Shimano Biopace-SG chainring 52 teeth 130 mm 7/8 speed

Shimano Biopace-SG 52T chainring 130 mm BCD – Classic road bike chainring for 7 to 8-speed drivetrains

The Shimano Biopace-SG 52-tooth chainring is an iconic component that played an important role in the history of road cycling. Designed by Shimano, it features the distinctive Biopace profile, created to provide a smoother pedaling motion and improved riding comfort. Today, it remains highly sought after by vintage bicycle enthusiasts, collectors, and cyclists restoring classic road bikes with original Shimano components.

This model is an outer chainring made from aluminum, designed for 7 to 8-speed drivetrains. With its 130 mm bolt circle diameter (BCD) and 52 teeth, it is compatible with many Shimano cranksets from the Biopace era.

Shimano Biopace-SG chainring specifications

Key features include:

• Brand: Shimano

• Model: Biopace-SG

• Teeth: 52T

• Position: Outer chainring

• Bolt Circle Diameter (BCD): 130 mm

• Compatible Drivetrains: 7 to 8-speed

• Material: Aluminum

• Color: Gray

• Weight: 85 grams

• Condition: New, without original packaging

Smooth pedaling with Shimano Biopace technology

Shimano's Biopace system features a slightly oval chainring profile designed to reduce dead spots during the pedal stroke. The goal was to create a smoother and more efficient pedaling experience, especially during long rides. This innovative design was widely used on road and touring bicycles throughout the 1980s and early 1990s.

The Shimano Biopace-SG 52T chainring remains an excellent choice for preserving the authenticity of a vintage bicycle or replacing a worn original component.

Compatibility with Shimano cranksets

Featuring a 130 mm BCD, this chainring fits many Shimano cranksets that use the same bolt pattern. It is intended for use as the outer chainring on a double chainring crankset.

The tooth profile is optimized for 7 and 8-speed chains, ensuring smooth shifting when paired with a compatible drivetrain.

Before purchasing, it is recommended to verify:

• Your crankset's 130 mm BCD

• Compatibility with a 7 or 8-speed drivetrain

• The desired tooth count for your preferred gear ratio

Lightweight and durable aluminum construction

Manufactured from high-quality aluminum, the Shimano Biopace-SG chainring offers an excellent balance of durability and low weight. At only 85 grams, it helps keep your bike lightweight while providing long-lasting performance under normal riding conditions.

Its classic gray finish perfectly matches Shimano groupsets from the same era, making it an ideal component for vintage bicycle restorations.

Why choose the Shimano Biopace-SG 52T chainring ?

The 52-tooth gearing is ideal for road cycling, offering an efficient gear ratio for maintaining higher speeds on flat terrain while delivering smooth pedaling performance.

This chainring is particularly well suited for:

• Vintage road bike restorations

• Replacing a worn Biopace chainring

• Classic Shimano component collections

• Period-correct retro bicycle builds

• Cycling enthusiasts who appreciate original Shimano technology

Its unique Biopace design makes it a desirable component among collectors and riders alike.

Product condition

This Shimano Biopace-SG chainring is offered new without original packaging. It has never been installed or used but is supplied without its factory packaging.

It is an excellent opportunity to replace a hard-to-find original chainring or complete the restoration of a classic Shimano-equipped bicycle.

Key benefits

• Genuine Shimano original component

• Classic Biopace oval chainring design

• Lightweight and durable aluminum construction

• Only 85 grams

• Standard 130 mm BCD

• Compatible with 7 and 8-speed drivetrains

• Perfect for vintage road bike restorations

• New condition without original packaging

Conclusion

The Shimano Biopace-SG 52T 130 mm BCD chainring is an outstanding choice for vintage cycling enthusiasts, collectors, and anyone restoring a classic Shimano-equipped road bike. Lightweight, durable, and designed for 7 to 8-speed drivetrains, it preserves the performance and character that made Shimano Biopace components so distinctive.

Whether you're restoring a classic road bike, replacing a worn original chainring, or simply looking to experience Shimano's innovative Biopace technology, this new old stock (NOS) chainring without original packaging is a rare and highly desirable component for any vintage cycling project.