STONE Rear Derailleur Pulley Wheel Set: 11T–17T Guide & Jockey Rollers for Shimano M370/X4 and Most 8–12 Speed Chains
Stone Pulley Wheel Guide & Jockey Roller
Upgrade your rear derailleur with Stone pulley wheels, offered in 11T, 13T, 15T, and 17T for road and MTB bikes. They are compatible with Shimano M370 (X4) and most rear derailleurs.
Key Specifications
- Material: POM high-strength resin
- Bearing: Japan NSK 689-2RS
- Teeth options: 11T / 13T / 15T / 17T
- Weight: 9g / 10g / 12g / 15g
- Thickness: 8mm
- Inner diameter: 6mm (compatible with 4/5mm)
- Color: black wheel with black cover, or black wheel with red cover
Chain Compatibility
These pulley wheels fit most brand chains of 8, 9, 10, 11, and 12 speed.
Important: They do not work with SRAM brand road bike 12s AXS Flattop chains.
Using Shimano 12s Road Bike Chains
If you have a Shimano brand 12s road bike chain, you must remove the original chain quick link. The original Shimano 12s road quick link is too narrow for this pulley. Switching to any other brand 12s quick link will make it fit and work correctly.
Size Reference Chart
| Tooth | Outer Diameter | Weight | Fit For |
|---|---|---|---|
| 10T | 44mm | 8g | Some Campagnolo |
| 11T | 44.05mm | 8g | 95% of rear derailleurs |
| 13T | 52mm | 10.5g | Long arm, down part |
| 15T | 59.6mm | 12g | SRAM, down part |
| 17T | 68mm | 14g | Requires a special large-size derailleur board frame |
Modification Advice and Principles
If you plan to modify your drivetrain, follow these guidelines:
- Top (guide) pulley: It should be smaller than the lower pulley. If it is too big, it will hit the cassette flywheel. The maximum size you can use is 1 tooth bigger than your current one.
- Lower (tension) wheel: You can increase by 1–2 teeth based on your current size. A bigger wheel rolls more easily, which helps your riding.
- Single chainring setups: We recommend changing to a narrow-wide tooth pulley for better performance.
Example
- If your top guide wheel is 11T, the maximum you can change to is 12T — 13T would be too big.
- If your lower tension wheel is 11T, you can change it to 12T or 13T — either works fine.
About POM Material
Polyoxymethylene (POM), also known as acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts that require high stiffness, low friction, and excellent dimensional stability.
POM offers high strength, hardness, and rigidity down to −40 °C.
Typical applications include high-performance engineering components such as small gear wheels, eyeglass frames, ball bearings, ski bindings, fasteners, guns, knife handles, and lock systems. The material is widely used in the automotive and consumer electronics industries.
