Road and MTB Sprockets Compatibility Overview

Points to Check When Verifying Compatibility Between Road and MTB Sprockets

Among bicycle components, sprockets are generally considered to have relatively loose compatibility. As a result, some component manufacturers, such as Shimano, may use road and MTB sprockets as shared parts.

However, while there may be compatibility between some road and MTB sprockets, it is important to understand that they are not always fully interchangeable.

“Officially Compatible” Sprockets

When checking the compatibility of road and MTB sprockets, the first step is to refer to the official compatibility charts for the shifting components. For Shimano, you can check their “Specifications and Technical Information Site”¹, and for SRAM, you can refer to the “Compatibility Map”².

Both Shimano and SRAM distinguish compatibility between road and MTB, but some sprockets are shared. Therefore, it is best to search for a compatible shared sprocket based on your components.

However, shared sprockets between road and MTB are limited in number, and there is a high chance they may not have the desired gear configuration. In such cases, you will need to use a sprocket that is outside of the official compatibility.

“Non-Officially Compatible” Sprockets

Even with combinations of sprockets and components that are not officially compatible, it is possible to use them if the number of gears is the same. However, please note that the following explanation pertains to “non-officially compatible” combinations, so it is important to proceed at your own risk.

Bicycle sprockets, when they have the same number of gears, often have only minimal differences (a few millimeters) in gear spacing and thickness, even between different manufacturers. These differences can often be absorbed through shifting adjustments, although there may be a reduction in shifting performance.

In many cases where road and MTB sprockets and components are combined, “non-officially compatible” sprockets will be used. In such cases, you should check the following three points:

1. Freehub Compatibility -> Can it be mounted?
2. Gear Capacity -> Will shifting be possible?
3. Shifting Technology -> Can the shifting performance meet the manufacturer’s expectations?

Freehub Compatibility

The first thing to check is the compatibility between the sprocket and the freehub.

For example, Shimano’s 12-speed road sprockets use the “HG Spline L2” standard, while MTB 12-speed sprockets use the “Micro Spline” standard, which are completely incompatible with each other. Therefore, if you wish to use them, you will need to replace either the freehub or the entire wheel.

If you can clear this compatibility issue, you will be able to mount the sprocket on your current bike.

For more information about freehub and sprocket compatibility, please refer to the following article:

Gear Capacity Compatibility

The biggest hurdle when considering the compatibility between road and MTB sprockets is “gear capacity compatibility.”

Bicycle shifting components not only have “number of gears” but also differences in “rear derailleur capacity.”

“Gear capacity compatibility” refers to the “minimum and maximum teeth counts on the sprocket,” “top minimum and maximum teeth counts,” and “total gear count of the drivetrain.” In simple terms, it is the “number of gears the rear derailleur can handle on a sprocket.”

For example, even with the same 11-speed, Shimano’s road-oriented rear derailleur RD-R7000-GS has a maximum top cog of 11T and a maximum low cog of 34T. Therefore, MTB 11-speed sprockets like the “CS-M9001 (10-45T, 10-51T)” or “CS-M5100-11 (11-51T, 11-42T)” cannot be used.

On the other hand, Shimano’s MTB rear derailleur RD-M5120-SGS has a minimum low cog of 42T, so it cannot use road sprockets.

Therefore, even if the sprocket can be mounted, if the derailleur does not support the gear count, shifting will either not be possible or will result in severely reduced shifting performance.

Compatibility of Shifting Technology

Each component manufacturer has its own “shifting technology.” For Shimano, this includes “HYPERGLIDE” and “LINKGLIDE,” while for SRAM, there are “X-SYNC” and “PowerGlide” technologies.

Sprockets are one of the components that make up these shifting technologies, and the standard is to build a shifting system with parts that use the same technology. Therefore, even within Shimano’s sprockets, there is no official compatibility between the “HYPERGLIDE” and “LINKGLIDE” sprockets.

However, when combining parts with different technologies, it is not always the case that shifting won’t work. In fact, there have been many reports on social media where shifting works even when combining Shimano’s MTB components (HYPERGLIDE) with SRAM’s MTB sprockets (PowerGlide).

Similarly, if the freehub and rear derailleur capacities are compatible, it is possible to use MTB sprockets with road components, although this is not officially supported by the manufacturers.

Of course, since this is an “officially unsupported” combination, shifting performance may be compromised. However, if you can accept the potential decrease in shifting performance and are willing to use “non-official” combinations, it is possible to mix and match road and MTB sprockets without worrying about compatibility.