Many excellent bike shops in Southern California already sell e-commuters, with more retailers adding them their inventory every month. So then why would anyone want to assemble a do-it-yourself (DIY) e-bike when there are scores of superb OEM models available? The reasons, many and varied, include the cost savings, the assurance that the conversion of a bike that already fits you perfectly will continue to do so as an e-bike, a new hobby, the feeling of accomplishment and an intimate knowledge of the functional parameters of your bike.