The main reason lugs fell out of favor WAS NOT WEIGHT! It was because of the expense involved, they had to be hand assembled. Plus they now use more aluminum because it's way cheaper than steel, titanium or carbon fiber. These savings were important because in the 80's your LBS and bike manufactures were struggling to make a profit, thanks to the above applications they are once again profitable. With a welded bike a robot with the frame in a jig attacks the soon to be bike zapping it together in about 30 seconds and maybe less. Most custom frame builders agree on two things: 1) lug frames are stronger then a welded frame; 2) lug frames are a bit heavier by about a 1/4 of a pound. Even the older AL frames that were bonded used a lug, and that lug system is stronger then the welds they do on AL frames today; in fact airplane frames are bonded together.
Torelli found a happy medium by lugging the bottom bracket and rear stay but welding the rest. Torelli found that lugs were stronger but also realized they were heavier so they applied the lug where the greatest amount of stress would be. Quote from Torelli: "Lugs. Torelli believes in using lost-wax (investment-cast) parts at all the bicycle's joints. This means that all Torelli frames, with the exception of the Corsa Strada, have cast bottom bracket shells, lugs and fork crowns. The Corsa Strada still uses cast fork crown and seat lugs, but price considerations require that we use bulge-formed head lugs and bottom bracket shells. Investment-cast parts are much more expensive, and it's one of the ways in which Torelli has sought to make a superior bike in ways that do not necessarily show. The cast parts have three basic advantages:
1. They are made with great precision. The fit between the tube and the lugs is exactly right to get the strongest possible bond between the brass, the tube and the lugs.
2. They are stronger. The bottom bracket shell can be made lighter and still withstand the enormous forces of sprinting or climbing. Complex shapes can be cast in such a way as to exactly reinforce the frame where strength is needed.
3. They look much better. Their clean, precise look compliments a framebuilder's finish work.
From:
http://www.torelli.com/home.html?htt...torelli.html&1
see:
http://www.henryjames.com/faq.html
http://www.rivbike.com/html/101_lugs.html
http://www.richardsachs.com/articles/rsachscrown.html
http://www.richardsachs.com/articles/rsachslugs.html
http://www.richardsachs.com/articles/rsachslug1.html