What's the benefit of center lock rotors?

Light weight is the advantage but loosening and movement are common problems.

Or is there always inherent rock?

No, not several mm, maybe 1 or 2 on some floating rotors (between carrier and braking surface), should be no rock between centrelock splines, dunno what convertors you have, they may add some clearances.

Riding the SDW on Saturday, and the rear lock ring (which WAS tight) is now loose, causing the rotor to rattle wildly… Sigh..!

It probably wasn't tight, or you've over tightened it/cross threaded it and damaged the thread or the adaptor. Or maybe the adaptor is rubbish.

The benefit is one tool, one fixing, so it's easier to not make a mess of, easier to fit in the factory, makes the hub lighter, probably makes little difference to machining complexity (all those little teeth are fiddly to do). Also should be easier to keep it flat (as it's not dependant on 6 fixings on the same flat surface all being tightened evenly). Doesn't mean much though, all the most warped discs i've had have been centrelock...

Rocking shouldn't be an issue as you only brake in one direction (unless you're Danny Macaskill). I own both types and can't say I've had issues with either

The rocking forwards and backwards is probably the pads in the caliper rather than the disc.

I thought there was meant to be something about tolerances and repeatability - and therefore better cross compatibility and set up.

Six bolt setup can, but must, cater for everything from beautifully machined floating rotors to stamped steel - I doubt the disk is reliably in the same place every time

If you set up the calliper every time you change wheels this is not a problem, but for a TdF mechanic on the roadside.

All driven by roadies allegedly.

To be fair I had the same from 6 bolt rotors once. The little bolts loosened enough for them to rock/knock.

Obviously my fault but quickly resolved on the trail.

Riding the SDW on Saturday, and the rear lock ring (which WAS tight) is now loose, causing the rotor to rattle wildly

No worries, I guess you whipped out your centrelock tool and nipped it up, right? Oh, hang on...

The only advantage is it's one tool for BB and disks and thats about it imho.

Also, who remembers the days of taking a hyper racket  cassette tool in your massive saddle bag on a ride.  That would sort your issue on the trail.

I thought it was just having one thing to tighten and loosen and not six.

The only advantage is it’s one tool for BB and disks and thats about it imho.

AFAIK there's even variants of the CL lock ring that need different tools, so the chances of the tool that fits your lock ring being one of several options that might fit your BB are slim, even less if it's not HT2.

The discs do rotate ever so slightly on the centerlock spines, but this is only an issue if you brake when the bike is rolling backwards. I've never had any other issues with them, they seem fine, but then so do 6 bolt rotors.

I've always thought the 6 bolt to centerlock adapters looks a bit flimsy, but I don't think any of the issue you describe can be attributed to them.

Benefits (to me) are that it's easier to remove/refit the discs if you travel with the bike a lot.

I'm sure there are also benefits to the manufacturer in the initial assembly process, but they don't affect me.

I've gone to centre lock on all my bikes just because it's easier to remove/refit rotors - not that I do that very often.

They can't fall off and or 100% fail like a 6-bolt can AKA idiots protected from their own stupidity.

But, not all centrelock rotors/hubs/lockrings are the same as there's no actual standard...

Marginally easier in the garage, way harder out on a ride.  I'm a no

hyper racket  cassette tool

I still have my Pamir Hyper-Cracker, I think it’s in a box with my Cool Tool, a massive headset spanner and some cone spanners.

Quicker for UCI World Cup mechanics during wheel changes.

Are there benefits?

Not that I can see.

Also know what you mean about movement. It's not much at the hub, but that gets amplified with larger rotors.

Obviously my fault but quickly resolved on the trail.

And that's the point.

Personally, I won't buy centre lock hubs.

I have two sets of centre lock wheels because they came with bikes. However when I had some new wheels built, I specified 6 bolt hubs. No particular problems with centre lock just felt more normal for me. Oh, and you can usually get 6 bolt discs much cheaper.

The advantage is faster installation for the manufacturer of bikes at the factory. I think that is why they were made.

