Cyclus Tools straightening tool for derailleur hanger

Check and correct with this device the exact geometric position of the Schaltauges at the dropout. Mount a rear wheel in the frame and remove the rear derailleur if necessary. Disassemble the nut from the threaded spindle of the Lehr, screw the tool into the derailleur hanger as far as it will go and counter it with the nut. Now check the uniform distance to the rim (measuring pin) at several points of the wheel circumference. If differences are found, the derailleur hanger must be adjusted accordingly.