I recently lost 20 pounds (158 lb down to 138 lb) riding an exercise bike; it is a nothing-too-fancy Proform 920 S EKG that I bought used on Craigslist for $50. I wasn't exact overweight to start with. I'm male, 5'8"; was just carrying a little spare around the belly. My body fat went from 18% to 11%.
Since I've been riding the exercise bike a lot, I'm starting to notice a few things malfunctioning on the exercise bike. The digital display is totally shot/illegible, but I can still control the intensity level from 1 to 10. Then I got to thinking, since the difficulty of the machine is controlled by the position of the magnet to the flywheel - closer, more difficult to ride; farther, easier - why do they still need to build exercise bikes with a chainring connected to the flywheel via a belt? That is, why don't the maker just have the user pedal directly onto the flywheel, saving parts and money, reducing the number of things that can go wrong? The rider should be able to pedal, as usual, except the crank is built into the flywheel, and the magnets are positioned just the same as before to control the difficulty. Less part to worry about, less things that can go wrong, smaller and more compact machine, win-win for everyone...
Can anyone tell me why?