What Brake Fluid Do I Need For My Mountain Bike – Detailed Guide

You must have discovered a lot about the types of oils and how the brake system works. So that’s what I am not going to share here making you bored.

I will take you through this journey by explaining which brake fluid you need for a mountain bike and why is it suitable, telling you some basic properties so you better understand the nature of oils and make the best decision for your bike’s brake system. Let’s move ahead and explore.

What Brake Fluid Do I Need For My Mountain Bike

What Brake Fluid Do I Need For My Mountain Bike

Before discussing about right brake fluid for your mountain bike, let me tell you about the types of brake fluids for mountain bikes.

Types of Brake Fluid for MTBs

1. Mineral oil

2. DOT

Advantages and disadvantages of Mineral Oil and DOT for MTB Brakes

Boiling and Freezing Temperatures

Before we jump into the decision I would like to share that each type of brake fluid has its own properties, like boiling and freezing temperatures. the higher the freezing and boiling point the better the oil is and thus it will be more suitable for mountain bikes. Also, if you know about mechanics, then you would probably know that for brake fluids you can also use car fluids as well. But in some cases only.

If you ask me then I would say that the best fluid for mountain bikes is DOT 3, 4, and 5. If you are wondering why there are series then let me inform you here that these numbers are given according to their boiling and freezing points. For Example, number 3 has the lowest freezing and billing point while number 5 has the most high boiling point. So if you ask me, let me tell you that number three won’t be suitable for mountain bikes.

If I talk about mineral oil then let me tell you here that their freezing and boiling points are a little lower as compared to the DOT. as you need a higher boiling and freezing point n the mountains, thus it won’t be much suitable for your bike. However, they are corrosion free and have a longer life span.

Weather Influence

The DOT is best for mountain bikes because they perform best even in rainy weather. I mean they are hygroscopic and thus water doesn’t get mixed with them. The brakes work efficiently even in harsh weather conditions and you can ride the bike stress-free. However, the mineral oil gets mixed with water and harms the braking system of the bike.


DOT oils are way too dangerous to work with. If you accidentally spill it, this might burn your skin. So before you start working with DOT brake fluids it is better that you wear mechanic gloves for safety. The mineral oils on the other hand are safer and you can work with them even if you forget to wear gloves.

Take Manufacturer’s Suggestion about Right MTB Brake Oil

Although the DOT has many advantages and is best regarding its properties, there is still a little twist and that is the choice can’t be yours totally. Every bike does not accept the DOT while others do not accept the mineral oil.

So you have to ask the manufacturer which bike oil will be the best for your bike type. If you go against the manufacturer’s guidance then the corrosion might start developing inside which can damage the whole brake system late.

Mixing DOT 3 and 4?

Some people ask if they can mix the DOT 4 and 3? well, the answer is no. DOT 3 has a considerably low boiling and freezing point while DOT 4 has a high boiling and freezing point. So when they mix up they ruin their properties and damage the brake system of your mountain bike.

Concluding MTB Brake Fluid Guide

When you are selecting a mountain bike brake fluid you should first as the manufacturer which fluid will suit your bike. If somehow the manufacturer isn’t available then you should read the manual. You should never add the brake fluid without knowledge, as it can damage the brakes.

When it comes to which brake oil should be used in mountain bikes we have seen that performance wise the DOT gives the best but for durability and reliability wise mineral oil is great, so there is no specific answer to this.

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