X-LAB RT9

X-LAB RT9 – The Ultimate Ultralight Carbon Road Bike

World’s Lightest Production Road Bike Frame – Built for Pure Climbing Performance

The X-LAB RT9 pushes lightweight road-bike engineering to an extraordinary level. Built around what X-LAB identifies as the world’s lightest production carbon road-bike frame, the RT9 frame is engineered to approximately 550 grams, creating an uncompromising platform for riders who demand exceptional climbing ability, rapid acceleration, precise handling and elite-level efficiency.

The complete X-LAB RT9 combines this remarkably lightweight frame with Shimano Dura-Ace Di2 electronic shifting, a Branta carbon power-meter crankset, Branta C50 ULR carbon wheels, an integrated carbon cockpit and Michelin Pro 5 tires.

The result is a complete race-ready road bike weighing approximately 6.20 kg / 13.64 lbs in size Large.

For serious climbers, racers and performance-focused road cyclists searching for one of the lightest production road bikes available, the X-LAB RT9 represents an exceptional combination of extremely low weight, premium carbon construction and competition-level components.

A Remarkable 550-Gram Carbon Frame

At the heart of the RT9 is its extraordinary carbon frame.

X-LAB constructs the RT9 using Toray T1100 and M40X carbon fiber, high-performance carbon materials selected to achieve an exceptionally low frame weight while retaining the stiffness and structural performance demanded by competitive road riding.

The frame is engineered to approximately 550 grams, making weight reduction one of the defining characteristics of the RT9.

Less mass becomes particularly valuable when the road turns upward. Every acceleration out of a switchback, every attack on a climb and every increase in gradient rewards a bicycle that minimizes unnecessary weight.

The RT9 is therefore not simply designed to be light—it is designed as a dedicated high-performance climbing platform.

Made for Climbers

The X-LAB RT9 is purpose-built for cyclists who prioritize:

• Lightweight climbing performance

• Fast acceleration

• Efficient power transfer

• Responsive road handling

• Competitive road racing

• Mountain rides and steep gradients

• Premium carbon construction

• Electronic Shimano Dura-Ace shifting

• Integrated power measurement

• Low overall bicycle weight

On long mountain climbs, reducing bicycle weight can make repeated accelerations and elevation gain more efficient. The RT9 takes this philosophy to the extreme with a complete bicycle weighing approximately 13.64 pounds in size L.

Despite its climbing focus, the RT9 is equipped with 50 mm deep carbon wheels, giving the bicycle aerodynamic capability for faster rolling terrain and high-speed road riding as well.

Shimano Dura-Ace Di2 Electronic Drivetrain

The RT9 is equipped with Shimano's flagship Dura-Ace Di2 electronic drivetrain.

The system includes:

Rear Derailleur: Shimano Dura-Ace RD-R9250 Di2
Front Derailleur: Shimano Dura-Ace FD-R9250 Di2
Shifters: Shimano Dura-Ace ST-R9270 Di2
Cassette: Shimano Dura-Ace CS-R9200, 11-34T
Chain: Shimano CN-M9100

Dura-Ace Di2 provides extremely fast, accurate electronic shifting designed for high-level road racing.

The 11-34T cassette also gives the RT9 useful climbing range for steep gradients while maintaining close gearing appropriate for competitive road riding.

Branta Carbon Power Meter Crankset

Instead of a conventional aluminum crankset, the RT9 uses a Branta carbon crankset with an integrated power meter.

Crankset Specifications

• Carbon construction

• Integrated power meter

• 52/36T chainrings

• 29 mm alloy spindle

• Apple Find My anti-theft technology

The integrated power meter allows riders to monitor training and racing output without requiring a separate aftermarket crank or pedal-based power-meter system.

For performance riders, power data can provide valuable information including effort management, pacing, training intensity and climbing performance.

Branta C50 ULR Carbon Wheelset

A lightweight bicycle needs equally serious wheels.

The X-LAB RT9 is equipped with the Branta C50 ULR carbon wheelset, featuring carbon rims and carbon spokes.

Wheel Highlights

• 50 mm carbon rims

• Carbon spokes

• Ceramic bearings

• Approximately 1,230 g wheelset weight

• Performance-oriented aerodynamic profile

The combination of a low wheel weight and 50 mm rim depth gives the RT9 an interesting balance between climbing efficiency and aerodynamic performance.

Light wheels are particularly noticeable during acceleration and repeated changes in speed, while the deeper carbon rim profile can help improve aerodynamic efficiency on faster sections of road.

Integrated Branta Carbon Cockpit

The front of the RT9 features a Branta integrated carbon handlebar and stem system.

An integrated cockpit helps reduce component count while providing the clean appearance expected from a modern premium race bike.

For the rider, the lightweight cockpit contributes to the RT9's exceptionally low overall weight while maintaining the precise front-end control needed when descending, cornering or climbing out of the saddle.

Powerful Shimano Dura-Ace Hydraulic Disc Brakes

Speed requires control.

The RT9 uses Shimano Dura-Ace BR-R9270 hydraulic disc brakes paired with Shimano rotors:

Front Rotor: 160 mm
Rear Rotor: 140 mm

Hydraulic disc braking provides strong, predictable braking performance and modulation for fast road riding, technical descents and changing weather conditions.

Michelin Pro 5 700 x 28C Tires

The RT9 comes equipped with Michelin Pro 5 700 x 28C tires.

