Can I build my own cassette?

[ahumblecycler]

Hello. I have been searching to purchase a used 11-25 Shimano cassette for a 10 speed drive train. I have only found full price 105 cassettes, but I have found 11t DA rings. I am currently running a 12-25 DA, and I want to know if I could insert a 11t ring and remove a different ring? If yes, what ring do I remove to maximize shifting efficiency?

[thwart]

Don't know about the S brands, but with a Campy 10 spd 12-25 cassette it is easy to just trade the 12 cog for an 11...

... of course, being Campy you then have to use a different lockring, made just for 11 cog cassettes. :rolleyes:

[Birddog]

Buy an 11/21 or 11/23. Use the lower gears from the new cassette and then top it off with the gears of your choice from your old cassette. Your likely result will be an 11/12/13/14/15/17/19/21/23/25.

Birddog

[palincss]

Are 11-21 or 11-23 cassettes any cheaper than the actual one the OP wants to end up with?

[Birddog]

Are 11-21 or 11-23 cassettes any cheaper than the actual one the OP wants to end up wit
I don't recall seeing an 11/25 10 speed cassette from Shimano. I don't believe they offer it but I could be mistaken. They are scarce in any case if they do make it.

Birddog

[RPS]

The newer DA 7900 offers an 11-25 cassette, as does the 105 line.

The following are the sizes available for DA according to Shimano web page.

11-21T, 11-23T, 11-25T, 11-27T, 11-28T, 12-23T, 12-25T, 12-27T.

[ahumblecycler]

I had been looking at the 105 11t-25t, but then I came across the 11t ring and thought "why can't I just do a little re-ordering of rings".

I think I may try it and give a report.

[thwart]

I've had no issues with my homebrew 11-25. But in all honesty I spend most of my time (I'm old and weak and it's hilly here... :D ) in the larger cogs. That said, never had any difficulty with shifting up or down from the 11 to the 13, and it does avoid spinning out on some of those downhills.

[torquer]

I had been looking at the 105 11t-25t, but then I came across the 11t ring and thought "why can't I just do a little re-ordering of rings".

I think I may try it and give a report.
Based on my knowledge of DA/Ultegra 9-speed cassettes, if you switch out the 12t cog with an 11, no problem, as long as you don't mind the 11-13t step. What you won't be able to do, however, is retain the old 12t outer cog as your second cog (since it is threaded for the lockring), so you will need a new 12t inner cog as well. 11t cog also needs a unique lockring, as I recall. Then you just remove whatever other inner cog you want, typically the first loose cog inboard of the ganged big cogs.

Then, of course, there's the whole issue of mixing used and new cogs, which may have significantly different amounts of wear, and the shifting issues that may create. But if your existing cassette is relatively new, this worry may be overstated.

[ahumblecycler]

Based on my knowledge of DA/Ultegra 9-speed cassettes, if you switch out the 12t cog with an 11, no problem, as long as you don't mind the 11-13t step. What you won't be able to do, however, is retain the old 12t outer cog as your second cog (since it is threaded for the lockring), so you will need a new 12t inner cog as well. 11t cog also needs a unique lockring, as I recall. Then you just remove whatever other inner cog you want, typically the first loose cog inboard of the ganged big cogs.

Then, of course, there's the whole issue of mixing used and new cogs, which may have significantly different amounts of wear, and the shifting issues that may create. But if your existing cassette is relatively new, this worry may be overstated.

Just got off the phone with my LBS (Joe @ Cycle City rocks!), and I placed an order for a 11t and lock ring. I am not concerned about the jump b/c the 11t (12t for that matter) is used downhill :)

Thank you to everyone who contributed to this thread! Have a great and safe holiday weekend!

[RPS]

I haven’t done it on 10-speed cassettes, but have done it many times on 12-27 9-speed cassettes. When switching from an 11-21 to a 12-27 for serious climbing, I’ve sometimes used the 11T and the shifting worked well enough for me. On a few occasions I simply replaced the 12T with the 11T which left me with the large 11 to 13 jump, but since I rarely use the 11T unless headed down a steep grade it wasn’t an issue.

A couple of times I installed both the 11T and 12T from the 11-21 cassette and removed the 14T (keep in mind my cassette was a 9-speed which doesn’t have a 16T cog). On the 9-speed cassettes the 21-24-27 are grouped, as are the 17-19. If I removed the first loose cog it would be the 15T which would leave an excessive large jump of 14 to 17. With this arrangement I ended up with: 11-12-13-15-(17-19)-(21-24-27)

In retrospect I prefer the simpler arrangement with the 11-13 jump since I use the 14T far more than the 12T.

I’ve used a 12-27 Shimano 10-speed which is very similar to the 12-25 but can’t remember the cog grouping. I “think” the 16T is loose, and if so, you could remove it and keep the 12T to even out gear spacing, but you’d have to also buy a new 12T cog as torquer mentioned above. Personally I’d leave the 16T in place and remove the 12T as you are planning -- may not be as standard but will be easier and you'll get more use out of it.