Bart, the guys are definitely on it - can't get a good internal temp on ribs. There's just not enough meat between the bones, and it will never be accurate. Most of us rib folks smoke them by time, and "feel." Once you do a few racks, you'll know the sweet spot with your smoker. I still do the toothpick test, even though I know when they're done by looking at them. If the toothpick goes in easy, that's signal 1. If you can pull the meat sideways, away from the bone without breaking the toothpick, that's signal 2 that they're done! If not, go another 20-30 minutes and check again. With a little practice, you'll "know" when your ribs are just right!