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Motul RBF660

Motul RBF660

Regular price $31.95 USD
Regular price Sale price $31.95 USD
Sale Sold out
Racing Brake Fluid 660 - 100% Synthetic Fluid - DOT 4 -

- One of the highest dry boiling points on the market: 617℉ (325℃).
- Ultra-efficient in the rain with a very high wet boiling point: 400℉ (204℃).
- Mixes with DOT 3 and 4 systems (Not DOT 5).

Specially designed to resist to high temperature of racing actuated brake (steel or carbon) and clutch systems.
Exceeds DOT 5.1 and DOT 3 standards

Is RBF660 right for you?

We know it's difficult to choose parts for your car sometimes, so we thought we'd make it easier by offering a concise selection guide for Motul's brake fluid products

If you only ride your bike on the street, are not overly aggressive on your brakes, or don't want to flush your brake fluid more than once every one to two years, we recommend Motul's DOT 5.1 fluid. It absorbs water very slowly and has high dry and wet boiling points compared to most DOT 3 and DOT 4 fluids.

If you ride your bike aggressively on the street, ride lots with heavy braking or do track days occasionally, Motul's RBF600 is the fluid for you. It will last at least a year under normal street riding conditions before needing to be flushed, and has extremely high dry and wet boiling points - much higher than DOT 5.1.

If you're still boiling Motul's RBF600, it's time to consider RBF660, Motul's highest performing brake fluid. It absorbs water very quickly compared to RBF600 but in exchange has an even higher dry boiling point. If you know you need extreme temperature resistance RBF660 is the only way to go.

Compared to other Motul brake fluids?

Compared to Motul's DOT 5.1 brake fluid, RBF600 has higher dry and wet boiling points, but shorter lifespan. It is expected that RBF600 will need to be flushed about twice as frequently as DOT 5.1.

Compared to Motul's RBF660 brake fluid, RBF600 has a lower dry boiling point and a slightly higher wet boiling point. It also has marginally better longevity, needing to be flushed at about the same frequency as RBF660, if not at slightly longer intervals.

Dry and wet boiling points? That doesn't even make sense!

In this case, consider dry versus wet as the amount of water something contains. Brake fluid is considered dry when it is pure glycol and uncontaminated by water. It is considered wet when it is contaminated by a certain percentage of water - usually around 4%. This standard comes from a DOT study of the average amount of water absorbed by average brake fluids after one year.

By the way, some vendors claim that the high wet boiling point means the fluid performs better in rain - this is simply not true. Your brake system is a sealed unit and the external humidity has only a small contribution toward the fluid absorbing water. If your car is exposed to extreme humidity on a constant basis, it will make a difference over a long period of time, but not in an isolated situation wherein it might or might not be raining.

As such, when Motul brake fluid is brand new and in an unopened container, it is at its dry boiling point. After some time spent in your car's brake lines, the fluid will begin to absorb water through minuscule leaks in the master cylinder, brake line fittings, and so forth, and when it reaches 4% water saturation it is at the wet boiling point.

We recommend flushing your brake fluid at one year intervals at least, as once the brake fluid reaches a certain water saturation the water will begin to boil separately, causing the pedal or lever to compress substantially more than normal. For more extreme fluids such as RBF600 and RBF660, it is best to change the fluid more frequently to keep the performance benefits of these high temperature fluids.
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