dmtroyerThey're too baggy for biking...you're more than likely going to get it caught in the chain and given the lightweight fabric this uses that'll pretty well kill 'em. Don't get me wrong they're good rain pants (and lasted an entire AT thru-hike), but it's very light fabric, so it won't tolerate much abuse.
Also, you can forget about the "breathability", I'm convinced that there's no such thing as a breathable (to any discernible degree) waterproof fabric. I would recommend most folks to get a good pair of hiking pants (Fjallraven or equivalent) and just wax them unless it's cold enough to justify wearing these.