The 18mm hood height bump is the whole reason GRX levers exist as a separate lineup instead of just rebadged 105. Shimano raised the pivot axis on the ST-RX600 so the hoods sit taller and the brake lever curves further inboard, which changes how the bar feels when you're on the tops on rough ground and how much leverage you get braking from the hoods on a descent. Everything else here — the 11-speed cable pull, the hydraulic master cylinder internals, the reach adjust screw behind the hood — is the same architecture as 105-tier road, just repackaged for gravel ergonomics.

These are the mechanical 2x11 versions, sold as separates: ISTRX600LI is the left (front derailleur) lever, ISTRX600RBI is the right (rear derailleur) lever. Neither includes a hose or caliper in the box, so plan on pairing them with BR-RX400 or BR-RX810 flat mount calipers and an SM-BH90 hose kit if you're building from scratch. The right lever can also run as a 1x with a compatible clutch derailleur (RD-RX810 or RD-RX812) — the shifter itself doesn't care whether there's a front derailleur on the other side.

Textured rubber runs across the brake blade and the outboard face of the hood, which is the piece riders tend to underrate until they've had wet hands slide off a smooth hood on a fireroad descent. The reach adjust mechanism is tool-accessible without pulling the hood cover, so small-handed riders or anyone running deep-drop bars can dial the lever closer without a full disassembly. Shift feel is standard Shimano cable-actuated 11-speed — light lever throw, defined click at each gear, front derailleur trim positions on the left lever.... Read More