Can I buy an individual 18T Shimano cog?

[Stoeger]

I am still loving my LeMond, but I wish I had an 18T cog. I'll be riding 39x19 just over 100 rpms, switch to the next cog which is 17T and my rpms drop to under 90. The terrain around here is basically flat w/ slight elevation changes & a lot of times I'm constantly switching between 19T & 17T when an 18T would probably work better instead. Can I buy an individual cog or would I have to buy a whole new cassette? I have a 10 speed cassette, 12-25 & I'd ditch the 12T 'cause there is no way I'm ever going to spin it out.

Brian

[Tom Stormcrowe]

I am still loving my LeMond, but I wish I had an 18T cog. I'll be riding 39x19 just over 100 rpms, switch to the next cog which is 17T and my rpms drop to under 90. The terrain around here is basically flat w/ slight elevation changes & a lot of times I'm constantly switching between 19T & 17T when an 18T would probably work better instead. Can I buy an individual cog or would I have to buy a whole new cassette? I have a 10 speed cassette, 12-25 & I'd ditch the 12T 'cause there is no way I'm ever going to spin it out.

Brian
Brian, this would probably be better addressed in the Mechanics forum.

[CardiacKid]

http://harriscyclery.net/itemdetails.cfm?ID=800

[Bill Kapaun]

The 12T has a built in spacer. You would have to buy a new 13T for use as a top cog in addition to your 18T.
At that point, you might be better off getting a new 13-25. All new cogs!