If you have to perform repairs on your own Derbi GPR 50 R then it is always a good idea to have access to a Workshop Manual to use as reference in case you want to know techniques to take out a particular component for instance the Wheel and match it again accurately.
Derbi GPR 50 R Workshop Manuals offer you special diagnostic wisdom on your car so if something is faulty it will help you discover what the situation is and the best way to fix it. Then you are able to analyse if you can do this yourself or if the job is simply too big you can still book your GPR 50 R in with a trusted friendly mechanic.
Derbi GPR 50 R manual