Creating a custom 9 speed cassette.
10-28-14 | 12:01 PM
#1
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From: North, Ga.
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Creating a custom 9 speed cassette.
I wish to create a 12-30 9 speed Shimano cassette for road use. Sheldon Brown says this is easily done by taking a 12-27 cassette, removing the 14 cog & adding a 30 cog. My question is regarding the resulting shift quality from the 13 tooth cog. If the original 13 is designed for a one tooth jump to the 14 & now has a two tooth jump to a 15 with that not cause problems? Can that be salved by using a 13 from the xt cassette? Is it more complicated than that? Thanks!!
10-28-14 | 12:10 PM
#2
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From: Somerville, MA and Catskill Mtns
I'm confused about the 30 cog swap. Aren't the largest few cogs permanently attached to the spider? It is my [limited] understanding that only the smaller cogs are removable and interchangeable, at least on the more expensive cassettes.
As for the shift quality-- the ramps are engineered to provide optimal shifting to the neighboring cog given a specific number of teeth difference, but in reality, it's not noticeably different if that tooth jump varies from the original cassette. Harris Cyclery used to make their own custom cassettes for customers based on their own preferred ratios, and I think they even mentioned on their website that the shifting is negligibly effected.
As for the shift quality-- the ramps are engineered to provide optimal shifting to the neighboring cog given a specific number of teeth difference, but in reality, it's not noticeably different if that tooth jump varies from the original cassette. Harris Cyclery used to make their own custom cassettes for customers based on their own preferred ratios, and I think they even mentioned on their website that the shifting is negligibly effected.
10-28-14 | 01:18 PM
#3
Thread Starter
Senior Member
Joined: May 2008
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From: North, Ga.
Bikes: 3Rensho-Aerodynamics, Bernard Hinault Look - 1986 tour winner, Guerciotti, Various Klein's & Panasonic's
I'm confused about the 30 cog swap. Aren't the largest few cogs permanently attached to the spider? It is my [limited] understanding that only the smaller cogs are removable and interchangeable, at least on the more expensive cassettes.
As for the shift quality-- the ramps are engineered to provide optimal shifting to the neighboring cog given a specific number of teeth difference, but in reality, it's not noticeably different if that tooth jump varies from the original cassette. Harris Cyclery used to make their own custom cassettes for customers based on their own preferred ratios, and I think they even mentioned on their website that the shifting is negligibly effected.
As for the shift quality-- the ramps are engineered to provide optimal shifting to the neighboring cog given a specific number of teeth difference, but in reality, it's not noticeably different if that tooth jump varies from the original cassette. Harris Cyclery used to make their own custom cassettes for customers based on their own preferred ratios, and I think they even mentioned on their website that the shifting is negligibly effected.
It's time to replace the cassette and chain. I want to try a 13 with two shift ramps this time and see if that improves shifting.
