Mineral oil or DOT standard oil

　　Mineral oil or Dot-approved(department of transportation) brake fluids

　　DOT-3 or DOT-4 is a special brake fluid for disc brakes of automobiles and motorcycles. The composition is to overcome the characteristics of thermal expansion and contraction. The high temperature generated by friction during braking can make the oil boil, evaporate and generate gas. The problem is that gas is easier to compress than oil. When you pull the brake lever, only the gas bubble is compressed, and the piston/brake pad cannot be pushed at all, so that the brake fails or the force is lost! The boiling point of DOT-3 and DOT-4 is lower than that of mineral oil. They are toxic and corrosive. They can melt the paint. The advantage is that they can absorb water and even the water vapor in the oil pot can be eaten. If the oil contains water, the boiling point will decrease. And Cannondale’s Coda disc brake oil is said to be a special formula oil developed by NASA. It is not even afraid of the high temperature during rocket launch, let alone bicycle brakes! Magura first started using mineral oil. Its composition is very pure, although it is non-toxic, it does not absorb water and cannot wash off the paint. The advantage is that the braking force will not be reduced if it is used for a long time or encounters high temperatures. Brake oil should be changed regularly. DOT oil absorbs water, so it is generally recommended to change it once a year. Mineral oil does not need to be replaced so quickly, but once you feel a bit weak in pressure, check it first, maybe it's time to change the oil.

　　 TIPS: The oil used is usually indicated on the manual or the oil can. When changing the oil of the DIY family, please do not make a mistake or mix the two oils. DOT oil will corrode the oil seal of the mineral oil system and vice versa. DOT oil for Hayes hydraulic disc brakes. The Magura system uses mineral oil.