Joined: Feb 2012
Posts: 19,344
Likes: 5,460
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Make sure the chain is fully seating in the cog valleys. Sometimes the wrong spacers or lockring will keep the chain from engaging the teeth to a full depth.
Tight links, twisted links, connector link/pin not fully set.
The smaller the cog the more the need to have all right.
Try another chain.
Why are you climbing in such a high gear any way, and maybe in a crossover one at that? Andy.