My "little" commuter bike weighs in at a touch under 48 lbs and has only 3 speeds. My previous commuter weighed only 22 lbs. It took some time for my legs to adjust. Now I am doing well. in fact, when I get on a light weight road bike I feel like I am riding a kids toy and end up manhandling the thing. I would say as others have pointed out you need more recovery time.