I was riding with a SS the other night and his rear cog had spacers that acted like guards to keep his chain on . He did not know where these came form ( the builder added them ) but he loves loved them . Does anyone know what these maybe and where to find them?
Thanks ,
John

Is this really an issue? I've never had a chain jump of my cog when it wasn't an obvious chain tension issue.

Ive seen people who are rebuilding old thread on freewheels grind teeth off of high gears and use them as guides for single speed mountian or cross bikes. The set up went spacers-high gear-ridinging gear-high gears-spacers.