The dirt surface is also a very popular surface type used in iRacing and in the real world. This surface type is known affectionately as the "Loose Stuff" due to the speed, powerslides, and turning right to go left action that is so well-known on a dirt surface. This surface is known for having a wide grip availability which the concrete surface has a bit lesser of but has a bit less grip availability than what the asphalt surface has. While the speeds, powerslides, and turning right to go left action make the racing more exciting, competitive, and a lot more entertaining, it makes the track more unforgiving but does not sacrifice tire grip and tire wear which can lead to much longer pit stops. The speed on a dirt surface is much lower than on the asphalt and concrete surface types due to the very short length that dirt tracks often have.
Pros: This surface has a wide grip availability thats wider than the concrete surface type but not wider than the asphalt surface type. The loose surface allows for powersliding and turning right to go left action for all drivers that compete on the dirt. The surface also leads to more exciting, competitive and entertaining races for the fans, sponsors, and much more. Another positive is that tire grip and tire wear lasts much longer than any other racing surface type.
Cons: A negative of the dirt surface type is the lower speed restrictions to ensure safety of the high powered dirt cars around the tiny dirt tracks. The dirt surface type also makes the track more unforgiving if a driver's racing line is not spot on for the entry, apex, and exit of the corner or if a driver does not have the right car inputs to get around a dirt track cleanly and consistently.
These are the 5 categories for rating a surface type in iRacing:
Grip (how much grip that surface type has, 0-4 is low grip, 5 is neutral, 6-10 is high grip)
Longevity (how far a driver can go between pit stops, 0-4 is short, 5 is neutral, 6-10 is long)
Merciful (how forgiving it is, numbers from 0-4 are unforgiving, 5 is neutral, and 6-10 is forgiving)
Speed (how much speed can be carried on the surface type, 0-4 is slow, 5 is neutral, 6-10 is speedy)
Tire Wear: (how much it wears down the tires on the car, 0-4 is quick, 5 is neutral, and 6-10 is slow).
Rating of Dirt Surface:
Grip: 7/10
Longevity: 9/10
Merciful: 4/10
Speed: 5/10
Tire Wear: 9/10
Overall: 34/50 (68%)