If one part is not working well or is worn , it will affect the whole bike. It is common to find that when you think only one part needs repairing/replacing that faulty part may have affected other parts and just to replace one part ( eg. the “slipping chain” ) will not always fix the problem. Let us do a proper repair and don’t ask us only to do the minimum by only doing a part repair. You will not be satisfied with the outcome. Please remember we love your bike and do not want to do a rush job on it , so make sure there is plenty of time for us to repair your stead before a big race or tour.