My road bike currently has a 12-25 cassette on it. I really want the cog with 11 teeth instead of the cog with 12 teeth, but I don't want to upgrade to a full 11-32. If I were to install a new 12-25 cassette on by bike, but replaced the 12 tooth cog with a 11 tooth cog (effectively creating a franken-cassette) would it still work? Or are the cogs in a cassette not made to be mixed and matched like this?

It's assumed that both of these cassettes would be general SRAM cassettes, but I'm not talking about cassettes like the XG-1190 that have "compatibility notices".

And as a follow up question, would I need to re-calibrate the shifting mechanism after having created this "franken-cassette"? The number of cogs would effectively remain the same, so I'm hoping not.

  • 1
    They sell 11-25 cassette. Are you not finding what you want? Correct you should not need to re-calibrate.
    – paparazzo
    Feb 12, 2016 at 13:18
  • Yeah, its possible, but the question is why, versus buying the Shimano/SRAM cassette which is 11-25 already? And on top of that, are you really spinning out on your 12 ?
    – Batman
    Feb 12, 2016 at 13:22
  • 1
    there isn't much difference between an 11 and 12 tooth cog. Assuming you are running a road bike with a 50 tooth chainring, an 11 tooth cog will make you go 51.7 KM/h at 90 rpm while the 12 tooth chainring will make you go 47.4 KM/h. Most people would struggle to make the bike go that fast.
    – Kibbee
    Feb 12, 2016 at 13:43
  • 1
    1 tooth difference between adjacent cogs is MOST noticeable in the smaller cogs. About 9% in this case. That would be like changing 3 teeth on the largest cog (such as 36 to 33).
    – David
    Feb 12, 2016 at 13:45
  • Are you riding 10 or 11 speed? I'm pretty sure sram doesn't do a 12-25 in 11 speed, but as frisbee said they do an 11-25, but it's 11 speed, at least mine is. I'd prefer to have the 12-25 because you get a better ratio up top where you're using it more, usually the 18 tooth cog. Rarely is an average rider spinning out an 11-53 or even a compact on an 11.
    – ebrohman
    Feb 12, 2016 at 13:50

1 Answer 1


absolutely, I do it all the time. just make sure they are sequential. (ie. 11t 13t, 14t etc)

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Gary.Ray
    Feb 15, 2016 at 4:45

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