I believe that the need for larger brakes is based on the larger diameter of the tires more than the weight. You're dealing with more torque (at the same road speed) applied by the road under braking (as long as you have traction) with larger diameter tires. Having said that, the handling decrease you get with really large tires will usually moderate your speed. I believe the stock brakes in good condition will take care of anything you need them to, unless you're racing........

Randy