SO are you trying to change to a different braking system or are you just wanting to change the brake pads? If you are trying to change to a different braking system like say disc brakes your frame/fork and wheelset would have to be compatible. If your looking to change the pads (which can give you much better stopping power if you get good pads) that is fairly simple and easy enough. People on this forum swear by koolstop salmon pads claiming that they brake much better than other stock or cheapy pads. Give a little more detail about what your trying to accomplish.