A few years ago Spanish motorcycle company Alpha got a bit of a resurrection and at the same time made the transition also into e-bikes. That crossover brought some unconventional solutions for their core two-wheeled vehicles, but also led to some more out of the box thinking that yielded something cool for us cyclists. Alpha now has what they say is the lightest ceramic disc brake rotor available. From just 32g for the 140mm carbon ceramic rotor, there’s no arguing that the Ceramic Rotor RS can shave some weight off your bike, but the real question is how it performs? Well, together with ceramic brake pads Alpha claims that it outperforms steel rotors and is rated from road & cross, all the way up to DH & even trials…


The rotors are manufactured in Spain using what Alpha calls the latest ceramic polymer technology. The result is claims of better heat management, improved braking in both wet and dry conditions, long wearing, and of course super light weight. This isn’t the first time we’ve seen carbon/ceramic rotors, but while we hadn’t tried those from Scappa, our first impression from the Kettle ones wasn’t so confidence inspiring. Alpha claims new tech that offers improved performance, so we are waiting and hoping to learn more.


The single thickness, unvented 6-bolt rotors are a fairly thick at 1.9mm, making them possibly a tight fit with some of the brake setups out there. (1.5-1.8mm is what you typically see in stainless steel rotors.) To get that full road, cyclocross, XC, enduro, DH & trials functionality, they start out small at 140mm and grow up to 203mm. The one trick may be that they claim to need ceramic disc brake pads, which Alpha doesn’t really elaborate on.

We asked for more info and they tell us that they are referring to organic-ceramic pads which contain ceramic fibers. The thinking here is that you don’t want any metal fibers like you would find in semi-metallic or sintered pads, which would damage the carbon ceramic surface of the rotors. We have seen from other carbon rotors that you needed metallic pads as organic ones didn’t last very long, so it would be interesting to see how these last.

alpha_ceramic-rotor-rs_carbon-ceramic-bicycle-disc-brake-rotor_140mm-rotor alpha_ceramic-rotor-rs_carbon-ceramic-bicycle-disc-brake-rotor_160mm-rotor

alpha_ceramic-rotor-rs_carbon-ceramic-bicycle-disc-brake-rotor_180mm-rotor alpha_ceramic-rotor-rs_carbon-ceramic-bicycle-disc-brake-rotor_203mm-rotor

The rotors aren’t cheap at 102-120€ a piece, but in an early start of Black Friday sales, they’ve dropped the prices by up to 45%. That means you can get a 140mm rotor for just 56€, the 160mm for 67€, 180mm for 74€ & 203mm for 98€. They are certainly light though. On Alpha’s own scales they come in at 32g for 140mm, 40g for 160mm, 56g for 180mm  & 69g for 203mm ones. Who is going to give them a try, maybe we’ll have to…?


  1. Complete and utter nonsense. Take something that works brilliantly such as a metal disc then make it from carbon fibre and claim it is somewhat better. So how does carbon weave wear down without fibres fraying how does it manage heat? Carbon rims are terrible for braking now they want the same level of crap with disc brakes. Only in the bike industry would somebody entertain this junk. And no carbon discs on race cars are not the same type of carbon

      • Carbon disc brakes are used on many type of racke Carboneing cars and racing motorcycles. The temperatures they can sustain are well in excess of what steel rotors and their pads can handle. I built a set of rotors in 1998 using phenolic based resins and carbon ceramic carbon base material and these were superb, The calipers needed to be widened to accoodate a 2.4mm rotor but I ran out of cash and disc brakes weren’t exactly vogue back then. A wider caliper needs to nearly 1.5x stronger than a caliper just 0.5mm narrower due to the leverage. Also the brakes needed DoT5 (silicone based) due to the much higher viscocity index.
        But the performance promise is there. Carbon Ceramic Carbon brakes will out perform steel brakes for stopping power. Modulation is a bit of a black art though and formualtions of carbon ceramic matrix is closely guarded secrets amoung the manufacturers like carbone industrie and brembo

        • I am very interested in what you are saying, but can you perhaps clarify a few of these things? For instance: “A wider caliper needs to nearly 1.5x stronger than a caliper just 0.5mm narrower due to the leverage.” … “Also the brakes needed DoT5 (silicone based) due to the much higher viscocity index.” Are you talking about 1.5x stronger braking force, or the structural integrity of the caliper? Why was the higher viscosity index of Dot5 needed? Did the rotor material cause greater heat build up?

