Originally Posted by
LessTruckMoBike
Drew-
I understand what you mean about the shims, but when you say narrow cassette, do you mean narrow range?
Yes.
I made the mistake of switching from 50-40-30 x 13-14-15-16-17-18-19-21 eight cogs to 50-34x13-23 9 cogs because it was the same spacing, same range, and two rings are better than three.
I shifted the front derailleur 10X more. Any time I sped up over 18-19 MPH in 34x14 for more than a brief small-ring sprint I shifted five cogs to 50x19. Any time I slowed down below about 16 MPH in 50x21 I shifted five cogs the other way to 34x15.
And I just can't abide a triple, unless its a tripel.
You can get similar range, spacing, and front shift frequency running 2x11 or 3x8; although 2x11 will cost more.