Centerlock lockrings are not interchangeable in all cases as they vary according to the hub type and axle. In some cases, they may also create frame clearance issues.
That said, the lockrings will work with any Centerlock rotor.
Shimano Centerlock System
Centerlock is Shimano’s way of mounting a disc-brake rotor to a hub. Centerlock hubs have splines on which the rotor slides. Then, the rotor is secured via a lockring.
The main advantage of Centerlock over the classic bolted method is that that installation and removal are faster because you only have to remove the lockring rather than 6 bolts (that are often very tight).
Externally and Internally Notched LockRings
There are two types of Centerlock lockrings – with external and internal notches (cutoffs for the hub splines).
The cutoffs of external lockrings are on the periphery.
Meanwhile, the cutoffs of internal lockrings are on the inside.
Lockrings with external splines are tightened with a bottom bracket tool whereas the lockrings with internal splines are installed and removed with a cassette tool.
When To Use Internally Notched Lockrings
Internally notched lockrings are used for hubs with quick-release skewers or thru-axles up to 12mm. If the tru-axle is bigger (15mm), the lockring either won’t fit or there won’t be enough space for the tightening socket.
Note: Some thru-axle hubs aren’t designed to operate with internally notched lockrings regardless of the axle diameter (e.g., Chris King hubs).
When To Use Externally Notched Lockrings
External spline lockrings are big enough for larger 15mm thru-axles. They can also work with 12mm thru-axles.
Size and Dimensions
The typical lockrings have the following dimensions:
| Inner Diameter | External Diameter | |
| Internally Notched Lockrings | 21.5mm | 38mm |
| Externally Notched Lockrings | 26mm | 44mm |
Advantages & Disadvantages Of Internally and Externally Notched Lockrings
It would be inaccurate to say that one is better than the other. That said, some peculiarities should be taken into consideration:
- Internally notched lockrings require a cassette tool which is more readily available. Moreover, it’s longer, and once inserted into the notches, it’s less likely to slip.
- Еxternally notched rings require a bottom bracket tool that grabs the lockring from the outside. If the tool can’t get deep enough, it can slip.
- Sometimes internally notched lockrings come with the hub or rotor for free whereas externally notched models often have to be purchased separately.
Table Summary
| When To Use | Needed Tools | Advantages | Disadvantages | |
| Internally Notched Lockring | Quick-release skewers 12mm Thru Axles | Cassette socket | The installation tool is readily available and less likely to slip | Not compatible with larger thru-axles |
| Externally Notched Lockring | Quick-release Thru-axles | Bottom Bracket Tool | Compatible with all thru-axles | The installation tool is more likely to slip and could be harder to find |
Frequently Asked Questions About Centerlock Lockrings
Should I grease the lockring before tightening it to the hub?
Some people like to apply a thin layer of grease on the threads of the lockring before tightening. The purpose of the grease is to prevent corrosion caused either by moisture and dirt or the contact between two dissimilar metals in an oxidized environment.
However, some mechanics recommend against grease as it attracts dirt and can cause contamination of the rotor. Once the rotor is dirty, it becomes slippery and causes a loss of braking power.
I don’t apply grease as I have not seen such a recommendation in Shimano’s manual, at the least at point of writing this article.
Can I install bolt-on rotors on a Centerlock hub?
Yes, with the help of a special adapter. I have a dedicated post on the subject right here.
Can I use SRAM Centerlock rotors on а Shimano Centerlock hub?
Yes. The Centerlock spline architecture is identical. As long as the rotors are labeled as Centerlock and fit the caliper that you have, the brand doesn’t matter.
Can I use Shimano lockrings with SRAM Centerlock rotors?
Yes. You can also use third-party lockrings too. As long as they are the correct type (internal or external), they will work with any Centerlock rotor.
My Centerlock tool doesn’t fit over the hub. What should I do?
You are more than likely trying to use an internally notched lockring on a hub that requires an externally notched one. Due to the lack of clearance between the axle and the lockring, you can’t slide the cassette tool in.
The only solution is to get an externally notched lockring and tighten it to the required torque, usually 40Nm.
The lockring is too tight. I can’t get it off. Any tips?
The go-to method is to apply penetrating oil to the connection points, let it sit for 15 minutes, and then use a long breaker bar (or pipe) to lengthen the removal tool. The additional length will give you the leverage you need to untighten the lockring.
Can I remove a Centerlock rotor without a special tool?
If you don’t care about saving the parts, the answer is yes. But if you want to preserve the structure intact, get the right tool for the job.
