Did 2 racks of SLC ribs yesterday. I usually do them at 270 for around 4-4.5 hours and the meat just falls off the bone. After reading some of the techniques, I decided to go with the low and slow - 225 for 6 hours. They were tough and chewy. Very disappointed. I'm guessing they needed more time, but they weren't large? One was 3.8 lbs., and the other mighta been 3 lbs. My first clue shoulda been that the ribs never really pulled back on the bones. Bummed, but I'll go back to a hotter temp next time.