I'm told (and have noticed myself) that Sturmey-Archer AW hubs will sometimes pop into "neutral" between first and second gear, possibly making you sick if you're standing on the pedals up the time. I recall a previous post from someone who mentioned ending up in the emergency room when that happened as he was sprinting up a hill in third gear.
Personally, I will never sprint uphill in third gear, or in second gear for that matter. The only time I can see myself standing on the pedals at all would be in first gear. Is that safe? I've never heard of the popping-into-neutral problem from first. Has anyone else heard of it or experienced it? Is there some mechanical reason why it CAN'T happen?
JV