The new Tread Flex solves two obvious barriers to treadmill ownership: space and price. Peloton’s Miley launch ad somehow makes both easy to miss. My wife and I are unusually great prospects for Peloton’s new Tread Flex. We’ve owned Peloton bikes for seven years, and use the system almost every day. A treadmill would expand what we can do, but we have no appetite for permanently surrendering that much floor space to one. Then Peloton announced its first folding treadmill. The new Tread Flex...