Uploaded December 2021 | Updated September 2026, 19 hours ago
I recently upgraded one of my bikes with an American-to-European bottom bracket adapter because I was tired of the one-piece crank bearings failing. This came with a whole host of surprises, namely the adapter not fitting without some rather involved modifications (article on that here: greensandmachines.com/2021/09/american-to-european-bottom-bracket.html ). I also had to machine a spacer washer to get the bottom bracket to fit properly. After riding with it for a couple months, the bottom bracket started coming loose. I tried retightening it a few times, but I noticed the real problem was the lock ring, which was plastic, had cracked. Incidentally, this was a second hand bottom bracket, presumably unused, which came in a bag with a note saying Shimano had recalled it (I wonder why). Not wanting to go through the trouble of trying to order replacement parts, I set out to machine my own metal lock ring. It sounded like a good challenge to machine something with this degree of complexity. Plus, who doesn't like how a good spline pattern turns out?
A note of how the new one performs: I may have done a poor job machining the small internal taper in the bore which supports the end of the bottom bracket cartridge, it was a very difficult feature to measure and may be over size. The new lock ring came loose after a few weeks the first time I installed it. I have since reinstalled it with some thread locking compound and it seems to be holding up without issue.
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Credits to DJ Petesake for the music in this video. Visit his Soundcloud to download the soundtrack:
soundcloud.com/djpetesake/sets/greens-and-machines-soundtrack
Visit greensandmachines.com for more
I recently upgraded one of my bikes with an American-to-European bottom bracket adapter because I was tired of the one-piece crank bearings failing. This came with a whole host of surprises, namely the adapter not fitting without some rather involved modifications (article on that here: greensandmachines.com/2021/09/american-to-european-bottom-bracket.html ). I also had to machine a spacer washer to get the bottom bracket to fit properly. After riding with it for a couple months, the bottom bracket started coming loose. I tried retightening it a few times, but I noticed the real problem was the lock ring, which was plastic, had cracked. Incidentally, this was a second hand bottom bracket, presumably unused, which came in a bag with a note saying Shimano had recalled it (I wonder why). Not wanting to go through the trouble of trying to order replacement parts, I set out to machine my own metal lock ring. It sounded like a good challenge to machine something with this degree of complexity. Plus, who doesn't like how a good spline pattern turns out?
A note of how the new one performs: I may have done a poor job machining the small internal taper in the bore which supports the end of the bottom bracket cartridge, it was a very difficult feature to measure and may be over size. The new lock ring came loose after a few weeks the first time I installed it. I have since reinstalled it with some thread locking compound and it seems to be holding up without issue.
Subscribe to Greens and Machines for more Gardening, Homebrewing, Machining, and other DIY videos.
Credits to DJ Petesake for the music in this video. Visit his Soundcloud to download the soundtrack:
soundcloud.com/djpetesake/sets/greens-and-machines-soundtrack
Visit greensandmachines.com for more
