even at the go cart vs. motorcycle level, the go cart can corner far better than the motorcycle.
If a car can't corner faster than a motorcycle, then the driver is either chicken or they have a really bad car with bad suspension and tires.
Full size cars have the disadvantage of not being able to use as much of the track as motorcycles, so a motorcycle can make its effective turning radius much wider than a car, which takes up some of that real estate with the width of their vehicle. Look up lap times for the tighter road courses (such as Streets of Willow) to see the difference.