i don't know man... probably because it's a lot easier to adjust them, plus brake shoes last two times longer than on mechanical brakes. When you press a brake lever, two pistons squeeze the rotor instead of one keeping the rotor straight all the time. just be careful when you decide to bleed your brake, because brake fluid is pretty dangerous (it will damage paint on the bike and take off the clear coat of the wood if you spill it on the floor) and make sure you have clear glasses and latex gloves on while you bleeding the brake. I have avid elixir 3 on the front and juicy 3 on the rear (elixir works a lot better but cost a little more)