Pinkbike Poll: Center Lock or 6-Bolt Brake Rotor Mounting?
The mountain bike industry is full of standards, and thankfully they've been pared down from years ago when the hacksaw had to come out in order to fit a brake caliper or chain guide, but for decades now, there have been two mounting methods to fix a rotor to a hub.
Before you get too up in arms about the 200 and 203mm rotors size difference (even though that's a very valid reason for frustration), let's just take a minute to remember there used to be more than just two rotor mount options. Brands like Cannondale and Hope made hubs in the late 90s that featured four bolt hub and rotors, and then, when Shimano introduced Center Lock, the original Saint hubs used an oversize hub 47mm spline for the matching rotor to sit on, larger than the 35mm Center Lock size that the rest of the models used.
At least today, there are just the two options; 6-bolt and the 35mm Center Lock systems. But why still have both? I've heard and understood arguments for both.
Chris King decided to limit manufacturing to just Center Lock hubs during the pandemic due to production capacity constraints. They've since returned to producing both options after receiving massive demand for the 6-bolt option.
In a cross-country race scenario, where a rotor may need to be changed on the fly, then Center Lock may be faster to change. The required tool isn't the most convenient item to pack in a day bag and you certainly won't find one at your local hardware store.
I've also run into issues with the Center Lock ring coming loose and causing the hub bearings to bind when torqued to the recommended setting. On the other hand, removing stripped T25 bolts can be annoying and time-consuming.
Weight wise, they aren't lighter either, at least in the 220mm size. SRAM's HS2 rotors weigh 305.5g for the Center Lock version and 271.6g for the 6-bolt, both fastener types included.
Project 321's 6-Lock hubs allows for either mounting method using just one hub shell. It is an extremely clever design, but should we even need two standards? You can catch more on the highlights of the Project 321 6-Lock hub from Sea Otter 2023 here. Maybe they should rebrand the company to Project 241.
If you just one one brake rotor mounting style, what would it be?
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Minha GT Sanction tem roda para treino e roda para corrida, DT swiss 240 e Shimano zee, ambos center Lock com rotor icetech Freeza 203mm
Eu tenho somente um disco de freio e compartilho ele em ambas as rodas, é 1/6 do tempo de troca comparado com o 6 parafusos
Using a park tool BB wrench both rotors are off in seconds versus the slow process of 6 bolts twice.
The armament HS2s are stupid heavy so I use DT Swiss adapters and 6 bolt rotors.
Crazy talk but it’s faster, lighter, and versatile
Good wheels are like 1000$. Good rotors are like 200. I don't get why anyone would go through the aggravation of aligning rotors to change wheels. Install em set em up so they are ready to swap. Then your wheel changes take 5 minutes not 45 minutes of flashlights and caliper aligning
as your own mechanic it the quickest too.
the only time you are lost is changing rotor in a middle of a ride - but hows going to do that any way.
the only reason to use 6 hole is an exposure of old fashion stubbornness or lack of manufacturing technology.
same applies to chainrings on cranks
generally modern technology is a progress concluding previous mistakes or simple improvement.
same as we don't get stuck on 26" wheeled solid bike or V brakes or mechanical shifting or Nokia 5010 we should progress to progress in all levels.
Don't let hacks touch your bike?
Also, if there is a thread issue, inserts are an option (if the hub has enough meat for repair) for the traditional version
It's not like someone gives you 40 wheels and rotors at once.
Old: 135x10qr, 135x12, 150x12, with 100x9 or 110x20 front.
Mid: 135x10qr, 142x12, 157x12 with 100x15 added in on the front.
Current: 141qr boost, 148 boost, 157 super boost, 157dh, with 110x20 boost added on the front.
Yeah it's confusing, I'm a complete bike nerd (in case you couldn't tell haha) and I only just grasp it all and the differences between them all, the bottom line is, each jump has been a significant improvement (the 3.5mm recesses were a big step forward, and were usually convertible with different end caps, and boost has made wheels (especially 29ers) a lot more durable because of the wider flanges. To some degree the fault is in the old standards being still available and used in some capacity, and the fact it was incremental changes not a big jump forwards (ironically, that's what super boost was supposed to be, basically the logical end point instead of a stepping stone). What I usually say to people is, don't worry too much, just get boost and remember that so if you need wheels you just go for boost wheels, which are pretty much the most common standard these days, have to search around a bit for a 142 or 150dh wheel set these days.
Okay. This is literally the reason why Centerlock is the worst. If you're swapping wheels, nothing every lines up just right. There are microshims you can run behind 6 bolt rotors to make sure your rotors set up exactly the same at the caliper regardless of which hub/wheel you're running.
Centerlock has no such adjustment.
I just use 3-bolts triangulated. Best of both worlds, way lighter too!
Each standard has equal advantages and disadvantages - I think they come out even. I wouldn't (and haven't) avoided a wheelset because it meant I would have to change rotor standards. I also haven't had the opportunity to choose between JUST rotor standards for otherwise identical wheelsets.
For a road bike, Centerlock looks cleaner, especially with the smaller rotors. So if only one standard had to survive, for all disc brake bikes, it would be Centerlock. But functionally, there's no clear winner.
