Hello. i just bought a monty 20" bike (custom built). I have noticed a few problems with the front hydraulic disc and the rear brake is insainly squeeky and has the rear rim is very rough, had to be done on purpose, somone told me it was for extra braking power but i dont like the noise it makes when i apply the brake. is there any way to fix the rear rim like by sanding it or somthing? my front brake is lacking sharpness and i dont know how to check the pads incase they are worn or somthing. (this is my first trials bike lol) please help me! My mate has a onza rip and his front v-brake is sharper than my hydraulic disc.