12-25 vs 12-27 Shimano

Swapping cogs around like that, if possible through mixing and matching bits of different cassettes, will result in shifting not as good; the ramps on the cogs are designed a specific way to facilitate easy shifting from one cog size to another. Mixing the cogs will mess up the ramp profile. It probably won' t matter much though, the shift might just sound a little clunkier.

I would say it's not worth the bother, even if you do find a place that will sell you individual cogs, you could have probably bought a cassette on sale from some place instead for a similar price, and save yourself a lot of hassle.

If the price of cassettes bothers you, remember Shimano 9 speed stuff is all interchangable; e.g. you could use a cheaper Tiagra cassette on your otherwise Ultegra equipped bike.

Food for thought: how about a 13-25? I hardly ever use 53x12 and would rather that for closer gearing.

Or else you could meet at the middle of your 25 vs 27 question, and get a SRAM 12-26 road cassette (which has the same gearing as a Shimano 12-25, just with a 26 big cog instead)

Quoted post said:

Originally posted by rek
Swapping cogs around like that, if possible through mixing and matching bits of different cassettes, will result in shifting not as good; the ramps on the cogs are designed a specific way to facilitate easy shifting from one cog size to another. Mixing the cogs will mess up the ramp profile. It probably won' t matter much though, the shift might just sound a little clunkier.

I would say it's not worth the bother, even if you do find a place that will sell you individual cogs, you could have probably bought a cassette on sale from some place instead for a similar price, and save yourself a lot of hassle.

If the price of cassettes bothers you, remember Shimano 9 speed stuff is all interchangable; e.g. you could use a cheaper Tiagra cassette on your otherwise Ultegra equipped bike.

Food for thought: how about a 13-25? I hardly ever use 53x12 and would rather that for closer gearing.

ya at 13-25 has youre 16t cog too. an ultegra cassette is only 45 bucks more or less.
Or else you could meet at the middle of your 25 vs 27 question, and get a SRAM 12-26 road cassette (which has the same gearing as a Shimano 12-25, just with a 26 big cog instead)

ugh

ya at 13-25 has youre 16t cog too. an ultegra cassette is only 45 bucks more or less

Quoted post said:

Originally posted by serenaslu
Well, after much deliberation I finally decided on a new ride an plopped down plastic on it this afternoon. Now after wracking my brains on that, I find myself self-debating on what to settle on for the cogset while the LBS is waiting on getting a longer stem in.

I have been riding (13-24)x(42-52T) for years. The bike is already built up Ultegra with 12-23 (39,53T). As I am getting a bit older I told them to swap it for a 12-27. Now I am starting to back track and think that I may be better off with 12-25. (Yeah I actually would be happier having the 16T-cog as well, so if anyone wants to send me the cash for the upgrade to DA-10 😄 )

So...

As I know that the largest two and then next three cogs are on common carriers, is it economically viable to convert from a 12-17 to a 12-25 (or vice versa) or would this exercise just come close to paying for a new cassette?

Also if there is any experience/advice on which would be better for rolling terrain/flats with some but fairly infrequent steep climbs.

I agree, a 12T cog is seldom used. That's why I opted to use the M10 cogs from Mavic. It's a set of 12 cogs and 2 sets of spacers wherein you can choose to use it for a 9 or 10 speed drivetrain (yellow for 9 and black for 10). It comes with 13,14,15,16,17,18,19,21,23,25,26 and 27T stainless steel cogs and its HG compatible for shimano pawl carriers. Have been using it for more than a year now on my campy record 10 speed drivetrain with campy 10 chain and mavic ssc wheelset.
If I go on hilly rides I'll use the 13-27T combination but normally it's just the 13-25T.

Works fine so far and it's like buying 2 cogsets-in-one!

Think of it this way... not that long ago, you would've been restricted to just 5, 6, or 7 cogs. Having 9 or 10 is a bonus. Why worry about a tooth here or there?

Back in the day, we seemed to get along just fine with 5. (That said, I love my C-10!).

Oh, and if you think a 12 is rarely used, wait 'til I get my Powertap wheel built up that HAS to use an 11 tooth cog because it's Campy on Shimano...