For what it's worth, my mountain bikes are all 6-bolt, and I chose 6-bolt in the poll. I like the simplicity, like you, and I don't swap wheels these days. But I don't think it's bad to have both options in the market. As far as I know, Centerlock isn't killing people.
You're right that Centerlock CAN have all of those issues, and that 6-bolt doesn't. But Centerlock has things people might want, that 6-bolt can't provide: quicker, easier swaps, universal compatibility, and yes, cleaner looks (at least with the internal spline lockrings for road bikes). And in reality, most people don't and won't have an issue with Centerlock. There should be a follow-up poll to see what % of people have.
I wonder why Pinkbike is running this poll in the first place. They tend to pose a question like this right before a relevant new product comes out.
The way a v-brake locks a wheel is brutal, indifferent, and viscerally satisfying. Trickstuff could never.
V BRAKES 4 LYFE
As I mentioned elsewhere, I don't mind either standard but the fastener types leave a bit to be desired. I've also never had a CL lockring come loose after proper install.
Granted, most of the CL rotors I see are on road bikes.
I would bet serious cash that no one in the history of the sport has won an event because they removed 30 grams from their setup.
Stripped 6 bolt? Chuck a helicoil in and forget it ever bothered you.
For riders i don't think there is enough of a difference to matter.
@L0rdTom: The extent to which the braking force is transferred to the face of the hub's rotor flange, is determined by how much static friction the rotor can apply to the hub because of bolt tension. I'm sure it's not nothing, but I doubt that it's 100% of the torque either. I guess for science somebody should enlarge the holes in a 6-bolt rotor, install it with the holes centered over the hub holes, properly torque the bolts, then do some hard braking and see if it moves!
I've said it before and I'll say it again, but I still don't get why bike mechanics are so opposed to power tools. Little 12V impact driver would make that such a short job.
TL
However, I once had a centerlock disc come lose during a ride and it was a major bummer. If there was a better tightening system I would happily go centerlock. As it is I usually leave some knuckle skin on my spokes everytime I try to loosen my overtight rotor with a centerlock tool.
Centerlock does seem "easier", if you're installing/removing your rotors all the time (like if you travel by air/put your bike in a travel bag frequently).
But the downside of "I can't fix it with a multi-tool on the side of the trail" is something that bothers me more. Also, I can check/fix 6 bolt rotor tightness problems while the wheel is on the bike.
All said, I prefer 6 bolt, but its not a huge deal. Just if I'm buying wheels or hubs, its going to be 6 bolt. But if a bike came with centerlock, or I was given centerlock wheels for free, I'd keep them.
..and better
I'm lost at how it is even better?
Am I missing something?
Literally does the same job...
You might not actually just be an elite human that never has problems in life and other people genuinely have problems with products that you've not? Haha!
And after a while the splines were knackered!
More disposable parts in an industry already obsessed with throw away parts.
I must also say that a lot of multi-tools have a rotor-straightening slot (simply a rotor-wide slot) or come with pliers.
Just like 31.8 bars are 1 1/4”, 35mm are 1 3/8”, and the part for your grips is 7/8”
I don’t really prefer 6 bolt, but all my bikes have come with 6 bolt wheels so that’s the standard I’m sticking with. I did purchase a set of center lock wheels once because they were on sale really cheap. But then I used 6 bolt adapters rather than buying center lock rotors.
I can’t remember when I changed one out.
It is relatively common to have a spare (rear) wheel or wheelset for a specific type of riding, e.g. I have some old heavy bombproof wheels for the 2-3 times I go to the bike park in summer, others might have some light wheels for XC/marathon events.
If you only swap out a few times a year, it's not really worth having another pair of discs or cassette. Also the fact that we have 200, 203, 220 and 223mm as viable alternatives, with different widths.
You can also have idiots like myself who buy 4 galfer 223 discs to mount on main and spare wheelset, and then decided he didn't like them.
- zero mention of the fact that center lock hubs are lighter
- intentionally points out that 6 bolt rotors are lighter but cherry picks the heaviest possible design for the center lock rotor (taking a 6-bolt and effectively just adding an adapter.
A DT 240 center lock hubs is 17g lighter than the exact same 6 bolt hub.
Pick a rotor where they actually put an ounce of design effort into the center lock version (example - centerline X) and it's a 17g difference.
So no, 6 bolt isn't heavier unless you're cherry picking parts to feed your bias.
Only acceptable discussion is the one bolt vs 6 when changing rotors and can/cannot repair with a multitool, but both systems work well enough 99,99% of the time, that trailside repairs are an absolute non-issue with both if used correctly.
- Both work well enough. Individual use cases drive the preference in most cases.
- My biggest beef with either is the fastener. Despite what some say about torx heads, it's amazing how easy you can blow out a rotor bolt if you're not paying enough attention. A deeper and/or socket head or a hex bolt would be better imo. With CL, unless you have a 12mm axle and the internal spline lockring using the cassette tool, the external spline lockring can have tool engagement issues. Akin to T47 bb with so little material to engage. In both cases the quality of your tools can make things better, but neither set up is perfect.
