Ready for Long Days Beyond the Seal
The X-LAB GT8 is a carbon gravel bike for riders who like to mix quiet back roads, gravel climbs and longer adventures. It combines Shimano GRX Di2 electronic shifting with carbon wheels, 45 mm tyres and plenty of mounting points for carrying gear.
The Slipstream finish brings a blue and silver colourway to a bike that is equally at home on a fast gravel ride or a more relaxed weekend exploring. With clearance for tyres up to 55 mm, there is room to adjust the setup as your riding changes.
Toray T800 Carbon Frame
The GT8 uses a Toray T800 carbon frame and carbon fork. Its gravel-focused geometry is designed to provide stable handling on loose roads while keeping the bike responsive when you are climbing or riding on seal.
The frame includes in-frame storage for ride essentials, along with mounting points on the frame and fork for bottles and compatible accessories. It is also compatible with a Universal Derailleur Hanger.
Shimano GRX Di2 Electronic Shifting
Shimano GRX RX717 Di2 provides electronic shifting designed for gravel riding. The single-chainring setup keeps the controls simple, while the wide-range gearing gives you options for steep gravel climbs and longer days carrying gear.
A 40T narrow-wide chainring helps keep the chain engaged over uneven surfaces. Shimano GRX hydraulic disc brakes and 160 mm rotors provide controlled braking when the weather changes or the road drops away.
Power Meter and Apple Find My
The Branta alloy crankset includes a power meter, so you can measure your effort, follow structured training or pace yourself on a long climb without buying a separate unit.
Apple Find My compatibility is also integrated into the crankset. It can help locate the bike through a compatible Apple device and account, but it does not replace a quality physical lock when the bike is left unattended.
Carbon Wheels and Room for Wider Tyres
The Branta C45 GT carbon wheelset is supplied with Continental Terra Trail 700 × 45C tyres. That is a useful starting point for riders who want comfort and grip on gravel without giving up road speed.
X-LAB states a maximum tyre clearance of 55 mm. Wider tyres can offer more cushioning and grip on rougher roads, although actual clearance depends on the tyre and rim combination. Always leave suitable room for mud and debris.
Carbon Cockpit and Contact Points
A Branta carbon gravel handlebar and carbon stem keep the cockpit light while allowing more flexibility for fit changes than a one-piece bar and stem. An XDS 27.2 mm carbon seatpost and Fizik Terra Argo X7 saddle complete the contact points.
Handlebar width, stem length and crank length vary by frame size. Check the measurements below or talk to our team if you are between sizes.
Key Features
- Toray T800 carbon frame and carbon fork
- Gravel-focused geometry
- Shimano GRX RX717 Di2 electronic 1 × 12-speed shifting
- Shimano GRX hydraulic disc brakes
- Branta alloy power-meter crankset with 40T chainring
- Apple Find My compatibility integrated into the crankset
- Branta C45 GT carbon wheels
- Continental Terra Trail 700 × 45C tyres
- Stated maximum tyre clearance of 55 mm
- In-frame storage
- Accessory mounting points on the frame and fork
- Branta carbon gravel handlebar and carbon stem
- XDS 27.2 mm carbon seatpost
- Universal Derailleur Hanger compatibility
- Slipstream blue and silver finish
- Claimed weight: 8.78 kg in size M
Who Is It For?
- Gravel roads and mixed-surface riding
- Long weekend adventures
- Fast gravel training and events
- Riders who want electronic shifting
- Riders using power for training or pacing
- Bikepacking and rides that require extra gear
- Road riders wanting to explore beyond sealed roads
The GT8 has mounts for carrying equipment, but the carbon frame and fork still have load limits. Check the manufacturer’s requirements and the fit of any rack or bag before loading it for a trip.
Our Thoughts
The GT8 comes with many of the parts gravel riders often end up adding later: carbon wheels, electronic shifting and a power meter are already on the bike. The 45 mm Continental tyres are a good match for the sort of mixed gravel and sealed-road riding many of us do in New Zealand.
We also like the room for wider tyres and the frame and fork mounts. You can set it up for a quick after-work ride, then add bags and more tyre volume for a longer trip.