A 28 mm road tire provides an effective balance between rolling efficiency, road feel, cornering grip and comfort.

Maximum Tire Clearance: 30C

The RT9 has a manufacturer-specified maximum tire clearance of 30C.

That is an important distinction for riders comparing the RT9 with modern endurance or all-road bicycles. The RT9 is fundamentally a lightweight performance road and climbing bike, rather than a wide-tire endurance or gravel platform.

UDH-Compatible Carbon Frame

The RT9 carbon frame is UDH compatible, providing compatibility with the increasingly common Universal Derailleur Hanger standard.

Additional frame details include:

• XDS carbon construction

• Toray T1100 + M40X carbon

• UDH compatibility

• Carbon fork

• 12 mm thru-axle system

• 27.2 mm carbon seatpost

Selle Italia SLR Boost Carbon-Rail Saddle

Completing the lightweight build is a Selle Italia SLR Boost saddle with carbon rails.

Using carbon rails further reduces weight while maintaining the performance-oriented seating platform expected on an elite road-racing bicycle.

X-LAB RT9 Specifications

Frame:
XDS Carbon Frame, Toray T1100 + M40X, UDH Compatible

Approximate Frame Weight:
550 g

Fork:
XDS Carbon Fork, Toray T1100
100 x 12 mm thru-axle

Handlebar / Stem:
Branta Carbon Integrated Cockpit

Seatpost:
XDS Carbon, 27.2 mm

Rear Derailleur:
Shimano Dura-Ace RD-R9250 Di2

Front Derailleur:
Shimano Dura-Ace FD-R9250 Di2

Shifters:
Shimano Dura-Ace ST-R9270 Di2

Brakes:
Shimano Dura-Ace BR-R9270 hydraulic disc

Cassette:
Shimano Dura-Ace CS-R9200, 11-34T

Crankset:
Branta Carbon Power Meter Crankset, 52/36T

Bottom Bracket:
BSA 29 mm

Rotors:
Shimano SM-MT900
Front: 160 mm
Rear: 140 mm

Chain:
Shimano CN-M9100

Wheelset:
Branta C50 ULR Carbon Rims & Carbon Spokes
Ceramic Bearings

Wheelset Weight:
Approximately 1,230 g

Tires:
Michelin Pro 5, 700 x 28C

Maximum Tire Clearance:
30C

Saddle:
Selle Italia SLR Boost, Carbon Rails

Complete Bike Weight:
Approximately 6.20 kg / 13.64 lbs, Size L

Sizes:
XS / S / M / L

X-LAB RT9 Size Guide

XS / 46 cm: 4'10" – 5'2" / 148–158 cm
S / 50 cm: 5'2" – 5'6" / 158–168 cm
M / 54 cm: 5'6" – 5'9" / 168–176 cm
L / 56 cm: 5'9" – 6'0" / 176–183 cm

Professional bike fitting is recommended because rider proportions, flexibility, inseam and riding position can affect the ideal size.

X-LAB RT9 Geometry

Who Is the X-LAB RT9 For?

The RT9 is an ideal choice for riders who place a premium on low weight, climbing speed and race-level road performance.

It is particularly suited to:

Climbers

At approximately 550 grams for the frame, the RT9 is designed around one fundamental objective: reducing the amount of bicycle you have to carry uphill.

Competitive Road Racers

Dura-Ace Di2, hydraulic disc brakes, carbon wheels and an integrated power meter make the RT9 ready for serious race use.

Performance-Focused Road Cyclists

Even riders who never pin on a race number can appreciate the responsiveness and acceleration of an exceptionally lightweight road bike.

Riders Looking for Something Truly Special

Many premium road bikes are light. The RT9 occupies a much more extreme category, combining a roughly 550-gram production frame with a complete build weighing approximately 6.2 kg.

Why Buy the X-LAB RT9 from Bike Attack?

Buying a bicycle at this performance level is about more than ordering a box.

At Bike Attack in Santa Monica, customers can receive professional assistance with sizing, assembly, setup, adjustments and ongoing service.

A high-end carbon road bike equipped with electronic shifting, hydraulic brakes, an integrated cockpit and a power meter deserves careful professional preparation.

Bike Attack can help riders select the proper size and ensure their RT9 is correctly assembled and prepared before its first serious ride.

Bike Attack – Santa Monica, California.

Bike Attack
2904 Main Street
Santa Monica, CA 90405

bikeattack.com

Professional bicycle assembly, service and expert support available.

Nationwide shipping available.

X-LAB RT9 – When Every Gram Matters

The X-LAB RT9 is built around an extraordinary proposition: create an exceptionally lightweight production road frame without abandoning the stiffness, precision and component technology expected from a modern elite road machine.

With its approximately 550-gram Toray T1100 + M40X carbon frame, 6.20 kg complete-bike weight, Shimano Dura-Ace Di2 drivetrain, integrated power meter, Branta C50 ULR carbon wheelset, carbon cockpit and hydraulic disc brakes, the RT9 is an unapologetically performance-focused road bicycle.

For the rider chasing elevation, acceleration and minimum weight, the X-LAB RT9 belongs among the most remarkable lightweight production road bikes available today.

Specifications, components, colors and weights are subject to manufacturer changes. Contact Bike Attack for current availability and exact specifications.

Technical Specifications