Originally Posted by
fietsbob
9 is one more cog crammed in the space of 8, but since the indexing system
is at the opposite, head, end of the cable , you need to buy a new shifter..cassette and chain.
Math question , what gear ratio specifically are you missing in the 8 speed ,
that you see as necessary to switch the drive train over to gain that additional ratio.??
I think road riding without an 18 cog sucks and spent a few hundred dollars on the move to 9 cogs (a couple new freehubs, pair of lock rings, new index cam for my right shifter, new jockey wheels and bolts) when Campagnolo discontinued 13-14-15-16-17-18-19-21 which was my favorite cassette in the 8 speed era.
If I wanted one of the 11-32 wide-range cassettes being pushed as triple alternatives I wouldn't be happy with less than fourteen cogs in the form of an 11-12-13-14-15-16-17-18-19-21-23-26-29-32.
In between 10 cogs are the minimum needed to make 13-26/12-23/11-21 acceptable and 11 for 12-25 or 11-23 (Campagnolo doesn't do a 13-29 11 speed although that combination would work).
The astute observer will note that the bike companies are slowly giving back the gear options they took away by phasing out road triples to reduce SKUs and increase profits.
Too bad it will take getting 13 cogs to get back to where we were in 1991 with 50-34 x 12-13-14-15-16-17-18-19-21-23-26-29-32 just matching the range and spacing we could have with 53-39-26 x 13-14-15-16-17-18-19-21. Reaching state of the art in 1997 will take 50-34 x 11-32 14 speed to equal 53-39-26 x 12-21 9 speed.
The other angle is how much overlap you have between rings. While 50-34x13-14-15-16-17-18-19-21-23 9 speed has enough range to take a fit rider anywhere in the Colorado Rockies (34x23 matches 39x26 or 42x28) disregarding the fully cross-chained combinations there's only one cog of overlap (50x21/34x14) which leads to a lot of double shifting with the wrong terrain/wind/fatigue/rest day combination and it's right in the middle of the pleasant solo cruising speed range. An extra cog (10 total) or two would cut-down on that and on the big end would make for better chain lines and less drive train noise on most days.