Originally Posted by
bud16415
Don’t get me wrong I'm not advocating such a device in fact I pointed out that exact same thing in a previous post. Nonetheless many of the modern innovations of today's road bikes started out with some heavy roots. There is a big difference in some guy building a prototype of an idea in his shop and what the refinement could end up being 20 years down the road. Even the first Ironman was a little on the heavy side.
Flywheels have a lot of great applications
http://en.wikipedia.org/wiki/Flywheel_energy_storage
A bike isnt one of them. The problem is that a flywheel works because it has a lot of mass. There is no way to make it lighter. That's why cars use lithium batteries and electrical energy storage.