Q. Can I change the tyres of Renault Triber from 185/65 -15' to 195/65 - 15'? will it affect its mileage or pickup?

The upsizing you mentioned will result in 2.09% change in rolling diameter. Any rolling diameter change over 2% is not recommended because all that you see on your console (speed, distance, ABS, EBD etc) are electronically calculated based on rolling diameter. If the change is too far from factory settings no one can predict how the vehicle will behave. Anyway it is your vehicle you can do whatever you like at your own risk, as long as it doesn\'t break any law. If you go with 195/60/15 will result in -1.05% change, here you will lose a bit of ground clearance. The best configuration, in my opinion, is 195/55/16, where the change will be just -0.1%. (Just make sure the weight of the rims are almost the same so that you don\'t need to change the shock absorbers quite often).

Can i use 205 60 R 16 for replacing 185/65 R15