Have you considered using tandem bikes to lose weight? I had the opportunity to ride a tandem bike in the mountain resort a few years back. My sister was in tandem with me. When I would be the one to exert effort, it seemed like I couldn't pedal for the 2 of us. My sister said that the tandem bike is designed for 2 people to pedal.That gets me thinking if the tandem bike is a good way to lose weight?