Two types of oils are used for the hydraulic brakes of bicycles: Mineral oil and synthetic oil.
We find this oil mainly used by manufacturers Shimano and Magura on bike ranges road. It has the advantage of being stable over time, requiring, in theory, less change or purge. It does not generate condensation.
Dossier: Disc brakes Shimano: Technologies for road bike
It is not corrosive and does fall on a painting has no effect without damaging it.
It has a reduced efficiency on very high temperatures. It is usually colored it can detect faster leak.
This oil is used by most brands including SRAM for road cycling. It offers excellent resistance to high temperatures. We talk about DOT: Department of Transportation. In the middle of the cycle, there are mainly the DOT 4 and DOT 5.1 which is resistant to temperatures up to 250 ° C mounted.
Dossier: hydraulic disc brakes SRAM road bike
In theory, SRAM found that the DOT 5.1 met 2 times longer to reach the boiling point than DOT 4, thus allowing superior performance in extreme conditions.
It is yellow and so it is less easy to detect leakage. This oil, synthetic therefore, is relatively corrosive and attack the different paint or varnish frames on which it is leaking. So be relatively vigilant when purging or leak.
This synthetic oil generates water within the system because it picks up moisture. And when water is in the system, the DOT water mixture and form gas which can make the hydraulic brake system off.
This oil therefore requires maintenance by more regular purge.
How to choose hydraulic oil?
It’s not that you are choosing a mineral or synthetic oil. It is indeed, the manufacturer of your group using an oil or another. As mentioned, for example, uses Shimano mineral oil and synthetic oil SRAM.
It is absolutely impossible to substitute mineral oil to synthetic or reverse the damage these joints in the system for sealing!
The oil to be used is, in addition to being recommended in the manual, is usually written on the levers at the place where come to connect the syringe to perform purging.
Feature: Hydraulic disc brakes for road bikes