A common modern method of production involves the controlled burning of a hydrocarbon, such as acetylene. Carbon black is produced in a variety of grades that differ in particle size, and in the size of aggregates of the single particles. Carbon particles and aggregates are used to coat the individual polymer strands of both synthetic and natural rubber. Which variety of carbon black is used in a particular tyre depends on the desired result. The amount and size of the particles added can lead to rubber that is very soft or that is very hard, which can affect the ride of the tyre and its wear.
Softer tyres grip better in wet weather but wear out sooner than harder ones.
Modern tyres are given a particular set of properties by adding carbon black particles of six or more different sizes and aggregation parameters. Not all latex is white. The tree species Sebertia accuminata occurs on ultramafic rock in New Caledonia and has bright green sap due to the very high levels of nickel, up to 26 per cent, in the soil.