~The rear derailleur is controlled by the right hand shifter. It moves the chain between the smallest and the largest rear cogs on the freewheel (the gear cluster on the rear wheel). ~Check the following first: Make sure the bolt holding on the derailleur is tight. Use appropriate hex or allen wrench. Inspect pulley wheels on derailleur for wear, and insure that the chain is threaded thru properly. Check to visually see if where derailleur hangs from frame, it does not look bent on the hanger. Make sure the derailleur itself is not bent. ~You should make all adjustments on a bike stand, or with the bike up-side down. You should turn the pedals, and shift gears while you put it through it's paces. Keep in mind that the bike should be test ridden, as it may perform differently under load. Also, lube your chain before you start. ~Most problems of the rear derailleur are with the cable tension adjustments, and sometimes the limit screw adjustments. The cable tension can be adjusted at the barrell adjuster on the derailleur, or at the cable adjuster on the right hand shifter. To decrease cable tension, turn the barrell adjusters on the derailleur clockwise. Often, if your bike is making noise in gear, you may just need a simple cable tension adjustment done at the handlebar or rear derailleur. Try this first. Experiment by turning 1/2 - 1 turn, and then see if it helped. If not, go back and turn in the other direction and check it out. ~The limit screws are usually marked "H" and "L" for high and low. The "H" limit screw adjusts the outward movement of the derailleur to go on the smallest cog. The "L" limits the inward movement of the derailleur onto the largest cog. A good way to remember would be "same as a car". Low gear is for going uphill, and high gear is for going downhill. The "L" limit screw prevents the chain from coming off to the inside of the largest cog and hitting your spokes. The "H" limit screw prevents the chain from going off the outside of your small sprocket and hitting your frame. Tightening or loosening the limit screws only affect the inner and outer limit of movement of the derailleur, not the cable tension or alignment between gears... ~Here are the steps: 1) Adjust the "H" limit screw so that it shifts the chain to the smallest cog, but does not overshift. Tighten or loosen this screw until the derailleur shifts the chain to the smallest cog, but does not go past it. Adjust the limit screw, you may only need to turn it slightly. The cable tension should be slack at this point, and you could in fact have the cable disconnected to make this adjustment. 2) Adjust the cable tension so that as you shift up one gear, the chain moves to the next cog. Adjust this at the derailleur, and tighten or loosen the barrell adjuster as needed to get it to shift. If your cable was loose here, please cinch it now to tighten it to the derailleur. 3) Next, try to keep increasing the cable tension to get the chain to go to the largest cog by shifting your indexed or (grip shift) right hand shifter. 4) Set the "L" limit screw so that the chain goes onto the largest sprocket, but not to the inside of it. Try to line it up visually so the teeth line up in the middle of the largest cog and set the limit accordingly. Tighten the screw to keep it from going out too far. 5) Check your adjustments by alternately shifting back and forth from high to low gears, and seeing that it shifts smoothly, and does not go too far at each limit. 6) Adjust the cable tension as needed after taking the bike on a test ride. Major adjustments at the derailleur, and fine tune at the right hand shifter. Here, turning the barrell counterclockwise tightens the cable ( and thus makes it a little easier to get onto the next biggest cog.) 7) The final adjustment should be the "b" screw adjustment, which is the other little screw on the derailleur other than the low and the high screws. Adjusting this screw affects the distance between the upper jockey wheel on the derailleur, and the cog. Set this to allow adequate space for the chain to pass thru. Usually, you don't have to mess with this... Have any questions or comments, pleae call or e-mail us! |
