Originally Posted by
DannoXYZ
He's got the opposite problem with the cable being too tight and off by one click. The shifter-position for the smallest cog ends up dropping into the 2nd cog. He needs to unbolt the RD cable and loosen up about 3mm of cable. Depending upon the position of the barrel-adjuster, he might be able to spin it in enough to loosen up the cable enough to drop the RD into the 1st cog.
"The cable is plenty slack in the low"
I think he means the cable is slack in the high gear, which would indicate either the high limit screw needs to be adjusted or the derailer hanger is bent.