Miguel Indurain and Pinaello weren't the first to do this dropped top bar. On the pro scene it was first done by Edwig Van Hooydonck and Colnago back in the time of Super Confex in the mid to late 1980's. Most of the pro teams back then used Campagnolo and seat posts only came in short lengths not like today, so for tall riders like Van Hooydonck getting the seat higher was a problem. Colnago also realised this and solved the flex of a rider's large frame by just dropping the top tube to create a smaller diamond. Concorde also adopted the theory for riders such Steven Rooks and Gert-Jan Theunisse.
Miguel Indurain and Pinaello weren't the first to do this dropped top bar. On the pro scene it was first done by Edwig Van Hooydonck and Colnago back in the time of Super Confex in the mid to late 1980's. Most of the pro teams back then used Campagnolo and seat posts only came in short lengths not like today, so for tall riders like Van Hooydonck getting the seat higher was a problem. Colnago also realised this and solved the flex of a rider's large frame by just dropping the top tube to create a smaller diamond. Concorde also adopted the theory for riders such Steven Rooks and Gert-Jan Theunisse.