Front derailleurs are attached to the bike with either a clamp or bracket. You need the correct "clamp size" the clamp is the ring that anchors the derailleur to the bottom of your seat tube. The crankset is the cluster of chains and gears attached the the pedal. The cable will come loose from a slot underneath the derailleur. Remove the chain from the derailleur with a Phillips 6mm screwdriver.
Some chains have a special connector pin that will need replacing if the chain is removed. Rest the chain on the bottom bracket shell to keep it out of the way. Before removing the clamp post, mark where it is positioned with a felt tip or Expo marker. This ensures the new part will be placed in the same position. Unscrew the 5mm hex bolt that tightens the clamp onto the seat post.
Before installing the new derailleur, apply some WD to the mounting bolt. Place the clamp around the frame and tighten the mounting bolt just enough to keep it in place. At this point you still need to be able to move it by hand. Check to make sure the cage of the derailleur will clear the large chain-ring when the the hinge extends. Take up the slack on the shifter cable with pliers and tighten down the bolt on the retaining clamp.
Thread the shift cable back into the derailleur, pull it tight and tighten the anchor bolt so the cable flattens. Then find a bare stretch of cable and give it a good pull to make sure the cable is seated and has no slack. Then loosen the cable, pull it tight again and re-tighten it. If your chain is still on the bike, undo the tail screw on the derailleur cage and flex the cage to pull the chain through.
Then re-install and tighten the tail screw again. If you have removed the chain, re-route the chain through the derailleur cage and reconnect it.
While changing gears if you have to force them to change, the derailleur was put on incorrectly. The casing for your cables can break. Run through the entire range of rear sprockets to make sure the chain does not rub on either side of the front derailleur cage. Turn the bike to standing position. Use half turns while adjusting. For height adjustment, the bottom edge of the outside derailleur cage should sit approximately 2mm above the top of the teeth on the largest chain-ring.
For the angle adjustment, rotate the derailleur until the cage is parallel with your chain-rings. Adjust the derailleur limiting screws and cable tightness as needed. Maintenance includes: Changing through the gears one or two at a time.
Making the chain ride up and engage with another cog is a combination of your smooth pedalling action and a crisp clean shift. Sometimes you need to press your lever or twist your wrist just that little bit more before you release it. Aim for a good firm shift rather than a cautious hesitant one. With derailleur gears, you cannot change gear when you are stationery and changing out of the wrong gear whilst you are going slowly or pedalling up a hill for example can be very difficult.
You need to be in the right gear for the moment. Front derailleurs may cause sluggish or inaccurate shifting because A the derailleur body is not positioned properly, B the derailleur limit screws are not adjusted correctly, C the mechanism is dirty or D the cable is damaged or improperly tensioned. Can I use a 9-speed derailleur on a 7-speed cassette? Shimano 7-speed derailleurs have a rear shift ratio of 1. Therefore, a 9-speed derailleur should work fine with a 7-speed cassette if the shifter and the cassette match the brand of the derailleur.
You need to pull it pretty tight before clamping it to the derailleur. Probably as tight as you can. That said, derailleur springs will lose tension overtime, and pivots will get sloppier. Derailleurs will last almost indefinitely. If a bike veers to one side when ridden no-hands, it can be corrected by bending the forks to the same side as you must lean to ride straight. This is done by bending the fork blades one at a time, about 3 mm.
The problem is usually in the forks although it is possible for frame misalignment to cause this effect. Adjust to the correct height The front derailleur should run parallel to the chainrings. When directly above the large chainring, the outer edge of the derailleur should sit mm above the teeth of the chainring. It is generally a good idea to lubricate the pivot point of the front derailleur with a light lubricant.
The cable inner wires should also be lubricated. If you have loosen the inner wire pinch bolt, lubricate those threads as well.
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