Por si a alguien le interesa, he encontrado la respuesta: "Became 600EX when indexing was introduced, 600 Ultegra (Gray finish) when 7-speed added. When it became an 8-speed group, the 600 designation still existed, but it was usually referred to as just "Ultegra". With the '98 model year, 9-speeds came in and the "600" designation was completely dropped from Ultegra." Así que 1998. Un saludo
se presento en 1997, lo se porque aun tengo por aqui la Bicisport de Agosto del 97 y viene un articulo sobre el Ultegra de 9v
