Park Tool FAG-2 Frame Alignment Guage

Bike doesn't shift or track properly after a derailleur and wheel adjustments?

Then the FAG-2 frame alignment tool is what will isolate the issue. Using the string method to check alignment is inherently flawed as it does not take the measurement at the dropout. The FAG-2 alignment tool can check the alignment quickly and accurately at the dropout, eliminating a lot of time and frustration for the Mechanic.