Controlled Gravel Braking Performance with 2x Shifting Comfort.

The Shimano GRX ST-RX600 / BR-RX400 Set combines a left 2-speed STI shift/brake lever with a powerful BR-RX400 Flat-Mount caliper and is specially designed for gravel, all-road, and road bikes. This gives you precise 2-speed shifting and powerful, finely modulated disc braking at the front wheel in one package.

The ST-RX600 brake/shift lever features ergonomic GRX feel with plenty of control in both the tops and drops – ideal on gravel, descents, and long tours. The reach can be individually adjusted with a tool, so even smaller hands can grip securely. The integrated shift lever reliably controls your 2-speed GRX or road bike setup at the front derailleur.

The BR-RX400 caliper with 2 pistons is made of robust aluminum and is mounted via Flat-Mount to the frame or fork – the standard for modern gravel and road bikes. The pre-assembled SM-BH90-JK-SSR brake hose (approx. 900 mm) is already filled, but the STI is not yet connected – perfect if you want to cleanly shorten the hose and route it individually.

The set includes L03A Resin pads with cooling fins, which ensure quiet braking, good wet braking performance, and improved heat management. Shimano recommends combining them with SM-RT64 brake rotors, but the set is compatible with many Centerlock rotors of the appropriate size.

Highlights:

• Complete Front Set: left 2-speed GRX STI + Flat-Mount caliper with pre-assembled hose for the front wheel.
• Gravel-specific Ergonomics: secure grip on loose ground thanks to GRX lever geometry.
• Powerful Disc Brake: 2-piston BR-RX400 caliper made of aluminum, tuned for gravel/all-road use.
• Pre-assembled Hydraulics: system filled, SM-BH90 brake hose approx. 900 mm – STI not yet connected for individual length adjustment.
• L03A Resin Pads with Cooling Fins: quiet braking power with optimized heat management.

Technical Data:

• Brand: Shimano
• Group: GRX
• Model: ST-RX600 / BR-RX400
• Position: Front wheel (FW), left lever
• Area of Use: Gravel, Road, Cyclocross, All-Road
• Front Shifting Speeds: 2-speed (front derailleur control)
• Brake Type: hydraulic disc brake
• Brake Lever: ST-RX600, Dropbar STI, 2-speed
• Reach Adjustment: integrated, adjustable with tool
• Brake Lever Material: Aluminum
• Caliper: BR-RX400, Flat-Mount, 2 pistons, Aluminum
• Brake Hose: SM-BH90-JK-SSR, approx. 900 mm, pre-assembled & filled (STI not connected)
• Pads: L03A Resin with cooling fins
• Recommended Brake Rotor: SM-RT64 (Centerlock, appropriate size)
• SERVO-WAVE: no
• Adjustable Free Stroke: no
• Color: black
• Product Category: Disc Brake (hydraulic, Road/Gravel)

Scope of Delivery:

• 1 x Shimano GRX ST-RX600 Shift/Brake Lever left | 2-speed
• 1 x Shimano BR-RX400 Caliper | Flat-Mount | 2-Piston
• 1 x SM-BH90-JK-SSR Brake Hose, approx. 900 mm, System filled, STI not connected
• 1 x Pair of Shimano L03A Resin Brake Pads with Cooling Fins (pre-assembled)
• Note: Workshop packaging (without additional attachments such as brake rotors or screws)

Manufacturer Article No.: IRX4001DLF6SC100A | EAN: 4550170449919

The GRX ST-RX600 / BR-RX400 Set is the ideal solution if you want to upgrade your gravel or road bike to a powerful, hydraulic disc brake with 2-speed STI control at the front.