Learning how to adjust the Shimano 105 front derailleur will keep the bicycle chain from falling off the chain rings as the gears shift as well as prevent the chain from rubbing. The basic adjustments on the front derailleur include the height and angle, limit screws, and adjustment of the cable tension. Adjusting the Shimano 105 front derailleur will lead to a much safer and enjoyable ride.
To adjust a Shimano 105 front derailleur, you will need:
- 5mm Allen Key
- Small Phillips Screwdriver
- Adjust the height and angle of the Shimano 105 front derailleur by positioning the clamp that attaches the derailleur to the bike frame. Clamp should be secure but loose enough to move up and down with your hand.
- To get the correct height, the front derailleur case should be close to the large sprocket teeth with a 2mm spacing between them. The lower the cage the better for shifting. Use the 5mm allen key to make the adjustment.
- Adjust the low-gear Phillips-head limit screw but first make sure the chain moves to the largest sprocket on the rear and the smallest sprocket at the front. Place the inner plate so that it just clears the chain in the lowest gear. If it is too loose, the chain will drop off when downshifting the small chain ring. If it is too tight, it will not shift down at all.
- Adjust the high-gear Phillips-head limit screw, but first shift into high-gear so that the small sprocket is in the rear and the large sprocket is in the front. Adjust until the cage stops just after it clears the chain on the large chain ring.
- After both limit screws are set, move the large sprocket in the rear and the small sprocket in front. The front derailleur shifter should be in the lowest gear position. Pull the shift cable to remove any extra slack before tightening the cable bolt using the 5mm Allen key.
- Shift the Shimano 105 front derailleur to middle gear running through the whole range of rear sprockets. If the chain rubs on either side of the front derailleur adjust the trim by tightening or loosening the barrel adjuster on the front shift lever.
Before taking the bike out on the road make sure to fine tune any adjustments needed on the Shimano 105 front deraileur.