The Clarks Centerlock External Lockring is a critical component designed to provide maximum axle clearance and a secure interface for your disc brake rotors. While standard internal lockrings use a cassette tool for installation, the External version is engineered specifically for modern 15mm and 20mm thru-axle hubs. Because these larger axles often physically block a standard cassette tool from entering the hub, the external lockring moves the tool interface to the outside diameter, allowing you to use a common 16-notch bottom bracket tool for installation and removal.
Constructed from high-grade aluminum, this lockring follows the industry-standard 35.5mm splined interface, making it compatible with almost any centerlock-ready hub and rotor combination (Shimano, SRAM, Magura, etc.). Its low-profile design ensures it clears the dropouts of most modern mountain and gravel bike forks while providing a high-torque connection that prevents rotor movement or creaking under heavy braking loads.
External Tool Interface: Utilizes a standard 16-notch, 44mm OD bottom bracket tool (e.g., Park Tool BBT-9 or BBT-69.2). This is a "must-have" for bikes with oversized thru-axles where internal tools cannot fit.
Universal Spline Compatibility: Fully compatible with the standardized 35.5mm centerlock interface, allowing it to secure rotors from Shimano, SRAM, and other major manufacturers.
High-Grade Aluminum Construction: Precision-machined to be both lightweight and durable, resisting corrosion while providing a rock-solid clamp on the splined hub.
Axle Clearance Mastery: Designed to accommodate 12mm, 15mm, and 20mm thru-axles, making it a versatile "problem solver" for diverse bike fleets.
Low-Profile Design: Engineered to minimize the stack height, ensuring no interference with fork lowers or frame dropouts on tight-clearance road and gravel builds.
Lightweight Performance: Adds minimal rotational mass to the wheel, keeping your bike quick and responsive.
| Feature | Specification |
| Material | High-Grade Aluminum |
| Tool Interface | 16-Notch 44mm External (BB Tool) |
| Interface Standard | Centerlock (35.5mm) |
| Hub Compatibility | QR, 12mm, 15mm, 20mm Thru-Axle |
| Torque Spec | 40 Nm |
| Weight | ~10–12g |
Mountain Bike & Thru-Axle Owners: If your hub has a 15mm or 20mm front axle, this lockring is likely a mechanical necessity to clear the axle's outer diameter.
Simplified Maintenance: Ideal for riders who prefer carrying fewer tools; if you already have an external BB tool in your kit, you don't need to carry a separate cassette tool to manage your rotors.
Performance Upgraders: A great replacement for heavy, steel internal lockrings, offering a cleaner look and improved tool engagement.
Ultra-Tight Fork Clearance: On some specific road or gravel forks, an external lockring can occasionally rub against the inner fork blade. In these rare cases, a low-profile internal lockring is required.
Standard QR Users: While it will work on quick-release hubs, most QR setups naturally have space for an internal lockring, which is slightly lighter and lower profile.
When installing your Clarks External Lockring, always use a calibrated torque wrench set to 40Nm. Because the splines are on the outside, it is easier to "cam out" and slip if you aren't applying even pressure. A thin layer of anti-seize or grease on the threads is highly recommended to prevent galvanic corrosion between the aluminum lockring and the hub, especially if you ride in wet or salty conditions. If you're using this on a new wheelset, check your fork clearance—if there's less than 2mm of space between the lockring and the fork, consider using a specialized "thin-flange" model!
