When considering new bike wheels, hubs, or disc brakes, you'll encounter the terms "6-bolt" or "Centerlock." While you might already know that these refer to how disc brake rotors are attached to a bicycle's hub, many beginners wonder which is better or which they should fit to their road bike.

Therefore, this time, we will explain what 6-bolt and Centerlock are, as well as the advantages and disadvantages of both, hoping to be of some help in your cycling life.

The first important thing to note about Centerlock or 6-bolt rotors is that both Centerlock and 6-bolt systems work with disc brakes, regardless of the disc brake manufacturer. They will work with either rotor type.

This is because the names "6-bolt" or "Centerlock" refer to how the rotor is mounted to the hub. As long as the rotor is mounted to the hub and correctly centered, the brakes don't care; they will grab it and slow you down.

What is a 6-bolt Disc Rotor?

The 6-bolt rotor dates back to the early days of disc brakes on mountain bikes. Previously, they became the industry's preferred option for mounting rotors to your hub. 6-bolt rotors are attached to the hub using six Torx head bolts.

Securing a 6-bolt rotor to a hub is an easy process. However, it can be stripped very easily. It's always a good idea to use a torque wrench when installing them. If you overtighten and don't strip anything, there's also a risk of failure while riding, so be careful.

Also, when tightening the bolts, you must follow a star-style pattern. If you don't follow this pattern, there's a high chance you're mounting the rotor off-center. Unless you carry a Torx key, you'll end up with a scuffed or unpleasant sounding ride.

It is also recommended to regularly check the torque of the bolts. While riding, bolts can vibrate loose. If one bolt is tight and the opposite bolt is loose, your rotor will become off-center and start rubbing against the disc pads.

However, it's not all doom and gloom. 6-bolt rotors are usually lighter than Centerlock rotors, and they are much easier to find if you need new ones. You always need to check the size, not just the style you need.

Advantages and Disadvantages of 6-bolt Disc Rotors　

Advantages

・Multiple rotor options

・Cheaper than Centerlock

・Rotors are readily available

Disadvantages

・Easy to strip during installation

・Can fail while riding

・Can be accidentally mounted off-center

・Prone to warping

What is a Centerlock Disc Rotor?

Centerlock rotors are the newest rotors on the market. They were introduced to the market by Shimano, and instead of attaching to the hub using six small Torx key bolts, they use a new tool. The tool used is the Shimano TL-LR10, which can also be used for tightening cassettes.

One of the drawbacks everyone mentions about Centerlock rotors is that they are slightly heavier than 6-bolt rotors. This is because Centerlock rotors are in two parts. The outer steel part, which does the braking, is bonded to an aluminum part that connects to the hub.

The inner aluminum piece has a series of small splines in the center. These splines align with other splines on the hub body, showing how they link. This is similar to how a cassette and freehub align. This fitting system makes Centerlock easier to fit and set up compared to 6-bolt rotors.

Fortunately, this two-piece system makes it very difficult, almost impossible, for the disc rotor to warp. This is good news if you frequently warp your discs. The aluminum does an excellent job of dissipating heat, which helps keep everything wonderfully true.

The best thing about Centerlock rotors is that once you install them, they are centered and they stay centered. You'll never have scuffing issues again. Not only are they easy to center, but they are also easy to remove. With the right tool, it only takes a few seconds to tighten or loosen a Centerlock rotor.

Advantages and Disadvantages of Centerlock Disc Rotors　

Advantages

・Easy to center

・Rotors are less prone to warping

・Easy to remove

Disadvantages

・Fewer hub options

・Heavier rotors

・Requires a special Centerlock tool

When should you choose a Centerlock rotor?

One of the benefits of Centerlock that hasn't been explained yet is that Shimano manufactures Ice Tech Freeza rotors. These rotors are exactly what you need on hot days with long descents.

Available in both road and mountain bike formats, Ice Tech Freeza Centerlock rotors can reduce rotor temperatures by up to 50°. When paired with Ice Tech disc pads, you can see rotor temperatures drop from 400° to 300°.

Lower temperatures result in consistent braking power. You'll never again have to feel a loss of sustained braking on the most technical descents. It's great to know that when you hit the brakes, you'll get consistent power.

So, if you like to ride technical downhills, try Centerlock and see how your braking performs.

When should you choose a 6-bolt rotor?

If you already have 6-bolt pattern hubs and don't want to change your wheels, then 6-bolt rotors are your best option. If you have brand loyalty to SRAM, you likely won't want to switch to Centerlock as Shimano patented Centerlock, so you won't see SRAM Centerlock rotors.

If you're a weight weenie, 6-bolt is also recommended. The lightest rotors you can buy are 6-bolt, and they more than compensate for the weight of the rotor bolts. So, if you're doing a hill climb TT or chasing a KOM, a slight benefit from lighter brakes is recommended.