# Going from 12x25 to 11x25 10s cassette



## tjjm36m3 (Mar 4, 2008)

Was wondering if there's anything I should be aware of from going 12x25 (record) to 11x25 (chorus) 10s cassette.? Does the rear derauleur need adjustment or one less chainlink? I think the stackup height between 12x25 and 11x25 are the same. I'd noticed the 11t gear doesn't have a key slot in the center for orientation. I probably should align the 11t like the rest of them anyways. I'm going to make the switch this weekend and just don't want any surprises. I'm currently running a compact crank for the mountains here, but still need the 11 gear for the descents. Thanks in advance.


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## Guest (Dec 4, 2008)

You may need to adjust the rear deraileur a little bit, the chain is probably fine. If the chain is worn it may not run very smooth with a new cassette.


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## Keeping up with Junior (Feb 27, 2003)

*Lock Ring*



tjjm36m3 said:


> Was wondering if there's anything I should be aware of from going 12x25 (record) to 11x25 (chorus) 10s cassette.?


The lock ring for the 11t cog is smaller than the lock ring for the 12t cog. I believe the 11x25 cassettes come with the appropriate lockring while the 12x and 13x cassettes ship without a lockring and you should use the one that came with your wheelset.

The other thing you may notice is how much you actually used your 16t cog and how annoying the gap between the 15t and 17t is.


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## C-40 (Feb 4, 2004)

*info...*

The 11T cog does have the spline pattern that insures it can only go on one way. There is one very small spline that is the key to the timing - all cogs have it. The 11T lockring MUST be used, not the old 12-13 lockring or the lockring that came with your wheelset.

There is no change to the chain length, but if the chain has many miles on it, it's best to start using a new cassette with a new chain.

With a compact, you'll only notice the 15-17 jump when you're in the big ring. I noticed it at first, but apparently got used to it. Now I've got an 11 speed 11-25, with the 16T cog. I'm sure I use it, but I pay no attention to when.


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## tjjm36m3 (Mar 4, 2008)

C-40 said:


> The 11T cog does have the spline pattern that insures it can only go on one way. There is one very small spline that is the key to the timing - all cogs have it.


Hmmm... that's funny.... I'm looking at the 11T cog right now and it doesn't the spline pattern in the center cutout. It would make sense to have one on the 11T cog, at least to get the three modified teeth, for changing gears, on the cog to line up with the rest of the cogs. But looks like that's not the case with this chorus cassette I have here. 

Yeah luckily with all 11 spockets, campy provides the lockrings.


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## C-40 (Feb 4, 2004)

*???*

The splines on either side of the tooth at 12 O'clock are smaller than the rest. The cog only goes on one way.


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## tjjm36m3 (Mar 4, 2008)

Yup, you're right. I also looked at the campagnolo 10s sprocket manual and on Fig 7 it's shows the installation orientation.


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