Why the different brake fluids?
Brake makers decide what characteristics their brakes should have and specify the best fluid for the job. There are two main types of fluid – mineral oil and glycol based which are commonly called DOT (3, 4 or 5.1) brake fluids. The higher numbers are given to fluids with higher boiling points. There is another fluid – a silicone based DOT 5 which is not used as a bicycle disc brake fluid. You MUST, unless you’re willing to risk your brake’s seals, stay with the recommended fluids. Read the manual! Here’s another major difference – DOT brake fluids dissolve paint and mineral oils don’t.
