10 cars are parked around for the party, 10 x 4 wheels each car = <<10*4=40>>40 wheels total.
Dylan's parents both have a car with 4 wheels each, 2 x 4 = <<4*2=8>>8 more wheels.
Combined, there are 40 + 8 = <<40+8=48>>48 wheels total on the Dylan family property.
#### 48