PCD compatibility chart for cranks and chainrings

What is PCD?

When replacing a chainring, the PCD must match

The chainring, a part of the crankset, is a consumable component that needs replacement after long-term use. At that time, the value used to determine compatibility with the crank is the PCD (Pitch Circle Diameter).

When choosing a chainring, make sure to match the following:

• Number of arms
• PCD

However, even if both the arm count and PCD match, certain chainring-to-sprocket combinations may not be compatible due to derailleur capacity. Always double-check compatibility.

What are Shimano's SS and GS rear derailleurs?

The "SS" and "GS" indications on Shimano's rear derailleur model numbers. We will explain the difference between them, how to distinguish between them, and which one to choose, including compatibility.

PCD can be calculated from the distance between two bolt holes

Even if you don’t know the exact crank model you have, you can determine the PCD by measuring the distance between the bolts securing the chainring.

Arm Type and PCD

Even if the PCD is the same, there is no compatibility between 4-arm and 5-arm cranks if the number of bolt holes differs.

For the currently mainstream 4-arm cranks, the common PCD types are:

• PCD: Φ64mm
• PCD: Φ104mm
• PCD: Φ110mm

In contrast, for the previously mainstream 5-arm cranks, the common PCD types are:

• PCD: Φ74mm
• PCD: Φ104mm
• PCD: Φ110mm
• PCD: Φ130mm

Chainring PCD of Shimano Road Cranksets

Let’s take a look at the PCD specifications for Shimano cranksets.

For Shimano’s 4-arm cranks, most models use a 110 PCD for both inner and outer chainrings.

The only exception in Shimano’s 4-arm lineup is the FC-RX600-11 with a 46/30T configuration. The outer chainring (46T) uses a 110 PCD, while the inner (30T) uses a much smaller 80 PCD.

Take note that older 5-arm cranks like FC-6700 or FC-5700 (2–3 generations old) have varying PCDs depending on the chainring size. While compact cranks use a 110 PCD, semi-compact and larger sizes use a 130 PCD.

This means you cannot fit a semi-compact chainring onto a compact crank arm.

Be Cautious When Replacing Chainrings on Shimano 4-Arm Cranks

Up to the 5-arm era, Shimano front cranks had equally spaced bolt holes, which made them relatively compatible with third-party chainrings. However, with 4-arm cranks, the spacing is no longer uniform—the vertical distance is longer than the horizontal—which means only compatible chainrings will fit.

All current and previous-generation Shimano road cranks use 4-arm designs, so when replacing chainrings for these models, you must check not only the number of arms and the PCD, but also whether the chainring is specifically compatible with Shimano’s 4-arm crank structure.

Even between different Shimano 4-arm cranks with the same PCD, there may be slight differences in mounting shapes depending on the generation or model. Always check compatibility carefully.

Leading third-party chainring brands like ROTOR provide detailed compatibility charts on their websites. Make sure to consult these in addition to checking the PCD.

Chainring PCD of Shimano MTB Cranksets

For Shimano MTB cranksets, the smaller chainring sizes in multi-chainring setups result in different PCDs for inner and outer rings.

In addition, for single-chainring setups (now mainstream in MTB), some cranksets use a “direct mount” system instead of traditional bolt patterns.

Note that older MTB models may use different PCDs than those listed above. It’s best to consult a professional shop when replacing chainrings.

Compatibility of Shimano Direct Mount Chainrings

In high-end MTB groupsets, the trend is moving toward front single drivetrains. Consequently, Shimano MTB cranks now mainly use direct mount systems.

The following four Shimano cranksets use the direct mount system:

1. FC-M9100-1
2. FC-M8100-1
3. FC-M7100-1
4. FC-M6100-1

Shimano’s direct mount chainrings require special tools and Hollowtech II tools for installation.

Looking beyond Shimano, there are several incompatible direct mount standards, including:

1. Shimano Direct Mount
2. SRAM Direct Mount
3. RACEFACE Cinch

Each has its own compatibility requirements.

Frequently Asked Questions About Cranks, Chainrings, and PCD