Re: What is the best bike to build to sell?
I think the best bikes to motorize from a purely functional and value point of view are older steel mountain bikes. You can pick up older quality mountain bikes (Trek, Specialized, etc) for not much, They have strong frames, the steel ones have the smaller diameter tubing that makes it easy to mount the engine, strong wheels, and good quality effective V or center pull brakes. It's also pretty easy to install a new hub with a disk brake mount that you can use to attach the rear sprocket if you're concerned about that. Unfortunately, an old mountain bike with a motor isn't the most stylish ride in town.