We have two bikes and both of them will not change gear, on one when you try to change grear with the grip the derailleur wont move at all, and the second bike is the same but that will move a little bit.
both cables are free. please can any one help as we need these bikes for a fun raising event in two weeks thank you for your help in this matter. John

john, August 2010

Dear John. Is it possible that the HIGHER AND LOWER deraillieur screws at the rear deraillieur are not in their right positions. if you have replaced cables and not set the screws for adjustment to suit the deraillieur then this might be your cause for problem. I have found that if cables are replaced then sometimes the screws need to be readjusted to suit the gear ratio. I have put WD40 into cable sheaths instead of normal oil but if you haven't got WD40 use old engine oil /grease it reduces rust too. Check your deraillieurs from top to bottom it is possible that something is broken (teeth on small wheels) on deraillieur

Anthony Tovey, September 2010