Basically, you have to pile up money, shifter, cassette hub may not take a 10 cog cassette, so new wheel, re cabling..
then maybe you lust for a special new crankset...
9 by 1 is simpler you just remove the outer chainrings get a different one for the middle with full height teeth.
....
Last edited by fietsbob; 12-21-17 at 10:40 AM.