Lightweight is a brand of CarbonSports GmbH based in Friedrichshafen on the picturesque shores of the Bodensee (Lake Constance to you) in Southern Germany. Many a European cycle dealer will have fond memories of Friedrichshafen from visiting the Eurobike show - which often claims to be the largest bicycle related trade fair in all the world. You can certainly spend a many a pleasant hour there, gazing wistfully across the lake at the distant snowy peaks of the Swiss Alps, while patiently waiting in the mother of all traffic jams caused by tens of thousands of salivating, dreadlocked-German-bike-geek-dudes flocking to get their annual fix of CNC machined component porn.
The Lightweight web site credits the formation of the brand to Heinz Obermayer and Rudolf Dierl who developed full carbon wheels in their garage ‘near Munich’. Strangely, the patent record shows one Monika Dierl and Heinz Obermayer and as having applied for their first patent relating to carbon wheels in 1988. Rudolph’s name doesn’t appear on relevant patents until 1993. In the 1988 patent Heinz is listed as living in Munich, but Monika lives in Dachau which is, of course, ‘near Munich’ and may be the site of the legendary garage. I might guess that Dachau is a charming suburb, with clean public parks, good local schools and low property taxes, but its history may just be a touch too toxic for its name to be allowed to appear in advertising material.
What is unarguable is that by 1995 Lightweight had a spectacularly successful wheel design, used to win the Tour de France with Bjarne Riis in 1996, Jan Ullrich in 1997 and kind-of-win-it with Lance Armstrong in 2001.
In 2003 the Lightweight brand was sold to CarbonSports GmbH.
In 2005 CarbonSports introduced a full carbon Lightweight derailleur, costing a mere $1,100 and weighing just 120g. I believe that it was available in two versions, one for 9 & 10 speed Shimano and the other for 9, 10 and 11 speed Campagnolo. I have only ever met one person who had used one of these derailleurs (a Campagnolo version) and they swore that it shifted peerlessly.
I have a sense that production of the derailleur ended in about 2012, but I have no evidence for this date. There is no obvious presence of it on the Lightweight web site today (2015).