Michael Press wrote:

I experienced something a bit unnerving yesterday on a
bike I have been riding a couple years. The bike is a
nifty steel sport frame. The brakes are Ultegra 49 mm
reach with Kool Stop pads. On descents I was waiting a
bit longer before braking at turns, using more braking
force, but still using progressive force, rather than
slamming them. At a later point in the brake
application, the braking force suddenly increased
sharply. This happened more than once. Had not seen
this before, and need more experiments. Any comments on
this sketchy account?

Something sounds very wrong here... Perhaps you've got the pads toed
out (with a wider gap at the leading edge of the pad than the trailing
edge). That can cause this kind of thing (though normally it'll still
be somewhat progressive in nature).

Maybe it's just contamination on the rim or brake pad? A bit of
water? If you go into a corner on the brakes hard with a wet rim, the
braking WILL "improve" sharply when the water is removed by the first
couple revolutions of the wheel (give or take).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame