Quote from: mbt on September 03, 2021, 10:57:30 PMQuote from: mbt on September 03, 2021, 03:04:09 PM
The chain is skipping the rear cog on my brand new Radrunner as well. Happens under moderate to strong pedaling forces. My wife managed to get a video where one of the video frames clearly shows the chain lifting off the rear cog teeth and skipping over the the next valley. The chain tensioner is not bent and is properly aligned to the plane of the chain. Rather disappointing to have this happen on a new bicycle. Its not like chain drive is a new thing and people are still figuring it out.
Anyhow, my feeling that issue is a combination of insufficient chain wrap around the rear cog and too light of chain tension. Its easy enough to increase the tension by removing a chain link pair, but there is a finger on the chain tensioner mounting tab that prevents the amount of wrap being further increased past the current amount. I'm still waiting to hear back from RPB on what they suggest doing. With that said, I'm curious if anyone having this issue with a Radrunner or other single speed RPB have resolved this issue.
So, I almost fully resolved the issue by grinding tab on the chain tensioner mounting flange to increase the amount of chain wrap and by removing a link pair. Its not 100% fixed, but its pretty close. It skipped only once or twice under very heavy load. I'll probably grind the tab a little more to further maximize the amount of wrap.
I've decided that the root of the issue is the chain tensioner. The tensioner pulleys should be much closer to the rear sprocket. This would help greatly in keeping the rear chain pushed up against the sprocket.
Thanks for your story! I've never seen a chain tensioner/derailleur designed to be so far away from it's intended target. I may just replace the tensioner with an old derailleur.
