Fenders are there for a reason.

There's a reason for fenders and fender flares beyond just keeping mud from flying about.

Yes, there is the question of aero but the main reason why in most racing series I'm aware of don't allow  tires sticking out beyond the fender lip is one open wheel racers are well aware of.

The contact in this amateur race at Padborg Parkin Denmark is minimal and the speed,  about 80 km/h,  50 mph, not huge.  Yet look how high the rear of the yellow Volvo is launched.

Think of the physics: the downward pushing front half of the Volvo  tire makes contact with the upward pushing half of the BMW's rubber.  You can have fun calculating the finer points of force, speed and angular velocity (CG? ) based on what probably are 18" tires but the result,  one ballistic Volvo and at least one very messed up e36,  show how you cannot take safety gear  for granted, even at club racing level.

Physics does not discriminate.



(thanks @Mikvest )