Types of brake fluid explained
Everyone loves riding really quick but we all know that stopping is just as important. This is the part where the brakes come into the picture. Brakes are one of the most important safety systems on a bike or car. Obviously, they help to stop the car quickly and avoid accidents. Modern motorcycles and cars use hydraulic brakes in the front and rear. These types of brakes use a special kind of oil called brake fluid which uses hydraulic pressure to transfer pressure from the lever on the handlebar to the calipers on the rotors. There are currently 4 kinds of brake fluid, namely, DOT 3, DOT 4, DOT 5 and DOT 5.1. You might be wondering why there’s so many different types of brake fluid and what works best for your bike. We’ll dive into that question in this blog.
For brake fluid to be useful it needs to have a few properties like non compressible so it can transfer pressure effectively, It needs to have low viscosity to be compatible with modern ABS units. A fluid with a low viscosity flows readily because its molecular structure produces less friction when in motion. It’s got to be corrosion resistant while also having a high boiling point. And lastly it needs to offer a certain amount of lubrication so that the oil seals function smoothly. That’s quite a few responsibilities for a fluid. This links back to why there’s so many kinds of fluid in the first place, some fluids do a better job than others.
What’s what?
To put it simply, DOT 3, 4, 5.1 are glycol based and can be mixed with each other. However, DOT 5 is a silicon based oil which can not be mixed with the others. Each type of fluid has its own characteristics and is used for different applications. So what’s the chemistry behind this? DOT 3,4 and 5.1 are hygroscopic which means they draw moisture from the environment which leads to its decomposition. However, DOT 5 is glycol based and so it is hydrophobic which effectively means it repels moisture making it longer lasting.
What’s the best brake fluid?
Based on our arguments you might be thinking that DOT 5 sounds ideal. However, it has its fair share of shortcomings like its compressibility, price and viscosity make it unfit for modern motorcycles. Harley Davidson was using this magical brake oil until a few years back before the ABS norm. DOT 5 was prone to flocculation which would essentially clog the system. ABS pumps could simply not work with this fluid.
So what’s the real difference between the three? And what’s best? Boiling point is the primary difference between the 3. The higher the boiling point the more heat and harsher braking the bike can take. The specific kind of fluid your bike needs is printed on the top of your master cylinder cap and is also mentioned in the service manual.
DOT 3 has the lowest boiling point and has pretty much been defunct by the automobile industry. DOT 4 brake fluid has a slightly higher boiling point and is generally what most motorcycles use. DOT 5.1 has the highest boiling point. Racing brake fluid is essentially a superior DOT 5.1 with an even higher boiling point. Our expert riders suggest that motorex brake fluid is far by the best option out there. It offers best value for money and provides great heat resistance.
Does brake fluid expire?
Since most commonly used brake fluids are hydrophilic, they do expire. With old moisture riddled fluid, the boiling point drastically lowers which results your brake lever becoming spongy and thereby harder to brake effectively. And that’s why manufacturers recommend you bleed your brakes regularly.
Our expert riders suggest that once every 2 years is sufficient. If you’re a track rider who is heavy on the brake, you might want to consider upgrading your brake fluid to the DOT 5.1 to get the most out of your bike.
Signs of bad brake fluid
● Spongy brake lever
● Old brake pads (More fluid required to push the pads since they’ve become thinner)
● ABS warning light
Important aspects to keep in mind when changing brake fluid
Since DOT 3, 4,5.1 brake fluids are glycol based, so if it spills on painted, plastics or rubber surfaces of your bike, it will most definitely damage it if not dealt with. Hence it is important that you wipe down any spillage immediately with a damp cloth.
It’s important to note that brake fluid is extremely corrosive as well and so our expert riders suggest that you apply a bit of grease to the reservoir cover and screws to make sure to prevent corrosion which in turn will make opening and closing of the reservoir cover easier.
It’s important that you bleed all the air bubbles out of the system after topping it up since any trapped air would make the fluid compressible and thereby negatively impact braking performance.
How to buy Motorcycle Brake Fluid on Custom Elements?
If you’re looking to service your brake fluid or up your braking game, it might be a good idea to shop for brake fluid and other essentials at a reputed online marketplace like Custom Elements. Head over to our brake fluid page where you can use a couple of search filters to navigate and narrow your search. Once you find the right tyre, proceed to check out. Avail of discounts and offers if you use Snapmint Easy EMI or Simpl.
Disclaimer: The views & opinions put forward in this blog are purely from a personal perspective of the author & do not represent the opinions of any entity whatsoever.
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