Originally Posted by
Andy_K
I hate to be the one to go all geek but...
I know it's counter-intuitive, but the surface area of the brake pad actually doesn't matter. As you increase the surface area, it distributes the normal force (the pressure of the pad against the rim) and so twice as much surface area leads to half as much force at any given point. This exactly counteracts the increased drag of the larger surface area.
Actually, I appreciate you going all geeky and clarifying that.
Thanks. That make sense now that I think of it.
Plus you have rationalized my decision to stick with road size kool stop pads rather than cramming the big silly mountain bike sized ones on there.
Still, I wonder if there is some practical limit. For example would a pad 1/4 the normal area have the same drag? Perhaps increased pressure would mean increased temperature and change the friction of the pad? Or perhaps it would have the same braking power and it is just a matter of pad wear?
Corrected?
brake stopping power = [(pad friction) x (mechanical advantage)] - (cable flex + arm flex)