hi brant tried them with 40psi as recommended by on one dropped them to 36 and they still did not work. last sunday the front washed out 3 times the last one had me off. not experienced that all through this winter and the last british summer.they bare fitted to ztr flow rims on a 2012 ellsworth moment. I was out yesterday with a conti mk( the entry level one)and the front was way better than the chunky monkey was and the conditions were a lot worse than sundays ride.I left the smorg on the back and it just would not hook up at all. as for being able to tell the difference- well i cant say that i can tell the difference between the cont rubber queens that i have run and the mountain kings but i could certainly tell the difference between the mk and the chunky monkey- like night and day