Shimano road disc brake component compatibility summary

Disc Brake Component Combinations

Unlike rim brakes, road bike disc brake components come in a few different configurations.

The main distinction is between hydraulic and mechanical (cable-actuated) systems, and this determines the compatible combinations of STI levers and brake calipers.

For hydraulic systems, you need a dedicated set of components: hydraulic STI levers, hydraulic calipers, and hydraulic hoses.

In contrast, with mechanical disc brakes, you can reuse STI levers and cables from a rim brake setup. The only component that needs to be disc-specific is the mechanical disc caliper.

In addition to brake setup, you’ll also need to consider shifting type — mechanical or electronic (Di2) — when selecting components.

Keep in mind that the latest DURA-ACE R9200 and ULTEGRA R8100 series are Di2-only groupsets, meaning there are no mechanical shifting STI levers available in those lineups.

Shimano Hydraulic Disc Brake Components

Shimano offers hydraulic disc brake components for road bikes in four grades: DURA-ACE, ULTEGRA, 105, and TIAGRA.

Shimano Hydraulic Disc Brake STI Levers for Road Bikes

The current Shimano lineup for hydraulic disc brake STI levers includes models from TIAGRA and above, meaning they are only compatible with 2x10 or higher component setups.

While the brake mechanism is hydraulic, note that the shift mechanism may be either Di2 (electronic) or mechanical, which differentiates the products.

Previously, only ULTEGRA and higher components had Di2, but in June 2022, Shimano released the R7170 series of the latest 105 components compatible with Di2.

For STI levers with hydraulic brakes x Di2, the model numbers end in “70”, while for hydraulic brakes x mechanical shifting, the model numbers end in “20”.

Note: The numbers in parentheses indicate small hand models.

Shimano Hydraulic Disc Brake Calipers for Road Bikes

Shimano’s hydraulic disc brake calipers for road bikes are compatible with components from TIAGRA and above when paired with STI levers. Additionally, Shimano’s road bike components are also compatible with the GRX brake calipers.

Shimano follows a “BR-RXXXX” model numbering system for their road bike brakes, with the last two digits of the model number being “70” for hydraulic disc brake calipers. However, for the GRX gravel components, which are only available with hydraulic brake models, this rule does not apply.

Also, according to Shimano’s official compatibility chart, it’s important to note that 12-speed hydraulic brake STI levers are not compatible with 11-speed hydraulic brake calipers. On the other hand, 11-speed or 10-speed hydraulic brake STI levers can be used with 12-speed hydraulic brake calipers.

Shimano Mechanical Disc Brake Components

Shimano Mechanical Disc Brake STI Levers for Road Bikes

For mechanical disc brakes, STI levers designed for rim brakes can also be used. Although it seems like there might be a difference in the amount of cable pull between disc brake and rim brake calipers, Shimano ensures compatibility across these components.

As a result, the STI levers that can be used are “all STI levers for current road models except the ‘hydraulic versions’,” meaning there are many options ranging from 2x8 to 2x12 speeds.

Even for mechanical brake STI levers, DURA-ACE and ULTEGRA models come in two variants, depending on whether the shifting is Di2 (electronic) or mechanical, so be sure to check for this.

For “Mechanical Brake x Di2” STI levers, the last two digits of the model number are “50,” while for “Mechanical Brake x Mechanical Shifting” STI levers, the last two digits are “00” (with some exceptions, such as front triple systems).

Shimano Mechanical Disc Brake Calipers for Road Bikes

While Shimano’s primary focus for disc brakes is on hydraulic models, the selection for mechanical disc brake calipers is significantly smaller compared to STI levers.

Currently, there are only four available options in the lineup for mechanical disc brakes. If you’re using mechanical disc brakes, you may want to consider exploring brake calipers from other manufacturers as well.

Shimano Disc Brake Rotors

A disc rotor is essential for disc brakes.

Shimano offers disc brake rotors for both road and MTB bikes, with various grades. The differences lie in weight, cooling capabilities, and size options. The grades range from high-end DURA-ACE to non-graded options, making it easier to choose the right one for your needs.

Even MTB-grade rotors in 140mm and 160mm sizes can be used on road bikes, but MTB-specific sizes like 180mm and 203mm are generally not compatible with road bikes.

When choosing a disc rotor, it’s important to ensure compatibility with the brake caliper’s pad type (resin or metal), so make sure to select a rotor that matches the pad material.