There's a 60 deg F difference!
And... there's only about a 12 inch difference between where the lid thermometer is and where the Maverick thermometer probe is
located under the grate right below the meat. If I were to go by the lid thermometer temperature, it would read the proper 230 deg
F, but the temperature at the grate would only be 170 deg F. It would take about 12 hours to cook these ribs at 170 deg F! And most people would pull them off way before 12 hours. The result would be tough ribs that you would have to
gnaw on to get the meat off the bone. But... your dog would love them! What you are shooting for is tender and juicy meat that sticks to the bone but pulls clean when bitten - and does not fall off the bone.
Of course, the temperature at the grate eventually rose to about 230 deg F after about an hour. Note here that it took a whole hour for the cooking chamber temperature to come up to the proper temperature. So that's your second adjustment - just give it more time. It will take more time to get your smoker up to the proper temperature and every time you open the lid (only when absolutely necessary), you'll lose more heat than usual. And it will take more time to recover.
I also took some pictures of proper smoke examples... the first picture below shows what bad smoke looks like. It's a white billowing smoke. This usually happens when you smother your fire by throwing too much new fuel on at one time. It can also happen if you close your vents too much and smother the fire. Proper smoke is showed in the second picture - it's a light blue in color and almost invisible.
Since you can't always go by time in cold weather, you'll have to know what signs to look for when the ribs are done... notice the meat pulling away from the bone in the picture below. That's a sure sign that your ribs are getting done. You can also use a toothpick to check for tenderness between the bones. And... if you pick up one end of the slab with tongs and the other end bends down 90 deg, you'll know for sure they are done. Note that done full slabs of spareribs don't bend as easily as St Louis cut or baby backs so maybe a bend somewhere between 45 deg and 90 deg is OK.
Results (judging): The ribs had a great flavor. Sort of a spicy sweet combination. There was more "bark" than most people would like, but I don't mind a good tasting bark - and remember, these were cooked "Memphis Dry Rub" style and this style is going to naturally produce more bark. The meat was tender and juicy and stuck to the bone but pulled clean as it should. Overall, I would say they were pretty darn good!
I hope this helps you out with your rib smoking! For even better tips, make sure you get our book, "Competition BBQ Secrets"!