My chain does not seem to be shifting smoothly. Changing down (to a bigger sprocket) is no problem. There are two spockets (my favourites) that when changing down the chain doesn't quite seem to make it into place. Makes a bit of a rough skipping sound. I can get over it by changing up an extra gear and then changing back down but this is a bit of a pain.
Does anyone know whether the cluster might be had it or any other issues that might be to blame. I've done 7000km on the bike since new and the chain was changed at about 6000.
Quite possibly its because the cables on your derailure are too taught and won't allow the derailure to move enough to switch the chain which is why it works to shift up two then down one. A sign this is happening is when you are peddaling you can hear the chai rub against the derailure and have to adjust the shifter slightly to get the sound to stop. Also, the spacing between your gear plates may have been changed somehow. If the rings are bent or there is a larger than norml gap between plates sometimes its harder for the chain to switch. If this is the case, simply get off the bike and pedal slowly with your hand to see if you can detect any wavering in the gear teeth. Most plates can be bent slightly without doing much structural damage to it. Be careful with it and good luck.
