SM-RT800 Disc Brakes vs. SM-RT86: Key Differences Every Cyclist Should Know

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When selecting the right disc brake for your road bike, the choice between Shimano’s SM-RT800 [paid link] and SM-RT86 models is crucial for achieving the best performance. Both models are highly regarded for their quality and efficiency, but they are designed with slightly different applications and features. This article breaks down the key differences between the SM-RT800 [paid link] and the SM-RT86 to help you make an informed decision.

Rotor Design and Material Composition

One of the most significant differences between the SM-RT800 [paid link] and SM-RT86 lies in their rotor design and material composition.

  • SM-RT800: This rotor uses Shimano’s proprietary “Centre-Lock” system and features a 3-layer construction, combining a stainless steel braking surface with an aluminum core. The construction is designed to reduce weight while maintaining excellent thermal management.
  • SM-RT86: Also featuring the Centre-Lock system, the SM-RT86 rotor has a more advanced heat-resistant design with a dual-layered steel construction. This rotor has a thicker stainless steel outer surface compared to the RT800, which helps to dissipate heat more effectively during extended braking sessions.

Performance and Heat Dissipation

Both the SM-RT800 and SM-RT86 offer superb braking performance, but their heat management systems differ.

  • SM-RT800: The aluminum core of the RT800 offers better weight savings, making it a good option for riders looking for a lightweight rotor without sacrificing performance. However, it is not as optimized for extended heat dissipation as the SM-RT86. Riders who engage in long, sustained braking, such as during downhill rides, may notice a slight decrease in braking performance due to heat buildup on the RT800.
  • SM-RT86: The SM-RT86 rotor is specifically designed for better heat dissipation. With its dual-layer steel construction and thicker braking surface, it performs exceptionally well in extreme conditions. The increased thickness allows the rotor to better handle prolonged braking without warping or losing effectiveness. This makes the SM-RT86 a superior option for aggressive riders or those riding in hot climates.

Weight Comparison

Weight is always a critical factor when it comes to road bike components, especially if you’re aiming to improve performance.

  • SM-RT800: Weighs approximately 135g for the 160mm version. The lighter weight is a result of its aluminum core, making it a better choice for weight-conscious riders who don’t necessarily need the maximum thermal management.
  • SM-RT86: Weighs about 145g for the 160mm version. While slightly heavier than the RT800, this rotor’s additional mass contributes to its superior heat management and durability, making it worth the extra grams for riders focused on performance and reliability in demanding conditions.

Compatibility and Use Case

Both the SM-RT800 and SM-RT86 rotors are compatible with Shimano’s high-performance disc brake systems, but their intended use cases may differ.

  • SM-RT800: Ideal for everyday road cyclists who engage in standard riding conditions. It is a versatile rotor that works well on both wet and dry roads, providing reliable braking performance in varied environments.
  • SM-RT86: Better suited for competitive cyclists or those who engage in extreme cycling conditions such as mountain descents, trail riding, or endurance cycling. The heat management and performance under heavy braking conditions make the SM-RT86 rotor the top choice for riders seeking the highest level [paid link] of braking efficiency under stress.

Pricing and Value

Pricing is another aspect that might influence your decision.

  • SM-RT800: Typically, the RT800 comes at a lower price point than the RT86. It offers a good balance between performance and affordability, making it a great choice for casual cyclists or riders who do not frequently push their braking systems to their limits.
  • SM-RT86: The RT86 is more premium-priced due to its enhanced thermal performance and thicker construction. Cyclists who prioritize durability and consistent performance under heavy braking will find the cost justified.

Summary: Which One Should You Choose?

When deciding between the SM-RT800 and SM-RT86, the primary factors to consider are the type of riding you do and your performance needs:

  • Choose the SM-RT800 if you’re a road cyclist who seeks a lightweight, reliable rotor for everyday use, with good performance in both wet and dry conditions.
  • Choose the SM-RT86 if you require a rotor that can handle extreme conditions, long descents, or continuous braking without compromising performance. Its superior heat dissipation makes it a must-have for serious cyclists pushing their gear to the limit.

Ultimately, both rotors are high-quality, but understanding your riding style and needs will help you select the best option for your bike.