In my experience at least, wellgo pedals are crap. The bearings just don't last, and they don't seem to have as much float as Shimano SPDs. If I were you, I spend a few extra bucks and get Shimano SPD 520 pedals. You can get them at ProBikeKit for $28 shipped.
http://www.probikekit.com/display.php?code=d1013

They last long and are fully serviceable.