[QUOTE=rhm;15094802]When frames fail, for whatever reason, they tend to fail either at, or very near to, the points where the tubes are joined together. To overcome this tendency, builders make the joints stronger, and the ends of the tubing stronger, so they don't fail. If the builder reinforces part of a tube, there will be a point of transition from the stronger part to the weaker part; that point of transition then becomes the weak point, and therefore the point at which the tube is most likely to bend. Thinned lugs and lugs with long points, whether singly or in combination, are ways the builder attempts to make the transition as smooth as possible so that the force is never concentrated at one point. If the bending force is concentrated at any one point, the tube will deflect there; if the force can be evenly distributed, the whole tube can flex while under stress, but spring back as soon as the bending force relaxes.
When a bike is crashed, head-on, with enough force to bend the frame, the bend(s) typically occur on the top tube and the down tube just after the head lugs. I have seen such bends on a butted frame, where the bend is on the butt itself; that is, on the part of the tube that has thick walls. I don't think I have seen a frame that had actually bent on the lug, or even on a long pointed extension of a lug.
The gorgeous Chris Kvale and Chris Bishop seat clusters shown on the last page make no sense to me. This is not where frames bend.[/
Framebuilders' signature talent and expertise.
Plain and simple.
Their vision of a what a proper road bicycle should look like and ride like.
In the case of Chris Kvale though, we won't have to worry.
I can't imagine he will be building for many more years.
The amount of hand work that goes into his frames is astounding.
I happen to own three of his bicycles, two of which fit me perfectly.
They are absolute jewels to behold, but far more importantly, they are the best riding bicycles I've ever owned.
Bar none.
Durability has never been an issue for Kvale either.
My next door neighbor has a 25 year old Kvale touring bike that rides like the day it was built.