I had something like this and it turned out to be this master link in the chain. I noticed it happened once for every 2 rotations of the cranks, then i noticed that the master link in the chain came round once every 2 rotations of the cranks.
It was a stiff link
@rabsda started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
I had something like this and it turned out to be this master link in the chain. I noticed it happened once for every 2 rotations of the cranks, then i noticed that the master link in the chain came round once every 2 rotations of the cranks.
It was a stiff link