Which type of brake fluid is considered synthetic?

The choice of brake fluid categorized as synthetic is DOT 5. This type of brake fluid is silicone-based, distinguishing it from the other options, which are glycol-ether-based fluids. DOT 5 is particularly advantageous in high-performance or specialized applications because it offers a higher boiling point and better resistance to moisture absorption compared to other types. Also, DOT 5 fluid does not mix with water, reducing the risk of corrosion and ensuring that the brake system maintains its integrity over time.

In contrast, DOT 2, DOT 3, and DOT 4 fluids are all glycol-based and designed for standard automotive braking systems. These types tend to absorb moisture from the air, which can lead to a decrease in boiling point and potentially create a hazard in braking performance. DOT 3 and DOT 4 fluids, while they serve different performance levels, still fall under the glycol category and thus do not possess the synthetic qualities that DOT 5 does.