gears

Introduction
Gears are part of your drive chain, and for your gears to work you must ensure all the parts in the drive chain are working.

1. Aligning your rear mech.

a. View the rear mech and cassette cluster from behind as shown. With all your cables unattached the jockey wheels should line up vertically with the largest and smallest sprockets when pushed to the extremes of its movement. If it doesn't you will need to adjust the 'throw' of the mech using the two small screws positioned on the back of the mech.

b. The screw to adjust the mech at the largest sprocket will usually be marked 'L' for low, and the screw for the smallest sprocket adjustment marked 'H' for high.
NB: the spring in the rear mech is at its weakest when trying to pull the chain down onto the smallest sprocket, (except in some new Shimano mechs where this occurs on the largest sprocket), in some cases you may have to 'over-adjust' the mech at this point, giving it more room to throw the chain over.

2. Aligning your front mech.

This works in much the same way as the rear mech, with two screws to adjust it's throw. But to line the front mech up you'll need to have the chain fitted.

a. With the chain on the smallest sprocket and largest chainring (highest gear) adjust the front mech so that it just clears the chain on the outside of the largest chainring.

b. With the chain on the largest sprocket and smallest chainring (lowest gear), adjust the front mech so that it just clears the chain on the inside of the smallest chainring.

c. If you have an indexed front shifter you'll need to pray it has a barrel adjuster on it or it can be a bit of a pain to set up.

3. Attach your cables

If your cables are not already attached, do this now. Using a pair of pliers pull the cable through the clamps on your front and rear mechs and tighten with the correct tool, usually a 5mm hex key or an 8mm spanner. Ensure you have pulled any slack through and that the cable is not snagged anywhere along its route.

4. Rear Mech and Right Hand Shifter.

a. Shift into the largest chainring and smallest sprocket (highest gear). If the chain is hesitating when trying to drop onto the smallest sprocket, first try loosening the cable a little, either by turning the barrel adjuster on the mech or shifter clockwise, or loosening the cable clamp on the mech a little and feeding some cable through. If you still have no luck try turning the throw adjustment screw anti clockwise half a turn, and re-trying the above.(If you find the chain is being over shifted into the frame, or off the sprocket, turn the throw adjustment screw clockwise to correct. Re-clamp the cable and start again.)

b. Click one shift up on your right hand shifter whilst turning the crank. If it doesn't shift up immediately turn the barrel adjuster on your mech or shifter anti clockwise until it does. If you find it is over shifting turn the barrel adjuster clockwise until it runs smoothly in the correct gear.

c. Repeat b. until you have covered 2 or 3 of the rear sprockets. Your rear mech should then be indexed to your shifter.

d. Commonly ignored, the 'b' screw on the rear of the mech can improve shift speeds no end. Adjusting this screw changes the distance between the points where the chain leaves the jockey wheel and makes contact with the sprocket teeth. This distance is ideally two chain links, so play around with the screw until you get as close as you can to this ideal.

5. Front Mech and Left Hand Shifter.

a. With your chain on the smallest chainring and a middle sprocket, click up one shift on your left hand shifter, if the chain has not shifted to the middle ring after one rotation of the crank, adjust the barrel adjuster on the shifter anti clockwise until it shifts smoothly and cleanly upwards. If, at the extreme of the barrel adjustment, it is still not shifting you may need to pull some more cable through the clamp. This is aided by screwing in the bottom throw adjust screw by one turn, pulling the cable through, then loosening off the screw by one turn again. Remember you have already carefully set the swing of the front mech so don't ruin it by forgetting to put the screw back to the same position.

b. Once in the middle ring it is worth checking that your chain is not rubbing on the front mech whichever sprocket you are in. Do this by shifting into the middle chainring, then sweeping between the rear gears. If they are rubbing at either side, adjust using the barrel adjuster on the shift lever.

c. Shift up into the largest chainring, check you have no rubbing, adjust if necessary as above. If you find the chain is thrown off between the chainring and the crank, turn the top throw adjustment screw clockwise half a turn at a time until the problem ceases.