Shimano’s GRX series is a popular choice among gravel and adventure cyclists. It is specifically designed to meet the demands of off-road cycling with its rugged construction, reliable performance, and versatile features. When it comes to choosing the right brake for your GRX groupset, you have two options: the GRX 400 and the GRX 800. In this article, we will compare the key differences between these two brake models and help you choose the one that best fits your needs.

Key Differences between GRX 400 and 800 Brakes

The GRX 400 and 800 brakes share many similarities, but there are some key differences that set them apart.

Brake Lever Design and Functionality

One of the most noticeable differences between the GRX 400 and 800 brakes is the design and functionality of their brake levers.

Lever Shape and Size

The GRX 800 brake levers have a slightly different shape than the GRX 400 levers. The 800 levers are slightly longer and have a more pronounced curve. This shape makes them easier to grip and provides better leverage when braking.

Reach Adjustability

The GRX 800 brake levers also offer reach adjustability, which means you can adjust the distance between the lever and the handlebar to fit your hand size and riding style. This feature is not available on the GRX 400 brake levers.

Dropper Post Lever Integration

Another feature that is unique to the GRX 800 brake levers is the integration of a dropper post lever. If you have a dropper seat post, you can use the same lever to control both the brakes and the seat post, which simplifies your cockpit and reduces clutter.

Brake Caliper Design and Features

While the brake lever design and functionality may not affect the braking performance directly, the design and features of the brake caliper do. Here are some key differences between the GRX 400 and 800 brake calipers.

Number of Pistons

The GRX 800 brake calipers have four pistons, while the GRX 400 calipers have two. This means that the GRX 800 brakes have more stopping power and can provide better modulation than the GRX 400 brakes.

Heat Dissipation

The GRX 800 brake calipers also have better heat dissipation than the GRX 400 calipers. This means that the GRX 800 brakes are less likely to overheat and fade during prolonged use.

Weight and Durability

The GRX 800 brake calipers are lighter and more durable than the GRX 400 calipers. This is due to the use of high-quality materials and a more advanced manufacturing process in the 800 model.

Pros and Cons of GRX 400 Brakes

Now that we have looked at the key differences between the GRX 400 and 800 brakes, let’s take a closer look at each model’s pros and cons.

Advantages

Lower Cost

The GRX 400 brakes are more affordable than the GRX 800 brakes, making them an attractive option for cyclists on a budget.

Good Stopping Power

While the GRX 400 brakes have two pistons instead of four, they still provide good stopping power and are suitable for most off-road cycling activities.

Compatible with Multiple Rotor Sizes

The GRX 400 brakes are compatible with multiple rotor sizes, which gives you more flexibility when choosing a wheelset for your bike.

Disadvantages

Less Adjustability

One of the biggest drawbacks of the GRX 400 brakes is the lack of adjustability. You cannot adjust the reach of the brake lever, which may be an issue for riders with smaller or larger hands.

Fewer Features

The GRX 400 brakes also have fewer features than the GRX 800 brakes. They do not have reach adjustability or dropper post lever integration, which may be a drawback for some riders.

Heavier Weight

The GRX 400 brake calipers are heavier than the GRX 800 calipers. This may not be a big issue for some riders, but for those looking to shave off some weight from their bike, this may be a concern.

Pros and Cons of GRX 800 Brakes

Let’s now take a closer look at the pros and cons of the GRX 800 brakes.

Advantages

More Adjustability

The GRX 800 brakes offer more adjustability than the GRX 400 brakes. You can adjust the reach of the brake lever and integrate a dropper post lever, which gives you more control over your bike’s cockpit.

Better Heat Dissipation

The GRX 800 brakes have better heat dissipation than the GRX 400 brakes. This is a big advantage when riding in hot weather or on long descents, as it reduces the risk of brake fade.

Lighter Weight

The GRX 800 brake calipers are lighter than the GRX 400 calipers, which makes them a good choice for riders who prioritize weight savings.

Disadvantages

Higher Cost

The biggest drawback of the GRX 800 brakes is their higher cost. They are more expensive than the GRX 400 brakes, which may be a deal-breaker for some riders.

Limited Compatibility with Rotor Sizes

The GRX 800 brakes are only compatible with 140mm and 160mm rotors, which may be a drawback if you prefer larger or smaller rotors.

Harder to Bleed

Some riders have reported that the GRX 800 brakes can be harder to bleed than the GRX 400 brakes. This may not be an issue if you have experience bleeding hydraulic brakes, but it can be a challenge for beginners.

Conclusion

So which GRX brake should you choose? It ultimately depends on your needs and budget. Here are some factors to consider when making your decision:

• If you are on a budget and don’t need a lot of adjustability or features, the GRX 400 brakes are a good choice.
• If you want more adjustability and better heat dissipation, or if you want to save weight, the GRX 800 brakes are worth the investment.
• If you ride in hot weather or on long descents, the GRX 800 brakes may be a better choice due to their better heat dissipation.
• If you have a dropper seat post and want to simplify your cockpit, the GRX 800 brakes are the only option.

Ultimately, both the GRX 400 and 800 brakes are great options for off-road cycling. Whichever brake you choose, make sure to properly install and maintain it for optimal performance and safety. Happy riding!