Portland has long been thought of as a cycling mecca for one big reason: Affordable homes were close enough to work to commute by bike. Housing prices rose by another 6.6 percent last year, and a February project by Governing magazine found the city is gentrifying faster than anywhere else in the nation. Does the promise of an affordable, bikeable Portland still hold up?Consider that the median income for a family in Portland is around $50,000, which financial advisers will tell you means they should not spend more than $315,000 on a house. Also consider that the national average commuting time is 25 minutes each way.