Review on Park Tool DAG 2 2 Derailleur Alignment by Keith Aluguvelli

Although Leonard Zinn (bike maintenance guru) classifies repairing derailleur hangers as a Level 3 task (for advanced DIYers or DIYers). mechanics), it's actually a very simple job. You unbolt the rear derailleur, screw in a DAG 2.2 stud, and then spin the tool and check that the odometer (rod) stays constant around the wheel. If this is not the case, apply a lever to a steel rod and bend the switch bracket in the appropriate direction until it is correct on the horizontal and vertical axes. Of course, this works best with a steel frame due to its ductility, or simply with a slightly curved aluminum temple. If you have a severely bent aluminum hanger, it may be better to buy replacements as they typically cost $10 or less for your particular frame. (A machine shop can also custom make it for about $30 if your frame builder goes out of business). If your derailleur hanger is made of titanium, you will need to have the bike checked by a reputable shop that has experience with frame alignment issues, as titanium does not have the ductility of steel or aluminum. (Most respected titanium frame manufacturers use aluminum temples as the industry standard after about 2002). I do bike repairs in my area and probably twice a year a kid brings their bike back from an accident with a bent derailleur hanger. I replaced my old derailleur alignment tool with this model DAG 2.2 Park Tool and so far it has made every job a breeze. This tool is well made from hard tool steel (Rockwell hardness around 61 I believe) and meets the standards of a professional mechanic. I've had five stars so far and this is one of the best tools the Park Tool line has.