Useful Tools and Supplies

• Repair Stand, holds bike secure for easy work.
• Hex wrenches as needed.
• Screwdriver (#2 Phillips or straight blade)
• Light liquid lubricant
• Derailleur cable inner wire and housing as needed
• Caliper or metric ruler
• Cable end caps and housing end caps as needed
• Rags

• Rear derailleur- limit screws and index settings
• Wire cable-sizing and cutting inner wire cable and housing (gear and brake)
• Brake and Shift levers
• Rear derailleur- overhaul
• Rear derailleur- bent hanger

Service Procedures

Front Derailleur Height

1. Inspect height alignment of front derailleur. The outer cage plate must be positioned over the largest chainring when viewing height. Simply grab the exposed front derailleur inner wire until outer cage plate is directly over outer chainring teeth. Use care to not shift the derailleur cage past this point. Note height and direction of change needed. It is then necessary to relax the cable to loosen the mounting bolt and raise or lower the height as needed.
2. The gap between the teeth of the outer chainring and lower edge of the outer cage plate should be 1-2mm, about the thickness of a penny. Using a penny or a dime as a feeler gauge, fit it between the chainring teeth and the cage plate. It should just fit between the teeth and plate. 
3. To lower cage, release inner wire tension completely by shifting to innermost chainring. Note angle of outer cage plate relative to chainring.
4. Front derailleur clamps typically leave a mark on the frame, which is useful as a reference when changing height. Loosen derailleur clamp bolt, change derailleur height, and return cage to same rotation relative to chainring. Tighten clamp bolt. Move outer cage plate over outer chainring, and check height again. Repeat this process until cage plate height is 1-2mm above outer chainring.

Front Derailleur Rotational Angle

1. Shift chain to outermost chainring and outermost rear sprocket.
2. Sight chain from directly above chainrings. Consider the chain as representing a straight line. Compare this line to outer derailleur cage plate. Outer cage plate and chain should be parallel. Keeping the cage and chain parallel will minimize the risk of the chain jumping off the outermost ring. If cage is not parallel, there will be a relatively large gap at either the back or the front end of the cage, and the chain may over shift.
3. If derailleur cage needs to be rotated, note direction of desired rotation.
4. Release inner wire tension by shifting to the innermost chainring.
5. Many clamps leave a slight marking on the frame. Use this scarring as a reference when changing height. It is also possible to use a pencil to make two reference marks on the frame, one for height and a second, vertical mark, to reference rotation. Use the marks to avoid inadvertently changing height.
6. Loosen clamp bolt and slightly rotate in correct direction. Use care not to change height. Tighten derailleur clamp bolt.
7. Shift to outer chainring and observe rotation alignment. Repeat adjustment if necessary.

Front Derailleur Limit Screw Settings

Front Derailleur - Adjusting L-screw

1. Shift chain to innermost rear sprocket and innermost front chainring. Inspect derailleur for marking indicating "L" screw.
2. Check inner wire tension. It should be fairly loose at this time. If inner wire is taut, turn barrel adjuster clockwise into housing. The barrel adjuster is typically located where the cable housing enters the shift lever. If barrel adjuster is already fully turned into housing, loosen inner wire pinch bolt, slacken inner wire and retighten bolt.
3. Sight gap between inner chain plate and inner cage plate. Only a small gap should be visible, about 1/16" or 1mm, about the thickness of a dime.
   
4. Pedal bike slowly and continue to sight gap. Set clearance at tightest point in chainring rotation. Adjust L-screw so there is a small gap between inner cage and inner chain plate. Pedal bike and check that chain is not rubbing cage as chainrings turn.

    1. If there is no gap and chain is rubbing cage, loosen L-limit screw 1/8 turn (counter-clockwise). Inspect for gap again and repeat until slight gap appears. 2. If the gap appears larger than 1mm at its widest point, tighten the L-screw, in small increments, until the gap closes.

5. Test the shift by shifting chain to next chainring then shift back to the innermost ring. Do not use the shift lever. Pull on the inner wire to shift the derailleur. Using the lever may confuse limit screw issues with cable tension issues. If chain shifts quickly, limit screw setting is adequate.
6. If the shifting appears is slow (requires more than one pedal revolution to initiate shift), turn L-limit counter-clockwise 1/8 turn and repeat test. Repeat 1/8-turn increments until shifting is adequate. The gap will open wider than the 1mm target, but will still be as small as possible with adequate shifting.
7. If chain is shifting beyond the inner ring and falls off the chainring, gap may be too large or cage alignment may be off. Tighten L-screw 1/8 turn and check shift again. If chain ends up rubbing inner cage of derailleur, yet still drops off inner ring when shifting, other problems such as chain line or derailleur rotation exist.

Front Derailleur- Adjusting H-screw

1. Shift to outermost sprocket in rear and outermost front chainring. Inspect derailleur for mark indicating H-screw.
2. Pull inner wire with hand to increase tension to insure derailleur is against H-screw.
3. Maintain full pressure on inner wire and check gap between chain and outer cage plate. Only a small gap should be visible, about 1/16" or 1mm. Pedal bike slowly and continue to sight gap. Set clearance at tightest point in chainring rotation.

    A. If chain is rubbing cage, loosen H-screw 1/8 turn and pull fully on inner wire. Check gap again. B. If chain is not rubbing, tighten H-screw repeatedly until chain is 1mm

4. Test shift to the large ring. Shift derailleur from next to largest to largest ring using hand pressure on inner wire rather than shift lever. If shifting is slow, loosen H-limit screw slightly and repeat test. If chain shifts off the outside of the large chainring, the outer-limit is set too loose. Tighten H-screw limit and test shift again.

Front Derailleur- Adjusting Indexing (Three Chainring Bikes)

1. Shift chain to middle chainring in the front and innermost rear sprocket.
2. View gap between inner cage plate and chain. Gap should be as small as possible without rubbing chain.
   
3. To reduce gap, increase inner wire tension by turning barrel adjuster counter-clockwise. Adjusting barrel may be on frame or on shift lever. Check gap again.
4. If chain is rubbing cage, turn barrel adjuster clockwise, or inward toward shifter body.
5. If barrel adjuster is all the way in or out there will be no adjustment possible. In these cases reset the barrel.   Shift to innermost chainring and loosen inner wire pinch bolt. Turn the barrel fully clockwise and back out about 2 full turns. Pull wire gently with fourth-hand tool and tighten pinch bolt. Begin adjustment of inner wire tension as above.
   
6. Test shift of front derailleur to all three front chain rings. If the derailleur rubs in the largest front chainring, double check H-limit screw and inner wire tension, which may be too loose. If chain is slow to shift to smallest chainring, double check L-limit screw and inner wire tension, which may be too tight.

Front Derailleur- Adjusting Indexing (Two Chainring Bikes)

1. Shift chain to outer chain ring in the front and outermost rear cog.
2. View gap between outer cage plate and chain.
3. If outer cage plate clears chain, index setting is adequate.
4. If plate is rubbing chain, increase inner wire tension by turning adjusting barrel counter-clockwise and check again.
5. If barrel adjuster is all the way in or out there will be no adjustment possible. In these cases reset the barrel.   Shift to innermost chainring and loosen inner wire pinch bolt. Turn the barrel fully clockwise and back out about 2 full turns. Pull wire gently with fourth-hand tool and tighten pinch bolt. Begin adjustment of inner wire tension as above.
6. Test shift of front derailleur to both front chainrings.

Front Derailleur Performance