jimlews wrote:Re: 1. Lugs serve a rather different function to that of the "gusset"which is a reinforcement. Lugs are just a convenient way of joining the tubes. It is the accurate mitering of the tube ends that is the important thing. That and complete penetration of the brazing material. Lugs were routinely filed to reduce the step ratio between the tube and the lug and thus reduce the risk of introducing a stress riser.
The point remains that they are quite different methods of joining tubes, and are likely to have different failure modes, as illustrated by the posts above. Inferring that the gusset is not necessary because for generations frames had no such reinforcement, when those frames were overwhelmingly lugged, is specious logic.
jimlews wrote:Re: 2. 'a gusset on most - possibly even all'... suggests that it is needed...
It could equally suggest that either all those frames are made in the same Taiwanese factory or it is merely the current fashion accessory.
Contract frame manufacturers will make whatever someone pays them to. They will not be concerned if a brand orders a batch of frames with an inherently weaker design that they suspect - or know - will result in an unacceptable number of breakages and returns, because it is not their reputation that will be damaged and they will not have to pay for replacement frames. They might query the order in the interests of maintaining a good customer relationship, to give the brand the opportunity to change the design, but that would probably be the most they would do. Similarly they will not do anything that the brand has not requested - the order could be rejected, and adding a gusset will increase the cost of a frame.
jimlews wrote:Re: 4 How could you possibly know that? I haven't put a name to the frame.