As convenient as ridesharing and app-based taxi services can be, you still have to wait for your lift to show up. Wouldn't it be nice to hop into the first available taxi and then pay through an app? Flywheel is trying just that. Its new Pay by Flywheel service lets you hail a taxi and pay after you're on your way -- the app uses your phone's motion sensors to tell when you're in mid-ride. It's theoretically just as speedy as flagging down a conventional taxi, but saves you the hassle of fumbling with your wallet at the very end. The option is available today in every Flywheel area, including the just-added city of Portland.