That was one of many eye-opening experiences I had with the MT43 - when a knobby is half-worn, traction suffers quite a bit; when the 43 is half-worn, only mud traction seems to suffer. They'll still crawl their way up a slick rock face with less than 1/4" of "knob" remaining.. I experience the same thing with regards to wear and PSI. It's very cool to be able to run the same pressure on and off road, no need to carry a pump for the transitions. That right there nails it. I'd personally rather have great traction most the time on the MT43, rather than good traction for a bit, then mediocre and always diminishing traction the rest of the time on knobbies.