X-Lab GT8 GRX

The X-LAB GT8 GRX is a carbon gravel bike with Shimano GRX 2x12 gearing, Shimano hydraulic disc brakes and Branta carbon wheels. The frame clears tyres up to 55mm wide and has storage in the down tube and accessory mounts for longer days off the sealed road.

Shimano GRX 2x12 gearing

Shimano GRX is Shimano's gravel-specific groupset. The GT8 runs GRX 12-speed with two chainrings, a 46T and a 30T, and an 11-36T cassette.

• Wide range: the 30T small ring and 36T sprocket give an easy gear for steep, loose climbs. The 46T big ring and 11T sprocket keep you pedalling on fast sealed descents.
• Small steps between gears: with two chainrings, the cassette doesn't need huge jumps between sprockets, so it's easier to find the right cadence on the road and in a group.
• Built for gravel: the GRX RX820 rear derailleur has a clutch that keeps the chain tight over rough ground, so it's less likely to slap the frame or come off.

A 2x setup suits riders who mix sealed roads and gravel, or ride gravel events with fast road sections. It covers almost every gradient without big gaps between gears.

Shimano GRX hydraulic disc brakes

Shimano GRX hydraulic disc brakes with 160mm rotors front and rear give strong, consistent braking in the wet and on long, loose descents. The GRX levers are shaped for gravel riding, with hoods designed for a secure grip and control on rough ground.

Carbon frame, wheels and cockpit

The frame and fork are premium Toray T-800 carbon.

X-LAB designed the seat stays to balance strength and handling precision with compliance, so the rear end takes the edge off corrugations and rough gravel. The 27.2mm carbon seat-post adds a little more flex for comfort on long rides.

The wheels are Branta C45 carbon gravel wheels, and the handlebar and stem are Branta carbon too. Branta is XDS's in-house component brand.

Room for bigger tyres

The GT8 comes with Continental Terra Trail 700 x 45C tyres, a fast-rolling all-rounder for mixed gravel and sealed roads. The frame clears tyres up to 55mm wide, so you can fit bigger, grippier tyres for rough or loose terrain, or go narrower for faster road-heavy riding.

Storage, mounts and modern standards

• In-frame storage: a compartment in the down tube for tools, a tube or food, keeping weight off your back.
• Accessory mounts: mounting points on the frame and fork, for carrying more on longer rides.
• UDH compatible: the frame uses SRAM's Universal Derailleur Hanger, so a replacement hanger is easy to find.
• T47 threaded bottom bracket: threaded shells stay creak-free longer and are simpler to service than press-fit designs.
• 12mm thru-axles: for a stiff, secure wheel fit.

Geometry and sizing

The GT8 has a 71-degree head angle (70 degrees on XS and S), 435mm chainstays and an 80mm bottom bracket drop on every size, for stable, predictable handling on loose surfaces.

Frequently asked questions

What groupset does the X-LAB GT8 GRX use?

Shimano GRX 12-speed with two chainrings (46/30T) and an 11-36T cassette, with GRX hydraulic disc brakes.

Is the X-LAB GT8 GRX 1x or 2x?

2x. It has a 46/30T GRX crankset and a front derailleur, for a wide gear range with small steps between gears.

What is the tyre clearance on the X-LAB GT8?

Up to 55mm. It comes with Continental Terra Trail 700 x 45C tyres.

Does the X-LAB GT8 have in-frame storage?

Yes. It has a storage compartment in the down tube, plus accessory mounts on the frame and fork.

What size X-LAB GT8 do I need?

XS fits riders 148 to 158cm, S 158 to 168cm, M 168 to 176cm, L 176 to 183cm, XL 183 to 191cm and XXL 191 to 202cm.

What colour is the X-LAB GT8 GRX?

Afterburner.

Who makes X-LAB bikes?

X-LAB is the performance brand of XDS, a bicycle manufacturer founded in Shenzhen in 1995. Its wheels and cockpit come from Branta, XDS's in-house component brand.