Park Tool Derailleur Hanger Alignment Gauge - Manual

Park Tool Co. 5115 Hadley Ave. N., St. Paul, MN 55128 (USA) www.parktool.com
DAG-2 Derailleur Hanger
Alignment Gauge
Proper alignment of a bike’s derailleur hanger is important for reliable shifting. While a derailleur hanger can be
bent when a bike is crashed or dropped on its side, even new frames often have misaligned hangers. The Park Tool
DAG-2 provides a simple, accurate means for checking hanger alignment and for straightening hangers that are not
properly aligned
ASSEMBLY
Install indicator (Ref #4) into sliding bracket
(Ref #7) and tighten knob (Ref #1). Install one
o-ring at each end of indicator. The o-rings
will serve to retain indicator in the DAG-2.
INSTRUCTIONS
1. Install wheel in frame. Make sure rim
is correctly centered in frame.
2. Remove derailleur from derailleur
hanger.
3. Thread inside shaft (Ref #3) into derail-
leur mounting hole.
4. Loosen knob and move sliding bracket
and indicator so tip of indicator contacts outside
edge of rim (position A). Tighten knob.
5. Move sliding bracket so indicator is clear of rim.
Then rotate tool 180 degrees to position C.
6. Move sliding bracket and indicator to outside edge
of rim. If tip of indicator is within 4mm of outside
edge of rim, the hanger is aligned horizontally. If tip
of indicator is 4mm or more away from rim, or if indica-
tor presses against rim, the hanger is misaligned. Move
sliding bracket and indicator so they are clear of rim. Then
use weldment (Ref #6) as a lever to bend hanger into
alignment horizontally. Repeat checking and bending be-
tween positions A and C until clearance is less than 4mm.
7. After achieving correct horizontal alignment, keep indica-
tor in same position and rotate to position B. If clearance
between outer edge of rim and tip of indicator is less than
4mm, rotate tool to position D. If clearance is greater than 4mm,
or if indicator presses against rim at position B or D, use weld-
ment as a lever to align hanger vertically.
8. With properly aligned hanger, tip of indicator should just contact
outer edge of rim at one position and have no more than 4mm
clearance at any of the other positions. Check and align all four
positions until this is accomplished.
Notes
The two o-rings on the gauge bar may be used as markers when using the DAG-2 on a bike with interference from
a rack or other accessory. After moving indicator to rim and tightening knob, move outer o-ring against sliding
bracket. When it’s necessary to clear a rack or other accessory, simply loosen knob, pull indicator back to clear rack
or other accessory, push indicator in until o-ring contacts sliding bracket in original position, and tighten knob.
Always take
readings with
indicator at
valve hole to
insure wheel
trueness will not impact accuracy of tool.
Also, always take readings at outside edge of
rim to minimize errors that may be caused by
rim’s sidewall slope.
C
B
A
D