The Continental's are ~0.8" smaller in diameter. The smaller diameter will introduce a small speedo error, in this case about 2% (1.2mph @ 60mph). Make sure the Continental's have the same or higher load rating as the Michelin's. Also need to consider the Continental's are about 3/4" wider.
Tire diameter calculation: (235/80R 22.5)
What the numbers mean: 1st number is tire width in millimeters, 2nd number is aspect ratio of tire height to width (percentage), 3rd number is wheel diameter.
Sidewall width divided by 25.4 (convert millimeters to inches)
Tire height = Sidewall width multiplied by aspect ratio (80 = 80% or 0.8, 70 = 70% or 0.7)
Tire diameter = tire height times 2 plus wheel diameter (TH * 2 + 22.5).
Tire circumference = diameter * pi (3.142)
Revolutions per mile:
Convert tire circumference to feet by dividing by 12
Divide 5280' (number of feet in a mile) by tire circumference
Good luck with your decision,
2011 Itasca Meridian 34Y
2006 Jeep Liberty