The 1 × drivetrain keeps things straightforward, although riders who spend most of their time in fast road bunches may prefer a 2 × setup with smaller steps between gears. For riders whose routes regularly leave the seal, the GT8 is a well-equipped option.
Technical Specifications
Frameset
- Frame: X-LAB carbon, Toray T800, UDH compatible
- Fork: X-LAB carbon, 12 × 100 mm front thru-axle
- Frame storage: Integrated storage
- Mounting points: Frame and fork accessory mounts
- Stated maximum tyre clearance: 55 mm
Drivetrain
- Shifters: Shimano GRX ST-RX717 Di2
- Rear derailleur: Shimano GRX RD-RX717 Di2
- Crankset: Branta aluminium power-meter crankset, 29 mm aluminium spindle
- Chainring: 40T narrow-wide
- Bottom bracket: T47, listed as 24 mm
- Security technology: Apple Find My compatibility
Brakes
- Brakes: Shimano GRX BR-RX715 hydraulic disc
- Front rotor: Shimano SM-RT70, 160 mm
- Rear rotor: Shimano SM-RT70, 160 mm
Wheels and Tyres
- Wheelset: Branta C45 GT carbon
- Spokes: Steel
- Tyres: Continental Terra Trail, 700 × 45C
Cockpit and Contact Points
- Handlebar: Branta Gravel carbon
- Stem: Branta carbon
- Seatpost: XDS carbon, 27.2 mm
- Saddle: Fizik Terra Argo X7
Sizes, Colour and Weight
- Sizes: XS, S, M, L, XL and XXL
- Colour: Slipstream, blue and silver
- Claimed weight: 8.78 kg in size M
Size Guide
| Size | Recommended Rider Height | Stem | Handlebar | Crank | Seatpost |
|---|---|---|---|---|---|
| XS | 148–158 cm | 70 mm | 370/430 mm | 165 mm | 300 mm |
| S | 158–168 cm | 70 mm | 370/430 mm | 165 mm | 300 mm |
| M | 168–176 cm | 80 mm | 390/450 mm | 170 mm | 350 mm |
| L | 176–183 cm | 90 mm | 390/450 mm | 170 mm | 350 mm |
| XL | 183–191 cm | 100 mm | 410/470 mm | 172.5 mm | 350 mm |
| XXL | 191–202 cm | 100 mm | 410/470 mm | 172.5 mm | 350 mm |
Rider height is a starting point only. Body proportions, flexibility and preferred riding position can affect the best size. Contact Chain Reaction for personalised sizing advice.
Geometry
All lengths are in millimetres unless otherwise stated.
| Measurement | XS | S | M | L | XL | XXL |
|---|---|---|---|---|---|---|
| Stack | 519 | 540 | 565 | 584 | 607 | 631 |
| Reach | 370 | 379 | 384 | 392 | 399 | 408 |
| Head-tube angle | 70° | 70° | 71° | 71° | 71° | 71° |
| Head-tube length | 80 | 100 | 120 | 140 | 165 | 190 |
| Seat-tube angle | 76° | 75° | 74° | 74° | 73° | 73° |
| Seat-tube length | 435 | 447 | 471 | 491 | 532 | 577 |
| Chainstay length | 435 | 435 | 435 | 435 | 435 | 435 |
| Bottom-bracket drop | 80 | 80 | 80 | 80 | 80 | 80 |
| Wheelbase | 1,020 | 1,032 | 1,031 | 1,046 | 1,061 | 1,078 |
| Top-tube length | 506 | 525 | 547 | 566 | 585 | 605 |
| Front centre | 598 | 610 | 609 | 624 | 638 | 655 |
| Standover height | 715 | 730 | 755 | 773 | 807 | 838 |
| Fork offset | 55 | 55 | 50 | 50 | 50 | 50 |
| Trail | 75 | 72 | 70 | 70 | 70 | 70 |
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 setup and pairing assistance
- Expert gravel-bike sizing and setup advice
- Initial cockpit and saddle setup
- Practical maintenance advice at handover
- Finance and WorkRide options available
Visit Chain Reaction at 4/218 Moorhouse Avenue, Christchurch. There are more than 200 free car parks on-site, along with room to discuss sizing and setup.
Specifications are based on supplier information and may change without notice. Claimed weight is for a size M bike and may vary with frame size and production components.
