I just did this today, for the first time. While my Orca has roughly 2.5" drop from seat height to bar height, my Roubaix was set up w/ zero drop. I had 4 spacers below- 2 thins (.5cm) and one thick (1cm). After 3 months on the Orca, the set up on the Roubaix felt like a beach cruiser. So, today I left one thin spacer below and moved the other thin and the thick above. Felt OK riding around the block. Will know better next time I really ride it.