Can I Use An MTB Crankset On A Road Bike?

You might already have car brake fluid which could lead you to consider using it for your mountain bike. The brake system on your mountain bike relies on fluid to work properly, and your car’s brakes work similarly. So can I use car brake fluid on my mountain bike, and is it safe?

Car brake fluid is safe to use on a mountain bike. There are only a few differences between brake fluid used for cars and mountain bikes. Any brake fluid’s quality can impact the brakes’ performance over time. Car brake fluid is more standardized, which makes it better quality.

Knowing the different types of brake fluid, you can use on your mountain bike will help you better understand why car brake fluid is safe for your mountain bike. Overall, it comes down to the quality of the brake fluid you use and whether or not you use the correct grading for your brake system.

Is It Okay To Use Car Brake Fluid On My MTB?

To have a safe trip, brakes that perform well are a must. Instead of buying more equipment for your mountain bike, you may want to use the car brake fluid that you already have. Two types of brake fluid are usually used on mountain bicycles. They are mineral oil and DOT fluid.

Mineral Fluid For My MTB

Mineral oil is specifically for bicycle brakes, not car brakes, whereas DOT fluid can be used on your bicycle or car. However, you should contact the bicycle manufacturer before deciding which brake fluid to use.

Mineral oil may be advertised as suitable brake fluid for mountain bikes, but it’s not regulated, whereas car brake fluid is regulated. This means that the quality of car brake fluid is more ensured. This is important because using bad-quality brake fluid could lead to brake failure.

DOT Fluid For A MTB

DOT fluid is a general brake fluid used in the automotive industry. It is regulated, which means it’s more likely to be high quality. The only kind of car brake fluid that can’t be used on bicycle brakes is DOT 5. This is because DOT 5 contains silicone, which makes seals swell and damages your bicycle’s brakes.

Most mountain bike brands use DOT 4 or DOT 5.1 because they have a high boiling point. This is key because your brakes will fail if brake fluid boils. Even though car brake fluid lets in water, it does not gather in one place but spreads evenly, preventing the water from boiling and maintaining peak performance.

Altogether, DOT fluid is made for cars and can be used on bicycles, but getting advice from the bicycle manufacturer will ensure you make the right decision.

Car Brake Fluid For A MTB

It may be possible that your car uses brake fluid with the same grading as your mountain bike. What’s more, some mountain bikes work better when car brake fluid is used rather than mineral oil that is made for mountain bikes.

Most cars use DOT 4 as a suitable brake fluid. DOT 4 should also be compatible with most mountain bike brakes. This is useful because you won’t need to buy a separate brake fluid for your mountain bike. Still, checking that DOT 4 is compatible is a good idea.

Some mountain bike brake systems, such as Hope Tec3, are incompatible with mineral oils sold for mountain bikes. These brakes work better with brake fluid used for cars such as DOT 5.1 or DOT 4. In this case, car brake fluid is the safest option.

Is Car Brake Fluid Safe For A MTB?

It’s a good idea to check which type of fluid your bicycle’s brake system is supposed to use. Some brands may require a specific type of mineral oil instead of car brake fluid.

Whether or not you can use car brake fluid on your mountain bike will depend on the make, as they have different brake systems. Brands like Shimano, Magura, and Campagnolo require a specific type of mineral oil, and using car brake fluid could damage the brake system.

Even though car brake fluid keeps brakes cool and prevents corrosion, the quality deteriorates over time. The longer you have car brake fluid, the more moisture it lets in when you use it. This decreases the boiling point, meaning there is reduced stopping power, or your brakes may fail altogether. If you use car brake fluid for your bike, make sure it is new.

Car brake fluid is not dangerous for your mountain bike but is corrosive and can damage the paintwork. You can prevent this by wearing gloves and immediately wiping off any excess fluid that runs onto the bike.

Considerations For Car Brake Fluid And A MTB

Knowing your bike before using car brake fluid is ideal, as there may be certain specifications. Find out more about your bike’s requirements before using car brake fluid on the brakes. A few things to consider would be

  • Can you use mineral oil if the bike is under warranty? Yes, you can, and it may be recommended depending on your bike’s make. Some mountain bikes may have warranties to get cash back if something happens to your bike.
  • What kind of brake fluid is required under guarantee? This guarantee may specify that you need to use a specific kind of brake fluid made for mountain bikes and not cars, such as mineral oil.
  • Can you use car brake fluid in all environments? Car brake fluid is safe for mountain bikes because it has a high boiling point. If you live in hotter conditions, your brake fluid may be more likely to reach a boiling point than in a cold area. However, you can choose a car brake fluid with a higher boiling point, such as DOT 4, which has a higher boiling point than DOT 3.
  • Can you mix car brake fluid? Mixing two or more different kinds of brake fluids and using them on your mountain bike could ruin your braking system. This is because the boiling point will sink to the lowest level of performance. DOT 4 has a higher boiling point, but if you mix it with DOT 3, the boiling point will sink to that level.

Having these considerations in mind makes it possible to use car brake fluid on your mountain bike without causing damage to the brake system. It is better to gather all the information before choosing which brake fluid to use.


Car brake fluid is safe to use on your mountain bike. However, like anything, different brands of car brake fluid are of higher quality. Using a lesser quality brake fluid may cause damage. Overall, it’s better to contact the manufacturer to double-check if they prefer car brake fluid or mineral oil.


Similar Posts