On 12/16/06, hersefan@comcast.net <hersefan@comcast.net> wrote:
>
> This one is curious - was it the crown that failed, the blades that bent,
> or the wheel that hit the downtube?
>
> Many bikes, even heavy duty touring bikes, have used round blades with no
> ill effects. It all depends on the weight of the blade of course. Was the
> forkcrown weakened by the drilling perhaps? Alternatively, is it certain
> that the frame was never crashed - otherwise perhaps the tube or crown was
> compromised already and the braking led to a failure. Seems like it would
> be good to understand this one as in most instances use of a track blade (of
> sufficient gauge) with drilled crown is uneventful and even a choice of some
> builders.
>
> Mike Kone in Boulder CO
Isn't it a consensus view that the actual deflection apparent while braking- and hence presumably the attendant stresses- actually take place above the fork blades? If this is in fact the case, I'd expect whether the fork blade sections are round or oval to be essentially immaterial to braking.
Kurt Sperry
Bellingham WA
USA