- I have both on personal bikes, and the only problem I've had is blowing out a torx head rotor bolt. Luckily I was able to mandhandle it out by abusing some tools. But that can happen to any bolt on your bike if not enough care is taken or the wrong tool is in play, I don't blame it on the rotor attachment style. As I said, they should move to better fasteners.
Centerlock rotors exist because Shimano was cautious about the physics of rotor bolts loosening in the six-bolt design. Centerlock rotors use a spline mount and a lock ring to make installation easier and faster.
Centerlock rotors have several advantages over six-bolt rotors, including:
Less risk of loosening
Less risk of damaging the hub
Lighter
Less prone to bending
Takes up less hub space
Easier to center
Easier to remove
However, centerlock rotors are generally more expensive than six-bolt rotors, which can be manufactured anywhere in the world. A pair of Shimano centerlock rotors can cost between $40 and $90, while a top centerlock rotor can cost between $35 and $200
2. Nobody is carrying a spare rotor on rides, so you are down a brake even if you can remove it. Just take the brake off with your multitool instead of the rotor and you are in effectively the same position.
Performance/convenience wise I see no difference, but when traveling it is much easier to take off a CL than a 6B
From an engineers standpoint as I’m also a Design Engineer, tolerances have to be much tighter and it has to be torqued properly, once that is done it can sustain higher loads due to interlocking of the sequencing pins.
2. Did you install them with a torque wrench?
3. If so, how long since it was calibrated?
I've never had a rotor that I installed (hundreds at least, since it's my job) come loose. I use a beam torque wrench, which is calibrated every time I use it (you just look at the gauge and make sure it's at zero under no load).
I guess even with correct torque, CL does stand a chance of loosening if the tolerances between the hub and rotor are poor, AND the rider does a lot of fakie (backwards) braking. Quality parts will prevent this issue--the amount of play between a good CL rotor and a good hub is negligible.
If bolts were better, splines wouldn’t exist.
Anyone who’s done home electrical work knows that tightening a box to conduit connector is possible with a flat head screwdriver and hammer, but just today I saw a tiny tool that does it better. And that same design could easily be made into a bike multitool. I shoii yo I’d start working on that actually.
2. Be a dick about it ✅
We can go more specific, on not just what we like more on boyth standards, there is a bit more behind.
Center Lock : Low Hub Flange.
@wobblegoblin: WT packwrench is light and has 8mm hex option for pedals
I have had a few bolts come loose on 6-bolt and I didn’t even notice until next service.
… and is an actual pain in the ass to deal with
Mountain bike (and gravel with fork) = 6-bolt.
We don’t need two.
A drill set to low torque setting and tightening by hand makes sense. An impact? We installing car wheels or bike wheels?
Dude, you seriously think I’m talking about a 500FtLb impact tool?
Let me spoon feed it to you- looks like a 1/4” drill, holds the same 1/4” tool bits like you’d see as a Philips tip for a cheap tool set.
It spins fast but with low torque. Low enough not to do damage.
But go ahead and do the final torque with your drill “slip” clutches. I’m doing the final tightening with my inch/Lb wrench.
Any questions?
Learn names of things before throwing the snark around. Especially when you repeat my comment basically.
I use a 12v drill to do my rotors. I use tools every single day. Don't get all pissy when you don't even bother to read the next line.
You need to learn names of tools, start by reading the tool! My impact says “impact” right on it!!
It takes a tiny battery pack, and would have trouble driving a screw deep into a piece of wood.
Snark is immediately assuming someone is stupid enough to use a tool for driving lug nuts over 100FtLbs for 6 tiny fasteners into a hub.
You start throwing stuff like this around and some 13 year old grabs an impact driver and immediately takes the heads off the bolts.
Adjustable torque on an impact doesn't exist, as far as I know. The very nature of the tool is to max out its torque and then act akin to a hammer drill just in a smaller package. An anvil hits the chuck and creates the patented ugga ugga creating more torque.
A Milwaukee 18v is rated to 750ftlbs and 1100ftlbs removal, other brands are similar, that was just the first Google result. The only time that's useful on a bicycle is removing pedals or cranks after hex keys failed and before you get the breaker bar.
Also take a breath, this is no way to behave. Your mother would be embarrassed. Did she buy you your Fischer price "impact" drill and that's why you're getting so worked up?
“Untgrad, what about the children!?!?!”
..this conversation is over
en.wikipedia.org/wiki/Impact_wrench
@Untgrad and @Blownoutrides and myself are talking about an impact DRIVER. Good for driving screws into timber/drywall and small bolts that you'd find, say, holding on the brake rotor of a bike.
en.wikipedia.org/wiki/Impact_driver
An impact wrench is called an impact driver here.
I'll challenge anyone to swap a center lock rotor system faster than a good mechanic can with a drill, I'll have the rotors swapped before you find your BB tool and clean the blood from your knuckles.
Not that it should matter, but I'm a bike mechanic of 20+ years, shop, OEM, team, you name it. All my bikes are 6 bolt, yes I've owned CL, and yes they came loose, rattled and were annoying in general.