Also faster disc swaps, but that won't be an issue for any normal users.

The benefit is one tool

Best tell Marin that - they fitted two different sizes on my bike, plus I've now got a different BB in there so need two different BB tools and a long spline cassette tool. 🙄

Hard to round the lock nut on a centre lock whereas I've had quite a few second hand bikes/wheels that have needed a rotor bolt drilling out from a 6 bolt hub. So I prefer centre lock for that reason

They're better as they're easier to fit or remove without rounding a bolt, but worse because its much more annoying to fix on a far flung bike ride somewhere. I haven't felt any real tangible benefits.

Weirdly, my gravel bike forks seem to only take centre-lock rotors. Sounds like I am mistyping there, but I am not - if I fit a 6-bolt rotor, the bolts rub against the post mounts on the brakes.

Annoying thing to find out after getting a new set of wheels...I have had to use the flat bolts from an adapter to secure them which are even easier to round the head on.

It shouldn't rock? It's the same as 6-bolt, the bolts / lock-ring just apply the clamping force, it's friction that keeps the rotor still. None of mine move at all.  If you've got back and forth rock with the brake on it's the pads in the caliper which is normal.

The benefit is on the assembly line you can build the wheels with one action with an impact driver, not 6 small easily cross-threaded ones. To the end user there are no benefits.

They’re better as they’re easier to fit or remove without rounding a bolt

I can't say I've ever successfully rounded a torx bolt.

Don't think there was much use of discs in pro racing when centrelock came in, so doubt that was a reason for adoption?

I don't mind them as i've never had an issue with them. Never had a 6 bolt or centrelock come loose. But I never carry a bb tool or cassette lock ring around, so that is an issue for trail maintence! Yes, centrelock rotors are usually more expensive, but the wheelsets are often cheaper, so perhaps it's swings and roundabouts on that?

If it's not the pads moving, then the adapter type may be an issue, though probably not. Some adapters rely on the bolts acting as studs for the rotor to sit on, while others like shimano use 6 tiny bolts to secure to the adapter ring. Doubt that would create the movement though...

I like them. They work well for me, it also gives us an opportunity for endless discussion. Centrelock or Centerlock?

If your centre lock rotors are moving on the splined mount on the hubs, they're not installed correctly or either the hub or rotor is knackered. Or if you're using adapters, the interface between the disc and adapter is knackered. I'm pretty certain they're meant to be done up to 40Nm, just like cassettes, so bloody tight!

They existed in MTB long before road bikes went to disc, so don't go blaming the roadies.

AFAIK there’s even variants of the CL lock ring that need different tools, so the chances of the tool that fits your lock ring being one of several options that might fit your BB are slim, even less if it’s not HT2.

Well, TBH, it's a shimano standard, so you either use a shimano cassette tool, or a shimano bottom bracket tool...

I thought there was meant to be something about tolerances and repeatability – and therefore better cross compatibility and set up.

Six bolt setup can, but must, cater for everything from beautifully machined floating rotors to stamped steel – I doubt the disk is reliably in the same place every time

Nope, there's no standard offset for centrelock or 6 bolt. unless you use the same model disc and hub everywhere. I've even got shimano hubs with shimano discs where the rotors are in sufficiently different places that the disc rubs slightly (until you've done a few stops). Saying that, some of my 6 bolts, the different wheelsets you can't even get the disc into the caliper.

Rounded and/or snapped rotor bolts used to be a fairly regular thread on this forum and I've seen a few myself when working on other folks bikes. Through accident rather than design, most of my wheels are Centerlock, but then I'm also a fan of Shimano hubs.

FWIW, none of my rotors rock.

Seems to be a mixed bag response!

Anyway, the rocking ISN'T the pads - it's certainly wither the splines, or (more likely) poor tolerance in the CL->6b adapter.
Anyway, i'm sure some proper CL rotors will fix that.

Also, "Personally, I won’t buy centre lock hubs.".. I agree, and my 'big bike' has 6 bolt i( hubs, but the Hunt carbon wheels ONLY come in centrelock!

