Originally Posted by dmatter

We do it because we want worn out pins with fresh foams inside. At our track we run Pink Tapers and you need about 3 or 4 different pin heights for the changing conditions. More dust=more pin, when it is wet and tacky we almost run slicks or very worn pins. When you stuff new foams in the worn out tires they are DIALED! Blown out foams=no traction.