X-LAB GT8 GRX717 Di2 Recon Green
Electronic Shifting, Carbon Wheels and Proper Gravel Capability
The X-LAB GT8 GRX717 Di2 Afterburner is a carbon gravel bike for riders who want to combine speed with the ability to explore rougher roads and longer mixed-surface routes.
Its stable geometry, 700 × 45C Continental tyres and clearance for tyres up to 55 mm make it suitable for everything from fast gravel rides to long days carrying extra gear. Shimano GRX Di2 electronic shifting, a Branta power-meter crankset and Branta C45 carbon wheels give this build a strong performance focus.
In-frame storage and mounting points on the frame and fork add the practical details needed for longer rides, while the broad six-size range makes it easier to find a suitable position.
Designed for Mixed-Surface Riding
The GT8 is designed to feel settled on loose gravel without becoming slow or vague on sealed roads. Its relatively long 435 mm chainstays and low 80 mm bottom-bracket drop help create a planted riding position when the surface becomes rough or unpredictable.
The carbon frame is paired with a carbon fork and cockpit, helping keep the claimed weight to 8.78 kg in size Medium. It is light enough for fast riding while retaining the tyre clearance and mounting options expected from a capable modern gravel bike.
Clearance for Tyres up to 55 mm
Continental Terra Trail 700 × 45C tyres are fitted as standard. They provide useful volume, cushioning and grip for gravel roads while remaining practical for mixed rides that include sealed sections.
The frame offers clearance for tyres up to 55 mm, giving riders the option of adding more comfort and traction for rougher routes. Actual clearance can vary with the tyre model, rim width and measured tyre size, so compatibility should be checked before fitting tyres near the maximum width.
Shimano GRX Di2 1 × 12 Drivetrain
Shimano GRX RX717 Di2 provides electronic 12-speed shifting without the complication of a front derailleur. A 40T narrow-wide chainring is paired with a wide-range 10–51T cassette, giving the GT8 useful gearing for steep gravel climbs and faster open roads.
The single-chainring layout keeps operation simple and removes the overlap found in many two-chainring drivetrains. The broad cassette range is particularly useful on loose climbs, longer adventure rides and routes carrying extra equipment.
Branta Power-Meter Crankset
The Branta aluminium crankset includes an integrated power meter, allowing riders to measure and manage their effort during training, racing and long-distance events.
Apple Find My compatibility is also built into the crankset, providing an additional way to locate the bike through a compatible Apple device and account. It is a useful extra but does not replace a suitable physical lock when the bike is left unattended.
Branta C45 Carbon Gravel Wheels
The Branta C45 GT carbon wheelset reduces rotating weight while providing an aerodynamic rim profile for faster gravel and road sections. Steel spokes are used for dependable everyday serviceability.
The wheels are matched to 45C tyres as standard, creating a setup that balances speed, grip and comfort without immediately requiring an upgrade.
Carbon Gravel Cockpit
A Branta carbon stem and flared carbon gravel handlebar complete the cockpit. The handlebar width is matched to the frame size, with wider measurements on the larger bikes.
The flared drops provide additional control on rough descents while retaining a conventional road-style position on the hoods. A 27.2 mm carbon seatpost adds some useful compliance beneath the rider.
In-Frame Storage and Accessory Mounts
Integrated frame storage provides space for compact tools, spares and ride essentials without requiring a large saddle bag. Additional mounts on the frame and fork allow the bike to be set up for longer gravel rides, bikepacking and unsupported events.
Accessory fit, load limits and tyre clearance should be checked when planning a heavily equipped setup.
Key Features
- X-LAB Toray T800 carbon frame
- UDH-compatible rear derailleur hanger
- X-LAB carbon fork with 12 x 100 mm thru-axle
- Clearance for tyres up to 55 mm
- In-frame storage
- Accessory mounts on the frame and fork
- Shimano GRX RX717 Di2 electronic 1 × 12 drivetrain
- Wide-range Shimano 10–51T cassette
- Branta aluminium power-meter crankset
- 40T narrow-wide chainring
- Apple Find My compatibility integrated into the crankset
- Shimano GRX hydraulic disc brakes
- 160 mm front and rear brake rotors
- Branta C45 GT carbon gravel wheelset
- Continental Terra Trail 700 × 45C tyres
- Branta carbon stem and gravel handlebar
- Fizik Terra Argo X7 saddle
- Claimed weight: 8.78 kg in size Medium
- Afterburner Black finish
Who Is It For?
- Fast gravel and mixed-surface riding
- Long-distance gravel events
- Adventure riding and lightweight bikepacking
- Riders wanting electronic 1 × 12 shifting
- Training with power
- Riders wanting more tyre clearance than a conventional gravel race bike
- Anyone wanting a carbon gravel bike that is already equipped with carbon wheels
The wide-range 1 × 12 drivetrain is well suited to gravel climbing and changing terrain. Riders who spend most of their time in fast road groups may prefer the smaller gear steps and higher top-end gearing of a two-chainring road or all-road drivetrain.
Our Thoughts
The GT8 offers a lot of equipment for its price. Shimano GRX Di2, a power meter and carbon wheels are normally the first major upgrades riders consider, but all three are already included here.
The 55 mm tyre clearance also gives the bike a broader range than many gravel race bikes. It can be kept quick with the standard 45C tyres or fitted with larger tyres for rougher back roads and longer adventure rides.
The 10–51T cassette will appeal to riders tackling steep or loose climbs, although the jumps between gears are wider than you would find on a close-ratio road cassette. For mixed-surface riding, gravel events and exploring further from sealed roads, it is a practical build with very little that needs changing.
Why Buy from Chain Reaction?
