Motorcycle brake fluids are a type of hydraulic fluid used in motorcycle braking systems. They are designed to transfer pressure from the brake lever or brake pedal to the brake calipers, causing the brake pads to clamp on the rotor and slow or stop the motorcycle. Brake fluids are typically glycol-based and must meet certain performance specifications, such as boiling point and viscosity, to ensure safe and effective braking. It is important to use the right type of brake fluid for your motorcycle, according to the manufacturer's recommendations, and to regularly check and replace the fluid as needed to maintain proper braking performance.
Brake fluids are classified in the most common way, abbreviated by the DOT (U.S. Department of Transportation). According to this classification, brake fluids for motorcycles are categorized as DOT 3, DOT 4, DOT 5, DOT 5.1. The main differences between these types of brake fluids are their chemical composition, resistance to water absorption and boiling point.
The DOT 3 type fluid contains chemical compounds of glycols. Its boiling point is about 205°C when the fluid is dry. This type of brake fluid is recommended for scooters and small motorcycles.
DOT 4 and DOT 5.1 brake fluids consist of polyethylene glycols and boric acid polyesters. These are high-quality fluids that withstand extreme conditions, proving their effectiveness in any situation. The boiling point of DOT 4 is at least 230°C. For DOT 5.1, the boiling point is a minimum of 270°C. This fluid can be used in high-performance sports motorcycles, even during racing.
DOT 5 fluid is a silicone-based fluid and is significantly different from other types of brake fluid, so mixing DOT 5 with other types is strictly prohibited. If you decide to change from DOT 5 brake fluid to another type, you must flush the system thoroughly.
The frequency of replacing brake fluid in a motorcycle depends on several factors, such as the type of motorcycle, type of use, road conditions, etc. Motorcycle manufacturers usually state the recommended frequency of brake fluid replacement in their manuals. These recommendations vary from model to model and can vary from a few years to several years or mileage.
If the motorcycle is used in harsh conditions, such as off-road driving, riding on wet roads or heavy braking, the brake fluid should be changed more frequently. It is also recommended that the brake fluid level and condition be checked regularly to detect any imperfections or abnormalities early.
Using the wrong type of brake fluid in a motorcycle can have serious consequences. Different types of brake fluid have different boiling points, and using brake fluid with a lower boiling point can cause your brakes to fail due to blockage.
In addition, using brake fluid that is incompatible with the materials in the brake system can cause corrosion and damage to brake components, leading to reduced performance and even complete failure of the brake system.
Moreover, using the wrong type of brake fluid can void a motorcycle's warranty. It is important to use the specific type of brake fluid recommended by the manufacturer, and to check and replace the fluid as needed to ensure proper performance and longevity of the motorcycle's brake system.
To check the brake fluid level in your motorcycle, follow these steps:
Note: Make sure you use the recommended type of brake fluid specified by the manufacturer and keep the cap tightly closed to prevent contamination of the brake system.