Does MTB Brake Fluid Freeze? (Things You Must Know)

Does MTB Brake Fluid Freeze

Brake fluid refers to a type of hydraulic fluid frequently used in hydraulic disc brakes and hydraulic clutch devices used in vehicles such as automobiles, motorbikes, light trucks, and even a certain kind of bicycle.

The braking force and overall performance are amplified by successfully converting force into pressure.

The theory is based on the fact that liquids, unlike gases, are not easily compressed.

Therefore, most brake fluids have a glycol-ether foundation. However, MTB brake fluids are also based on mineral oil and silicone.

Silicone-based brake fluids are becoming increasingly popular. Brake fluid has several uses in a car and is also quite durable.

MTB brake fluid does not freeze as quickly as other liquids, such as water. But, in any case, it can reach a point where it can get so thick that it is no longer effective as a force transmitted from the master cylinder down to the car’s wheels.

Does MTB Brake Fluid Freeze?

No, MTB brake fluid does not freeze. However, when it comes to the upkeep of your mountain bike, the cold weather may be a real pain for owners who reside in frigid locations and ride their bikes often.

Additionally, when there is a significant amount of moisture present and low temperatures all around, it may be a headache to think about everything that has the potential to go wrong.

You may have thought about the prospect of your brake fluid freezing as one of these potential problems.

MTB Brake fluid is a vital component of any braking system since it begins most of the operations leading up to your motorcycle stopping.

However, even if you apply certain additions to increase its performance, it can congeal at temperatures as low as forty-two degrees Fahrenheit.

It doesn’t take more than a few minutes for the brake to heat up and fix the problem while driving.

Adding some chemicals to braking fluids can raise their freezing point, while water has been found to reduce freezing points for certain substances for whatever reason.

What Happens When Brake Fluid Freezes?

Brake fluid does not freeze in cold weather, as we know. However, If the temperature dips below freezing, several other things will occur.

Let’s take a closer look at each of them.

#1. Brake Line Weakens

When the weather becomes cold, the brake fluid loses some of its tensile strength.

If this scenario remains unchanged and the point brake fluids continue to be subjected to such severe elements, it will cause the brake lines to wear down over time and create cracks and rips if they are exposed to such extreme conditions.

Cold temperatures do not freeze the braking fluids in the lines since they are made of a different material than water. Read more about Tire Sealant Freeze.

Therefore, even in the harshest of winters, brake lines will not freeze. They will only congeal at greater temperatures than usual if they are tainted.

On the other hand, if we are talking about turning into a solid block of ice, this will not happen until you find yourself living in the northern regions of the globe.

Oils are used in brake fluids; therefore, they’re found in the braking system’s lines.

#2. Brake Begins To Congeal

There is a point at which the brakes begin to thicken when the temperature drops below -forty-degree celsius.

However, the oil brake fluid does not turn into icicles even at this low temperature.

Conversely, thickening is not a preferable alternative to freezing since the automobile will not have the ability to stop effectively.

In addition, when the brakes congeal, they generate grinding and screaming sounds when driving.

#3. Brake Starts Malfunctioning

The brakes will cease working correctly if the MTB fluid becomes gel-like and thicker.

In addition, slamming on the breaks will accidentally trigger an emergency brake activation randomly on a bicycle.

What Brake Fluid Do I Need For My Mountain Bike?

There are currently two distinct kinds of brake fluid that you can use in mountain bike brakes: mineral oil and DOT fluid.

It doesn’t matter which one you choose; you should only use the oil brake fluid for which your brake was engineered.

Your brakes’ performance will suffer if you use improper fluid in them. There will be a variety of problems, including but not limited to the following:

  • Modifications to the ‘feel’ and ‘characteristics’ of brakes; for example, the brake may become less sensitive and clunky.
  • Internal seals corroded or swollen, causing leakage.
  • Incompatibility of DOT fluid and mineral oil causes dispersion and accumulation of braking fluid inside brake lines.

#1. DOT Fluid

With its widespread application in the automotive sector, DOT fluid is now the type of brake fluid that may be considered the one that is used the most frequently.

Except for DOT 5, all DOT fluids have a poly-glycol basis.

Glycol-based fluids are made up of many different constituents, with the final result including approximately ten different chemicals.

There are four main parts to these substances:

  • Lubricant (20-40%), such as polypropylene or polythene, keeps components moving quickly.
  • The viscosity and boiling point of the fluid is determined by the solvent diluent, which is often glycol ether.
  • A modifier-coupler, sometimes known as a coupler, modifies how exposed rubber portions expand.
  • Inhibitors, which inhibit corrosion and oxidation.

Therefore, the term “DOT brake fluid” comes from the product’s requirement to adhere to strict criteria and guidelines established by the Society of Automotive Engineers and the Department of Transportation (DOT).

These guidelines also stipulate the required boiling temperatures that fluid makers must adhere to ensure that brake fluid performs at various temperatures.

One remarkable thing is that the advantages exceed the drawbacks in this case.

Changing your brake fluid yearly to combat the reduction in boiling point prevents water from accumulating in your brakes. 

In addition, given that it is federally controlled, brake manufacturers may focus on manufacturing brakes rather than creating brake fluid, confident knowing that the DOT fluid they are meant to work with is of consistently excellent quality.

#2. Mineral Oil

When it comes to Mineral Oil brake fluid, no standard or regulatory organization governs the many components that contribute to its makeup, so getting technical knowledge about them might be challenging.

Mineral Oil brake fluid is expensive. As it’s unique, there’s no competition, and the guarantee says to use it, they can charge whatever they want. 

Mineral Oil isn’t regulated like DOT brake fluid.

Professionals consider this as an upper hand since they do not have to rely on someone else’s testing standards and can guarantee outcomes.


It is common knowledge that MTB brake fluid is oily and devoid of water, implying that it doesn’t freeze but instead gets denser and ineffectual in the braking system.

However, a few minutes of driving around should be enough to get it back in working order if you’ve had an issue with your motorbike brake system.

Josh Matthews

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