(Portland, OR)  --  Bike shop owners in Portland could face big losses if lawmakers approve a proposal to place a five-percent tax on the purchase of new adult bicycles.  The five-million-dollar plan was proposed on Monday to fund roads, bridges, and bike projects.  The owner of Crank in Southeast Portland told KATU-TV that bike shops would take the biggest hit from the tax because they would need to absorb it to keep prices competitive.  Some cyclists argue it's unfair to tax bicycle riders when they probably also own cars and already pay taxes for road repairs, while others say they should pay their fair share.  It's not clear where the extra funding would actually go.