Originally Posted by
Reynolds
Good link but Dave Moulton should discover the difference between mm and cm. His bike's 10" bottom bracket height is 25.4
cm, not mm. That error is repeated throughout his blog.
Anyway, several years ago I did something similar to convert a 12x27 Shimano 9-speed cassette to a more useful 13x27 by removing the OEM 12 and 13T cogs, replacing them with a first position 13T and adding a 16T cog with spacers. That gave me a 13,14,15,16,17,19,21,24,27 sequence and included the very useful 16T and deleted the useless (to me) 12T. The problem with doing that now is that Shimano 16T single cogs in either 8,9 or 10-speed form are nowhere to be had.