Hello weenies, I haven't been around for a while.
After being annoyed by the rather large gap between the 15T and 17T sprockets, I thought I could jam a 16T in between them and drop the 11T to maintain 11 speed. I rarely use the 11T anyway, and a 16T would be far more useful.
Now, DIY project to follow. A lot of pictures and everything.
Time: ~1 hour
-11 speed cassette starting with 11T
-A spare 11S spacer or your devious substitute for it(more to follow)
-A spare 16T cog, which may be from any 10 or 11 speed cassette (more to follow)
-A 12T lockring
First I had to make sure of the feasibility of this project. So, I took some measurements:
16T cog from old 105 5700 12-27 cassette is 1.6 mm thick. The 13T from Ultegra 6800 11-28 cassette is also 1.6 mm thick.
Now I know the cog thicknesses are the same. The next problem to tackle is the extra spacer I need to put the cassette together. If you have an old 11 speed cassette lying around, use the spacers from it. If not, well, it's up to your ingenuity.
I had a spacer to adapt 11 speed freehubs to 10 speed cassettes, and I know it's 1.85 mm thick. I measured the thickness of the 11S spacer to be 2.0 mm.
Now, I need to add 0.15 mm to this spacer for the whole thing to work. I'll add the hodgepodge spacer as far down the cassette as possible so that I don't throw off the alignment of the whole cassette.
The sheet metal under the lockring seemed to be a nice candidate. I removed the sheet from an old 11T lockring and cut it so that I can fit it through the freehub.
2.0 mm, yay!
Now that I have all the components ready, I can put together the whole thing.
The wheel with all cogs up to 17T removed. Yes, it's an Ultegra 6700 wheel, adapted for 11 speed, which is a whole 'nother story.
Well, sh1t. No splines left for 12T to grab.
I believe this may be because I've cut the freehub just a bit too short when I was adapting it to 11 speed. In a dedicated 11S freehub, this may not be a problem. Anyway, I pressed on, hoping that the pressure from the lockring could push the 12T into the splines. I marked the 12T and 13T in the correct orientation and I will check them as I tighten the lockring.
Holding the 12T with a chain whip and tightening the lockring, I felt a THUMP which was the 12T finding its position in the splines. The 12T did not rotate further as I tightened the lockring.
Have not yet ridden the wheel. Gears shift perfectly well, can't see anything wrong as yet. Will follow up after a ride.
Sent from my Ultegra STI lever using gear cables