Can a steel bicycle compete with the very best endurance bikes on the market?

We believe it can. KARL RS was created to prove exactly that, combining the timeless ride quality of steel with modern engineering for cyclists who demand performance, comfort, and reliability on every ride.

Speed, comfort, durability, and versatility define the character of KARL RS. Every detail has been designed to deliver a smooth, responsive, and confidence-inspiring riding experience, whether you’re tackling long road rides or exploring less-travelled routes.

Engineered for Long-Distance Performance

Every aspect of the frame has been refined to achieve greater stiffness, efficiency, and modern performance.

Manufacturing processes have been simplified to enhance structural integrity while preserving the craftsmanship that defines every ZEN MASSIMO frame.

The updated geometry accommodates tyres up to 700×34, providing increased comfort, improved control, and greater versatility across a wide range of road surfaces.

Premium Materials and Modern Technology

KARL RS is built using Columbus Life Oversized steel tubing, carefully selected to deliver the ideal balance of stiffness, ride quality, and long-term durability.

The frame is paired with our proven stainless steel UDH dropouts, ensuring maximum compatibility with the latest drivetrain standards while simplifying maintenance.

Key technical features include:

• T47 threaded bottom bracket
• Fully integrated cable routing
• Oversized headset for a more precise and stable front end
• Clearance for tyres up to 700×34
• Performance-focused geometry designed for endurance riding

Available as a Frameset or Complete Bike

KARL RS is far more than an evolution of the original KARL.

It is available both as a frameset for riders who want to build their dream bike, and as a complete bicycle, carefully assembled with premium components to deliver exceptional performance straight from the workshop.

Browse the available configurations below and choose the version that best suits your riding style.

Sizes and Colours

KARL RS is available in six frame sizes and three exclusive colour options:

• Gold Black
• Pearl White
• Gold Red

Designed for cyclists who appreciate the unmistakable ride quality of steel without compromising on modern performance, KARL RS represents the perfect balance between Italian craftsmanship and contemporary engineering.