STONE Direct Mount Chainring for SI / SL / SISL / SISL2 & F-S-A Comet Afterburner — 3mm Inner Offset Hollow / Aero 30T–40T
The STONE Direct Mount Chainring is designed for SI, SL, SISL, SISL2 cranksets and compatible F-S-A Comet / Afterburner crank interfaces.
Made from high-stiffness 7075-T651 aerospace-grade aluminum, it offers excellent strength, precise fitment, and reliable chain retention for road, gravel, and MTB-style drivetrain setups using standard 9–12 speed chains.
Available in Hollow and Aero styles, with tooth options from 30T to 40T.
| Item | Details |
|---|---|
| Brand | STONE |
| Material | Aerospace-grade Aluminum 7075-T651 |
| Mount Type | Direct Mount |
| Offset | 3mm inner offset |
| Color Options | Black / Silver |
| Chainring Style | Hollow / Aero |
| Chain Compatibility | Standard 9 / 10 / 11 / 12-speed chains |
| Not Compatible With | Not for SRAM AXS Flattop T-Type 12S chain |
| Crank Compatibility | SI / SL / SISL / SISL2, F-S-A Comet / Afterburner |
| Thickness | 6.7mm |
| Hardness | HB150 |
| Machining Precision | 0.03mm |
| Tooth Options | 30T / 32T / 34T / 36T / 38T / 40T |
This chainring is designed to fit the following cranksets and interfaces:
It works with standard 9-speed, 10-speed, 11-speed, and 12-speed chains.
Important Notice:
This chainring does not support SRAM AXS Flattop T-Type 12-speed chains.
Please confirm your crank model and chain type before placing an order.
The Hollow style is designed for riders who prefer a lighter structure and quieter drivetrain performance.
The Aero style features a solid full-face design for stronger rigidity and a more integrated appearance.
Weights may vary slightly depending on production tolerance and tooth size.
| Teeth | Aero Style Weight | Hollow Style Weight |
|---|---|---|
| 30T | 60g | 56g |
| 36T | 85g | 72g |
| 40T | 100g | 85g |
Made from 7075-T651 aerospace-grade aluminum, this chainring provides:
Each chainring is manufactured with CNC machining accuracy of 0.03mm, ensuring:
The narrow-wide tooth profile helps improve chain retention and reduce the risk of chain drop during riding.
It also helps clear mud and dirt more effectively, supporting smoother and more reliable drivetrain performance.













