Disc brakes - center lock versus 6 bolt

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Since cross is coming and gravel is coming (have had multiple emails recently referencing "the fall gravel season") and fall is coming and all of that, and all of that means disc brakes more and more each year, it's time to go through the differences between center lock and 6 bolt disc brakes.

Slight smoke break here - congratulations for finding this page and thanks for reading. We'd like to offer you free US domestic shipping on any order over $100. Just use code "ilearnedsomething" at checkout. And now we return to our regular programming. 

Because we'd be dumb not to accommodate as much personal consumer preference as possible, almost all of our builds are available with either 6 bolt or center lock. There are certain hubs like Chris King where some axle types (12mm) are only available for center lock and some are only available with 6 bolt (15mm). In these cases, we show the limited options on the relevant product page to prevent confusion. We also do our Aivee MP2 based builds in center lock only, just to keep inventory manageable. 

A good place to start is this video that we did a while ago. Bear in mind that when we do videos, it's basically "have an idea, turn on the cameras and go" so these aren't quite as produced as a GCN video. Please excuse that. With that done, the biggest thing to point out is that both center lock and 6 bolt hubs and rotors will work with your brakes. Yes, if you have disc brakes, you can use either format. The hub's rotor interface is only an attachment method between the hub and the rotor. So long as that rotor is delivered to the place where your brakes expect and want and need it to be, which both formats do, the brakes themselves don't care at all whether your hubs and rotor are 6 bolt or center lock. If need be, you can shim your rotors using either commonly available 6 bolt rotor shims or our super genius, exclusive center lock rotor shims. These allow you to set your rotor alignment precisely so that swapping wheels happens without any adjustment needed and no rotor rub. 

If you have center lock hubs, you can use 6 bolt rotors. There are adapters that are cheap, readily available, and effective. Many people are reluctant to change from 6 bolt to center lock hubs because they have a bunch of 6 bolt rotors hanging around that they don't want to turn into junk. Adapters make that a non-issue.

Centerlock rotors are typically a few dollars more than most 6 bolt rotors. That is because center lock rotors need to be 2 piece (there's an aluminum center part for the hub attachment and then a steel part for the actual business end of the rotor). The better 6 bolt rotors are also 2 piece, so they are the same cost. Two piece rotors seem to stay true and resist warping a little better, plus the aluminum does a good job of dissipating brake heat. 

Centerlock rotors are generally easier and more error proof to install. One simple lock ring versus 6 small bolts to get cross threaded or stripped or lost or whatever else happens to these things. 

We carry the appropriate rotors for any disc type anyone reading this is likely to have or need in the store, which again helps make it easy. The only critical thing you need to know is rotor diameter, which is printed on your existing rotors if you have them, or will be in your brake and/or bike specs. For almost everyone reading this, you have either 140 or 160mm rotors. Some of you will have 180s on your mountain bikes. If you do downhill, you might have bigger rotors. 

So the center lock versus 6 bolt debate is actually pretty straightforward. All else being equal, my personal preference is center lock, but once they're on and tuned, you really don't notice too much one way or the other. 

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In some parts of the web, when I go to purchase centerlock discs, I’m seeing interior- versus exterior-spline rotors. How do I know which I have on my bike?


Love this quick rundown! Thanks for putting it online. I’d try to buy stuff through you guys if I lived in the US.

John in Brisbane

Phil – You’re throwing a lot at me there – fat bike calipers, 29" forks, and 26" wheels – but yes, you easily be able to get them aligned. Hopefully the calipers are post mount because there’s about a 100% chance that that’s what your fork will come with.


So you’re saying that I should be able to adjust my old caliper to fit a new center lock disc? I am purchasing a new suspension fork and 29" wheel that has the center lock hub for my 26" fat bike. I’m hoping I can use the calipers that came with the fat bike.

Phil Karper

Regarding hub/rotor slop:

>Dave on August 11, 2018

>Andrew – Not normal. Zero movement is almost impossible to get, but 2 to 3 mm is wildly excessive. The nature of the interface is such that that would be hard to have happen. The hub’s splines must be really undersized.
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FINALLY, someone has acknowledged the existence and cause of this apparently common problem. I’ve test ridden several mid-range examples of Cannondale, Trek, Specialized, Giant, Scott and Parlee. All but one had the described rotor/hub slop. No mechanic has been able to attribute the slop to anything but pad movement. However, with rotor locked while I push forward, I can SEE the hub rotate very slightly.

Only the Parlee Altum with DT Swiss hubs did not exhibit this annoying trait.

Joe Siczpac

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