Overfast Ultralight Di2 Battery Holder for Colnago Y1RS

Hidden Performance. Engineered for the Details.

The 2026 Overfast Ultralight Di2 Battery Holder has been developed exclusively for the Colnago Y1RS, replacing the original battery mounting system with an ultra-lightweight assembly engineered for riders who believe every gram—and every detail—matters.

Weighing just 10g (±1g), the Overfast battery holder delivers an incredible 97g weight saving compared to the original 107g Colnago assembly. Combining a full carbon fibre battery cover with a 3D-printed carbon composite body, it provides a secure, rattle-free solution without compromising strength or reliability.

Complete with a premium black titanium mounting bolt, laser etched with the OVERFAST logo, it's the perfect finishing touch for the ultimate Y1RS build.

Key Features

• New for 2026

• Designed exclusively for the Colnago Y1RS

• Weighs just 10g (±1g)

• Saves approximately 97g over the original Colnago battery holder

• Full carbon fibre battery cover

• Advanced 3D-printed carbon composite body

• Black titanium mounting bolt with laser-etched OVERFAST logo

• Ultra-lightweight construction

• Secure, rattle-free battery retention

• Direct replacement for the original battery holder

• Available in Forged Carbon or 3K Carbon finishes

Advanced Carbon Construction

The 2026 version introduces an all-new construction, pairing a lightweight 3D-printed carbon composite body with a premium full carbon fibre cover.

Every element has been engineered to remove unnecessary weight while maintaining exceptional rigidity and long-term durability. The result is a beautifully finished component that complements one of the world's most advanced road bikes.

Lightweight Without Compromise

Removing almost 100 grams from a hidden component is only worthwhile if reliability remains uncompromised.

The Overfast battery holder has been engineered with generous strength reserves and extensively durability tested, including more than 2,000 drop tests from 1 metre with a Di2 battery installed. Its rigid carbon composite construction also resists bending under substantial load, ensuring secure battery retention in real-world riding.

It's designed to be exceptionally light—but built with complete confidence.

Secure Fit. Zero Rattle.

The Overfast battery holder has been designed specifically around the Colnago Y1RS to provide a precise, secure fit within the downtube.

Once installed, the Di2 battery is held firmly in place, eliminating unwanted movement and preventing rattles, while maintaining easy access for servicing when required.

Simple Installation

Installation couldn't be easier.

Simply position the supplied titanium mounting bolt to the indicated reference mark, tighten into place and the battery holder is ready to ride. No specialist modifications or complicated setup are required.

Technical Specifications

• Compatibility: Colnago Y1RS

• Drivetrain: Shimano Di2

• Weight: 10g (±1g)

• Original Colnago Assembly: 107g

• Weight Saving: Approximately +80g

• Body Material: 3D-Printed Carbon Composite

• Cover Material: Full Carbon Fibre

• Mounting Bolt: Black Titanium with laser-etched OVERFAST logo

• Finish Options:

  • Forged Carbon

  • 3K Carbon

Why We Stock It

This is exactly the kind of product that defines Overfast. Instead of accepting the original design, they completely re-engineered one of the heaviest hidden components on the Colnago Y1RS, reducing its weight by over 80+ grams while improving fit, eliminating rattles and maintaining exceptional strength.

For riders building an uncompromising Y1RS, it's one of the most effective weight-saving upgrades available—and proof that true performance is often found in the details.