You also have to consider that depending on your position on the bike, you don't always have the leverage available to pull the brake levers as hard as you can at other times. There's one particularly steep hill with a stop sign at the bottom here in town. If the riders on race bikes lean all the way down to really get a good grip on those levers, they'll go a** over tea kettle. Most of them brake from their towers which takes away most of the leverage and prevents them from stopping short. When I'm on my cross bike with its cantis set up real strong, I have no problem stopping short.