IIRC, smaller paddle to drop to lower ring).
So then to shift on a double with 6603, you'd have to rapid fire on the small paddle to go from a large ring to small. I'd switch to a small when I'm going up the hill and the last thing I want is to have some finickyness to screw it all up.