I have a Trek 5200, about 8 years old, that I just upgraded the original Ultegra cranks to new Dura Ace 7700 (9 speed) cranks and Ultegra bottom bracket. On my old setup there was a thin metal washer on the drive-side of the bottom bracket, between the actual frame and the BB cartridge. They did not replace this washer when it was installed at my LBS. I have all the old parts, including the washer. What does this piece do? Do I need to have them remove the cranks and BB to re-install this part? Thanks.