The 2021 Cadillac CT4 tire size depends on trim: the Luxury, 4WD takes 225/45R17 91V; the Luxury, RWD takes 225/45R17 91V; the Premium Luxury, 2.0L Eng VIN K, 4WD takes 235/40R18 91V; the Premium Luxury, 2.0L Eng VIN K, RWD takes 235/40R18 91V; the Premium Luxury, 2.7L Eng VIN L, 4WD takes 235/40R18 91V; the Premium Luxury, 2.7L Eng VIN L, RWD takes 235/40R18 91V; the Sport, 4WD takes 235/40R18 91V; the V, 4WD takes 235/40R18 91V; the Sport, RWD takes 235/40R18 91V; the V, RWD takes 235/40R18 91V, per the factory service manual.
Factory-Spec Tire Size
Varies by trim
Luxury, 4WD: 225/45R17 91V
Luxury, RWD: 225/45R17 91V
Premium Luxury, 2.0L Eng VIN K, 4WD: 235/40R18 91V
Premium Luxury, 2.0L Eng VIN K, RWD: 235/40R18 91V
Premium Luxury, 2.7L Eng VIN L, 4WD: 235/40R18 91V
Premium Luxury, 2.7L Eng VIN L, RWD: 235/40R18 91V
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