Originally Posted by
merlinextraligh
But my point is that its not a reasonable test of a set of brakes whether the bike stops downhill with just the rear brake, given that most of the braking force comes from the rear brake.
Out of curiosity, I tried this on my single bike, Dura Ace Calipers, Zipp pads (which are really Kool stops) dura ace aluminum rims. Brakes closely adjusted to the rims. At 20 mph using the rear brake alone, I couldn't skid the rear wheel even with a substantial amount of hand force.
Without the front brake shifting the weight forward, its not that easy to skid the rear.
I took what you said as being that it wouldn't lock up. Since you're saying that the bike wouldn't stop, by definition the brake wouldn't lock up. At the point the bike stops, the brake is locked. Thus if you could lock the brake, you'd skid to a stop.
But the broader point is that any bike is going to brake comparatively poorly with the rear brake alone. The relevant question is how the bike brakes using both brakes.
I won't argue that most of the braking force is from the front brake. However - my options in front were limited to either V-brake or caliper at the time - since no front discs were available. I wanted to see which rear brake was the most powerful and when it came down to it - the disc proved that it was more powerful than either of the other two. Both the Vbrake and caliper brake in front were similar but since they had different brake pad compounds it was hard to say which was better. In fact - the same held true for them in the rear.