The chemical process of vulcanization is a type of cross-linking that changes rubber to the hard, durable material associated with car and bike tires. This process is often called sulfur curing; the term vulcanization comes from Vulcan, the Roman god of fire. This is, however, a slower process. A typical car tire is cured for 15 minutes at 150 °C. However, the time can be reduced by the addition of accelerators such as 2-benzothiazolethiol or tetramethylthiuram disulfide. Both of these contain a sulfur atom in the molecule that initiates the reaction of the sulfur chains with the rubber. Accelerators increase the rate of cure by catalysing the addition of sulfur chains to the rubber molecules.