I've got a Surly CC set up with single 38chainring and 11-28 8spd with bar end shifter. The problem I've been having is the chain getting jammed outside the 11t. cog when tossed down multiple cogs (friction mode) as though the set screw adjustment was too loose AND the derailleur not shifting from 13t-11t cog as though the adjustment screw was too tight or the friction in the cable wire too high.
It's a little confusing but maybe the latter problem is the case. Curious if anyone else has troubleshooting suggestions. It shifts perfectly fine and quiet through the gears. It makes sense for it to not shift well to the 11t. cog if the set screw was too close but being able to jump across doesn't sound right.
Maybe the angle of the cage is critical? Chainlength/wrap is ok.