“Hey guys, How are you? I bought a new half-link chain for my BMX and the back sprocket keeps jumping teeth. Do I need a smaller, or larger rear sprocket? What should I do?”
Half link chains weren’t designed to work with 25/9 or smaller gearing. They will work in the short term but if you pedal a lot on new gearing, or have old, worn out gearing, you will notice it try climb out of the grooves between teeth on anything smaller then a 28/10. Your best bet is a DK Exo chain if you want a half link style chain or a full link 1/2x1/8” chain. I ride all over town between trail spots and riding street so I run a 30/11. It works with all chains and lasts twice as long when it comes to wear and tear.