We're taking a flyer on this one but we couldn't resist talking about AIR! True to form, Technical Editor Kevin Cameron starts talking about us breathing and how gravity holds air on the earth ("Which is really good for us.") and we take it from there. Poppet valves, pressure waves, exhaust and intake tuning, and so much more. Ever heard of an Aspin valve? Rotary valve? Sleeve valve? You can say yes to all those if you just have a listen to this week's Cycle World podcast. Join us in the air!