Why vulcanize rubber?
Rubber has long, tangled molecules that allow it to be stretchy but, the links are weak by themselves. When it gets hot, it melts easily and, when it gets cold, it hardens quickly. Vulcanizing, or cooking, the rubber with sulfur creates cross links in between the rubber atoms as shown below. These cross links make covalent bonds which allow rubber to be used in a practical sense. The rubber retains its elasticity but, it's less susceptible to changes in temperature. It's also more durable which then allows significant weight to be placed on it. With this in mind, the main components of any car can be assembled and placed on the tires which then roll, propelling the car forward or backward. When the surroundings are hot, the bonds in the rubber of the tires become looser which creates a bigger contact on the road which generates more friction on the road. This frictional force in turn creates more speed for cornering. Tires affect their cars more than they would think.
Polyisoprene - (http://www.wikiwand.com/en/Vulcanization)
Rubber by itself is a weak substance but, when vulcanized with sulfur, it becomes something that is essential for creating things that we use daily. The sulfur creates cross links that make stronger bonds between the polyisoprene atoms, making rubber practical. Like many inventions before it, vulcanized rubber was accidentally discovered by an ambitious inventor(Charles Goodyear). Without it we wouldn't have cars today.
1. VulcanizedRubber - http://historythings.com/historical-inventions-that-were-created-completely-by-accident/
2. Pirelli F1 Tyres - https://www.youtube.com/watch?v=sn3AcqpXe7c
3. Charles Goodyear - http://www.biography.com/people/charles-goodyear-9315611#synopsis
4. Hevea Brasiliensishttps - ://commons.wikimedia.org/wiki/File:Rubber_trees_in_Kerala,_India.jpg (Self published by M.arunprasad)
5. Polyisoprene and Sulfur - http://www.wikiwand.com/en/Vulcanization