[Kaboom]

I know that there are things which are very close, like the 12-21, but does anyone make something with a 1 tooth increment each time? sth like a 11-19 or a 13-21 that still shifts as all the other official stuff out there? on my next setup i'm going for a tripple and a straight block. I am a climber, but there are a lot of flats where i live, and not having the right gear irritates me. Any ideas?

 

[torquecal]

http://www.sheldonbrown.com/harris/k7.html

Take a look at harris cyclery. Not sure if they already have a perfect corncob but you can buy individual cogs and spacers.

I know that there are things which are very close, like the 12-21, but does anyone make something with a 1 tooth increment each time? sth like a 11-19 or a 13-21 that still shifts as all the other official stuff out there? on my next setup i'm going for a tripple and a straight block. I am a climber, but there are a lot of flats where i live, and not having the right gear irritates me. Any ideas?

 

[Straightblock]

Do the math. The gear you're missing with a 20 cog and the big ring is duplicated with the middle ring and a 15 or 16. With 27 speeds, you're going to have some other duplicates, too.

Most of us, unless we're racing in fast packs, have no use for an 11 cog or even a 12. Just buy a 12-21, available in Dura Ace or Ultegra, or 13-23, available in 105. Either one will give you a straightblock up to 19 teeth. Particulary with a triple crank, you shouldn't spend a lot of time cross-chaining in the big ring & 2 largest cogs anyway. The extreme chain angle puts a lot of wear & tear on the driveline. When you get that far up the cassette, it's time for a double shift to a smaller chainring. Besides, if you really need a triple crank, you might occasionally find that having that extra couple of teeth on the back more than offsets the coolness factor of a tight cassette.