為何全世界的車輪都是黑色的?

係因為輪胎入面加左一種叫 Carbon Black 既野

Carbon Black 係一種未完全燒完既石油(incomplete combustion of petroleum),加入輪胎可以加強輪胎既耐力同壽命,減低磨損,而Carbon Black係黑色既

這是輪胎的成份:
• Natural Rubber, or Polyisoprene is the basic elastomer used in tire making
• Styrene/Butadiene co-polymer (SBR) is a synthetic rubber which is often substituted in part for natural rubber based on the comparative raw materials cost.
• Polybutadiene is used in combination with other rubbers because of its low heat build up properties.
• Halobutyl Rubber is used for the tubeless inner liner compounds. The halogen atoms provide a bond with the carcass compounds which are mainly natural rubber.
• Carbon Black, forms a high percentage of the rubber compound. This gives reinforcement and abrasion resistance.
• Silica, used together with carbon black in high performance tires, as a low heat build up reinforcement.
• Sulphur cross-links the rubber molecules in the vulcanization process.
• Accelerators are complex organic compounds which speed up the vulcanization.
• Activators assist the vulcanisation. The main one is zinc oxide.
• Antioxidants prevent sidewall cracking, due to the action of sunlight.
• Textile fabric reinforces the carcass of the tire.

carbon black 應該係主因

你想問的應該是車的輪胎吧。
輪胎主要由合成橡膠（Synthetic rubber）造成，內裡也會加入鋼線以加強其堅韌度。
合成橡膠是石油製成品，用以代替天然的橡膠。雖然兩者質地差不多，但顏色就十分不同。天然橡膠一般是乳白色的，而合成橡膠由於是石油製成品，並加入硫（sulphur)進行硫化作用，因此其色澤是黑色的。

because the raw materials are black !!