Anyone any experience with these? How well do they work? Any creaking/slippage?

Also, is it as easy as it looks in the Niner videos to swap the non-eccentric inserts in and out?

Ta,

Andy

I have 2 bikes with them a One9 and a Sir9 and a first gen Sir9 with the old style bb. The one in the One has been flawless. The one in the Sir had some initial problems (and was the first generation) and Niner replaced it with a 2nd gen and it has worked since then. I also have not had any problems with the First gen Sir with the old style bb.

That said, I would not bother converting a bike that the bb was working well in. My old Sir is just fine and not really much harder to adjust. I would not hesitate to buy a bike/frame that had one in it.

One other thing. If you have it in a steel frame and you don't move it for over a year (my newer Sir is set up geared and I never have to move it much) over time the steel can rust a little and it can get hard to turn. This could be true with anything in a steel frame. With the old design, you can just hit the crank arms with a rubber mallet to free things up, but I had to loosen up the crank arm which actually clamps the entire bb to get the one on my Sir to move when this happened. So if you move your bb very often the CYA is probably the way to go since it is a little easier and does not suffer from left right alignment issues. If you hardly move yours then I would stick with the old style if it was working.

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For certain parts stiffer is more important than lighter.

If you don't mind me asking, what stops the EBB rotating? Is it the bolt holding the two sides together, or the BB preload?

Andy

The bolt clamps the sides of the CYA against the outside edges of the bottom bracket of the frame. The major change from the early CYA to the 2nd gen; the bolt seat was milled so that the bolt could be torqued to a higher torque spec without distorting the area around the bolt hole. This is also why the installation instructions require the removal of any paint from the edge of the bb on the frame since paint has less friction than bare metal.

One other consideration is crank choice. My geared Sir has a Shimano crank and Shimano cranks actually preload the bearings through the bottom bracket which will make CYA's with Shimano cranks a little harder to rotate. My other cranks are SRAM and they preload between the left bearing cup only and therefore exert no clamping force on the overall bottom bracket. The Shimano preload force is small, but it does make that CYA noticeably harder to rotate than the other 2. I have been way happier overall with the SRAM system including the fact that the left arm is self extracting and that there are no special tools required and they seem to have way less friction when spun without a chain attached.

I change gearing a lot on my One9 (19,20,21,22 depending on time of year and course) and I really like the easy adjustability of the CYA. I almost never change anything on my Sir that is SS with the old style bb. I have a 32 and 34 on the front and a 20 and 18 on the back and either use it off road 32x20 or on road 34x18 so I generally just move the chain on it and only have to move the bb as the chain stretches. My geared Sir has the XT crank and while I seldom move it (and now that it is the way I like it, I might never move it again) and between the XT crank and the steel frame and infrequent movement; it is always hard to move. So there are 3 data points to help your decision.

_________________
For certain parts stiffer is more important than lighter.