|MadSci Network: Chemistry|
There are several kinds of friction in tires. The two most common are rolling resistance and ground friction. I'll assume you are concerned with ground friction for this answer. Normal tires become more flexible as they warm. This means that there is more of the tire tread contacting the ground and higher friction. In drag racing, the tires have a high percentage of polyisoprene in the formulation. When the drag racers drag out prior to a race, much of the polyisoprene reverts and becomes tacky. This tackiness also increases the friction between the tire and ground. The trade off is that drag racing tires have a very short lifetime. Hope this helps.
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