The Shimano GRX RD‑RX810 / RD‑RX815 Tension & Guide Pulley Set is the official Shimano replacement pulley (jockey wheel) kit used for 11-speed GRX gravel rear derailleurs, covering both mechanical and Di2 versions.
What it is
This is a replacement pulley wheel set for:
Shimano GRX RD‑RX810 (mechanical 11-speed)
Shimano GRX RD‑RX815 (electronic 11-speed)
It includes:
Guide pulley (upper jockey wheel)
Tension pulley (lower jockey wheel)
What it does
These two pulleys are responsible for:
Guide pulley
directs chain into each gear cleanly
ensures accurate shifting response
Tension pulley
maintains chain tension
stabilises drivetrain under pedalling load
Together they keep the GRX system:
smooth
quiet
precise under gravel vibration and load
Compatibility
This set is designed specifically for:
GRX RX810 / RX815 11-speed systems only
It is not compatible with:
newer 12-speed RX820 systems
MTB derailleurs
road 12-speed R-series systems
(Shimano pulley geometry is speed- and cage-specific.)
Key characteristics
Genuine Shimano OEM part
Designed for gravel vibration resistance
Directional pulley design (must be installed correctly)
Engineered tooth profile for chain retention under rough terrain
When to replace
You should replace these pulleys when:
shifting becomes noisy or imprecise
chain starts “skipping” under load
pulley teeth become hooked or worn
bearings feel rough or gritty
GRX-specific design purpose
Compared to standard road pulleys, GRX versions are tuned for:
mud and dust resistance
chain stability on rough gravel
better chain retention over bumps
reduced drivetrain noise under load
Bottom line
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The Shimano GRX RD-RX810/RX815 pulley set is a precision OEM replacement kit for 11-speed GRX gravel derailleurs, restoring smooth shifting, chain stability, and quiet drivetrain performance in rough and variable terrain.
