My only problem with spinning classes is that they become addictive. When at the gym I would do them in preference to a general workout but I hate to say it but I need that general workout to keep the rest of the body in shape.

Whatever you do- Do not invite any members of the class for a ride. They may be able to tan your butt on the spinning bikes- but if you ever get them out on a real ride- you will be carrying them after 30 miles.