Why are NASCAR tires soft?

Answer 1

NASCAR tires vary in compounds, soft, or hardness, by the track they are to be used on, and what for. They used to make a super soft tire, called "gumballs" just for qualifying. Super sticky, but wear out fast. You got better traction for faster qualifying times, but only for a few laps. Ultimately you don't want to make the tire any harder than you have to. The softer, the more grip. But, then, heat comes into play, and tire pressure, sping rate.........Then, if you run some laps, get a caution, then race again with changing them, they react totally randomly because they have been heated, and cooled, which makes them harder. Funny thing, tires. Hard to explain. Softer=better grip. Too soft=heat=slip. Hard=lots of slip=too low tire pressure to compensate=unsafe tire. That's about the best I can do.