Oh well!

DrP

steve_b77

Free Member

If your centre lock rotors are moving on the splined mount on the hubs, they’re not installed correctly or either the hub or rotor is knackered.

I've seen it on multiple wheels on multiple bikes, both straight from the factory and shop/self maintained. And with torques checked with a torque wrench.

Eg brand new DT factory wheels with brand new Shimano rotors. Took them off, checked everything, retorqued, still doing it. But definitely not the only one. My RS4s with brand new rotors do it as well. I've also seen it with Shimano hubs and rotors.

Maybe it's an 'opposite ends of tolerances' issue, or something else, but I'd very much disagree with your 'presented as absolute fact' statement.

If you can tighten a CL lockring to 40Nm and the spline interface still rocks, it's almost certainly faulty. The end load at 40Nm is massive, the rotor will be clamped "very firmly".

I'd suspect that it's not tightened down onto the rotor itself, the thread has bottomed out somewhere.

I've got both. I don't really care, but I seem to find that there's less difference between hubs/wheels for the rotor position with CL, which is useful if you swap wheels from time to time.

You can get lock rings in fancy anodised colours. That seems a big plus.

From an engineering point of view - centrelock is shit!

The high torque rating required over quite a narrow area/limited number of threads is asking a lot of the aluminium hub shell (and lock ring).

The splined tool interface is another crap part of it - the design was fine for steel HG cassette lockrings but not for the aluminium material of a CL lockrings.

If the thread is damaged due to the above then it's new hub time - at least a damaged 6bolt thread can be helicoil repaired.

In its favour CL is easier/quicker to assemble.

Many freehub bodies of all standards run the same or similar sized threads and require similar torque without issue.

I have both CL and 6B on different bikes, and prefer CL.

On the point above about reaching end of a thread, I think that's a valid one. There could be issues with the depth of the spline interface sometimes. Just got a new CL wheelset myself, and the issue I had was the rotor was too far inboard...and had to use a cassette spacer to bring it outboard a mm, as the calipers were at the end of their adjustment too, and I couldn't centre the rotor. So that probably a hub manufacture thing. So definitely a combination of tolerances issue too perhaps...

Also, who remembers the days of taking a hyper racket  cassette too

I still take a HyperCracker with me when touring. I've never had a cassette lock ring come loose when riding but then I'd never had a wheel completely detension and need a roadside rebuild until tandem touring in Spain a few weeks ago...

Luckily I had my trusty Spokey with me...

I've run Centrelock for years, always torque'd them up to 40Nm as etched on the lock rings, never had an issue, even as a big lad running 203mm rotors.

YMMV but in my experience, so long as you follow the instructions it's a lighter, faster to install and remove system.

It's nearly universal for higher end road/gravel disc brake bikes now so I suspect we'd better get used to it, it's not going anywhere.

I suspect we're more likely to get an infuriating third standard than we are to see everyone agreeing on 6-B vs Centrelock.....

.....no SRAM, don't even think about it I know Centrelock is a Shimano creation but.. NO!

A whole article on centrelock here

https://escapecollective.com/threaded-17-centerlock-rotor-lockring-things/

(May be paywalled but I think you get a few free articles)

Your all wrong.

The benefit of centrelock rotors is there is now two disc standards that have to be accounted for meaning more profits for the share holders!

Rotors were the last part on a bike to have just one universal standard that worked fine. This just wasn't acceptable to the bike industry.

To be more serious I'm seeing a lot of new bikes now come with centrelock rotors instead of six bolt so there's obviously some benefit/reason for the manufacturer.

Rotors were the last part on a bike to have just one universal standard

4 bolt rotors anyone?

Hope also did 3 bolt rotors and started off with a super clunky spline on adaptor that accepted a 5 bolt rotor. The spline on adaptor was also super wide inc its locking, so non-drive flange was pushed way inboard. The worst of all approaches.

Easier to assemble on a production line