- Professionally assembled, tuned and safety checked
- Brakes professionally checked and bedded in
- Shimano Di2 system checked and configured
- Power meter checked and paired where required
- Gear adjustment and drivetrain setup
- Tyre pressures initially set for the rider and intended terrain
- Expert sizing and setup advice
- Complete bike handover and feature walkthrough
- Finance and WorkRide options available
Visit Chain Reaction at 4–218 Moorhouse Avenue, Christchurch. There are more than 200 free onsite car parks, along with plenty of room for sizing and test riding.
Technical Specifications
Frameset
- Frame: X-LAB carbon, Toray T800 and UDH compatible
- Fork: X-LAB carbon, 12 x 100 mm thru-axle
- Storage: Integrated in-frame storage
- Mounts: Accessory mounting points on frame and fork
- Maximum stated tyre clearance: 55 mm
Drivetrain
- Shifters: Shimano GRX ST-RX717 Di2
- Rear derailleur: Shimano GRX RD-RX717 Di2
- Drivetrain: Electronic 1 × 12
- Cassette: Shimano CS-M6100-12, 10–51T
- Chain: Shimano CN-M6100
- Crankset: Branta aluminium power-meter crankset with Apple Find My compatibility
- Chainring: 40T narrow-wide
- Crank spindle: 29 mm aluminium
- Bottom bracket: T47 inboard, 29 mm
Brakes
- Front brake: Shimano GRX BR-RX715 hydraulic disc
- Rear brake: Shimano GRX BR-RX715 hydraulic disc
- Rotors: Shimano SM-CL700, 160 mm front and rear
Wheels and Tyres
- Wheelset: Branta C45 GT carbon gravel
- Spokes: Steel
- Tyres: Continental Terra Trail, 700 × 45C
- Maximum stated tyre clearance: 700 × 55C
Cockpit and Contact Points
- Stem: Branta carbon
- Handlebar: Branta carbon gravel handlebar
- Seatpost: XDS carbon, 27.2 mm
- Saddle: Fizik Terra Argo X7
- Pedals: Not specified
Sizes, Colour and Weight
- Sizes: Extra Small, Small, Medium, Large, Extra Large and 2XL
- Colour: Afterburner Black
- Claimed weight: 8.78 kg in size Medium
Geometry
| Measurement | XS | S | M | L | XL | 2XL |
|---|---|---|---|---|---|---|
| Stack | 519 mm | 540 mm | 565 mm | 584 mm | 607 mm | 631 mm |
| Reach | 370 mm | 379 mm | 384 mm | 392 mm | 399 mm | 408 mm |
| Head-tube angle | 70° | 70° | 71° | 71° | 71° | 71° |
| Head-tube length | 80 mm | 100 mm | 120 mm | 140 mm | 165 mm | 190 mm |
| Seat-tube angle | 76° | 75° | 74° | 74° | 73° | 73° |
| Seat-tube length | 435 mm | 447 mm | 471 mm | 491 mm | 532 mm | 577 mm |
| Chainstay length | 435 mm | 435 mm | 435 mm | 435 mm | 435 mm | 435 mm |
| Bottom-bracket drop | 80 mm | 80 mm | 80 mm | 80 mm | 80 mm | 80 mm |
| Wheelbase | 1,020 mm | 1,032 mm | 1,031 mm | 1,046 mm | 1,061 mm | 1,078 mm |
| Top-tube length | 506 mm | 525 mm | 547 mm | 566 mm | 585 mm | 605 mm |
| Front centre | 598 mm | 610 mm | 609 mm | 624 mm | 638 mm | 655 mm |
| Standover height | 715 mm | 730 mm | 755 mm | 773 mm | 807 mm | 838 mm |
| Fork offset | 55 mm | 55 mm | 50 mm | 50 mm | 50 mm | 50 mm |
| Trail | 75 mm | 72 mm | 70 mm | 70 mm | 70 mm | 70 mm |
Component Sizing
| Component | XS | S | M | L | XL | 2XL |
|---|---|---|---|---|---|---|
| Stem | 70 mm | 70 mm | 80 mm | 90 mm | 100 mm | 100 mm |
| Handlebar | 370/430 mm | 370/430 mm | 390/450 mm | 390/450 mm | 410/470 mm | 410/470 mm |
| Crank length | 165 mm | 165 mm | 170 mm | 170 mm | 172.5 mm | 172.5 mm |
| Seatpost length | 300 mm | 300 mm | 350 mm | 350 mm | 350 mm | 350 mm |
Size Guide
- Extra Small: 148–158 cm
- Small: 158–168 cm
- Medium: 168–176 cm
- Large: 176–183 cm
- Extra Large: 183–191 cm
- 2XL: 191–202 cm
Rider height is only a starting point. Body proportions, flexibility, riding style and preferred handlebar position can influence the best size. Contact Chain Reaction for personalised sizing advice before ordering.
Assembly and Setup
Every X-LAB GT8 is professionally assembled, tuned and safety checked by the Chain Reaction workshop before handover.
- Complete workshop assembly and safety inspection
- Shimano GRX Di2 system checked and configured
- Gear adjustment and drivetrain setup
- Brakes professionally checked and bedded in
- Power meter checked and paired where required
- Wheels, tyres and fasteners inspected
- Handlebar, saddle and controls initially positioned
- Tyre pressures set for the rider and intended terrain
Specifications Disclaimer
Specifications are based on current supplier and manufacturer information and may change without notice. Equivalent components may be substituted depending on production availability.
Maximum tyre clearance depends on the fitted tyre, rim width and measured tyre dimensions. Claimed weight is based on a size Medium bike and may vary with frame size, finish and component variation.
