My rear mech does move inwards when tightening the skewer but then the gears are tuned afterwards. There should be no reason in your setup that this would prevent you hitting the 11/12 cog.
More likely your limit screw is causing the issue.
My rear mech does move inwards when tightening the skewer but then the gears are tuned afterwards. There should be no reason in your setup that this would prevent you hitting the 11/12 cog.
More likely your limit screw is causing the issue.