The gravel surface is also a very unique and challenging surface type used in iRacing and in the real world. This surface type is known affectionately as the "Telford Surface" due to the aggregate, gravel, stones and other things that go into a gravel surface which prevents water collection and surface corrosion on the race surface. This surface is known for having a very small grip availability while the many other surfaces have a wider grip availability. While the acceleration, jumping, and drifting action make the racing more exciting, competitive, and a lot more entertaining, it makes the track more unforgiving than the dirt surface but does not sacrifice tire grip and tire wear although pit stops are not carried out on this surface type. The speed on a gravel surface is much lower than on any other surface type due to the short and technical tracks that are a characteristic trait of these tracks.
Pros: This surface has the Telford affect where the water collection and surface corrosion on the racing surface is eliminated entirely. Also the acceleration, jumping ,and the drifting action on the gravel surface type makes the action more exciting, competitive, and more entertaining. The tire grip and tire wear are not scarified although pit stops are not carried out on this surface type.
Cons: A negative of the gravel surface type is that the grip availability is very small compared to most racing surface types. The track is also more unforgiving than most other surface types and the lower speeds are of course a safety necessity. Also, 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 Gravel Surface:
Grip: 4/10
Longevity: 10/10
Merciful: 4/10
Speed: 4/10
Tire Wear: 10/10
Overall: 32/50 (64%)