Hi all. I'm working with my kid on a project bike and we've overcome lots of obstacles on this project, and I'm super thankful for the help here with the prior question you helped us with.
I just noticed something a bit odd. See the blue bike frame photo. By the crank and bearing there's some threading, but no flat spinny piece that goes on the threads. Do I need that piece and what is it called? I looked around the web and can't find it. Also is it just one size fits all or do I need a specific specification to get the right one?
In the other photos are our family's other bikes that do have that flat piece that I'm asking about.
Thank you!
by Hows-It-Goin-Buddy
3 Comments
That is a lock ring. You need it if the bottom bracket on the bike is a “cup and cone” style, but if it’s a “cartridge” style, you don’t.
I believe the piece you’re asking about is a bottom bracket locking ring. It’s needed for non cartridge bottom brackets that have an axle and two cups either side. I can’t quite tell from the photos but the first photo looks like a cartridge BB which wouldn’t need it. What does the other side look like?
It’s called a bottom bracket lockring. You need it for cup & cone, non-cartridge, square-taper bottom brackets. If you have a cartridge bottom bracket, you don’t need it.
Cup & cone is more common on vintage bikes; more contemporary frames typically use a cartridge. This is cup & cone with lockring:
https://preview.redd.it/lz6stcuj7nnf1.jpeg?width=362&format=pjpg&auto=webp&s=6088a09335fdd5105f2c3a6417571ce41c2c6c59