          And what is your take on these ones?

          • The kettle systems seems closer to how race car disc rotors are made. Sounds good on the surface but the truth is only known once you ride them. Braking consistency is challenging because unlike steel where expansion is known and consistent across a batch carbon ceramic rotors and pads are a little less consistent.

            To go back to my need for a stronger caliper it was simply because the rotor was thicker and therefore the caliper pistons needed to be further apart to accommodate the rotor and allow it sufficient running space. But also the rotor and pads expanded more toward each other which increase the force trying to break the caliper apart. So the caliper needs to be stiffer and stronger.

            The dot 5 was too allow more consistent braking. The composite rotor and pads generated about 50degrees C more heat. Dot 4 or 5.1 would start to get very hot and added to inconsistent feel.
            I needed a ton more money to develop the brakes. Just didn’t have it and the company I worked for wasn’t interested because it wasn’t core business

        • wondering hiw stopping power can be better. its already at the effortless, instant wheel lock on both mtb and road..

          the issue is that mtbs deal with a different velocity from cars. we have large wheels and slower speed, thus need for more heat conduction, not less. plus a lot of the braking is done at 20mph speeds and less, not 65 and more.

          that makes it very hard to make good carbon rotors for bikes. and the real advantages wouldnt be modulation or power but staying true and lower noise

        • The comments thread won’t let me reply to your reply, two messages down, but I just wanted to say thanks for that great info you shared on your project. CCC rotors have always seemed so promising, but there is often little explanation for why they don’t work out in practice.

  2. Lud·dite – ˈlədˌīt/ – noun
    a member of any of the bands of English workers who destroyed machinery, especially in cotton and woolen mills, that they believed was threatening their jobs (1811–16).

    * a person opposed to increased industrialization or new technology.
    * “a small-minded Luddite resisting progress”

    • Yes it is well proven with super high braking forces that generate enough heat to actually make them work (F1 and Motogp). If you look at motocross then you’ll see they are still on steel discs. Anyone remember when Top Gear tested an F1 car?
      Richard couldn’t generate enough speed to get enough heat to get it to brake!

      • Fred, this is a logical fallacy. F1 brakes require that much heat by design. The heat range that their brakes operate is based on the forces that are required to slow them down from high speeds. They use a blend of carbon and ceramic that works best when the cars are being driven at race speed, and there is for sure a proper blend that best fits the needs of a bicycle. Are they a good idea for bicycles? Most likely not.

        • A test rig’s pretty pointless if it can’t be ridden; there’s not even any pattern to that spoke lacing (some spokes are crosses at the hub, some aren’t)

          • It looks like they did a six spoke drive side and a twelve spoke brake side. Definitely weird, but he’s a hardcore weight weenie, and those guys like to operate right at the edge of breaking their bikes. I wonder how much torque he outputs to that 18 spoke single speed wheel.

          • I think that guy goes the by the handle SebK, and he is a private individual in the UK if memory serves, whereas this rotor seems to be from a Spanish moto/auto parts company that is looking to get into bikes. They’re probably unrelated, but that does look like the sort of “outside the box” builds he has shown.

    • Yes, as do several high end cars, but they are not just a chunk of standard 3k weave. They are closer to a rotor made out of a brake pad vs a rotor stamped out of a sheet of carbon.

    • F1 race cars use brake discs made of carbon-carbon, not carbon fiber as we know it. There’s a significant difference, and by “significant”, I mean huge. Coupled with carbon-carbon brake pads, the coefficient of friction is much higher than what can be attained with the materials used bicycle brakes.

      • Yurp. If you’ve ever handled carbon-carbon parts, you instantly realise it’s not CF as most people know it. In fact, the parts I handled we part of an F18 engine exhaust, which felt and looked more akin to black metal.

    • theres a big difference:
      f1 wheels turn are thousands of rpms and the disc heats up instantly. so you want something that does NOT conduct heat too easily and that does NOT bend. for example carbon-ceramic.

      bikes are pretty much the opposite. you need discs that heat up quickly (NOT pads, or oil, but rotors). and thats why carbon rotors are probably not a great idea on bikes… and why rim brakes on carbon wheels are a problem

      on the bright side im sure they’re super straight 😉

  3. Seeing as how every carbon bike rotor up to now has failed most miserably, I hope that Alpha is offering something that actually works, and well.

  4. I had some of those SiCCC (or whatever their name was) carbon ceramic rotors from a Kickstarter campaign a few years back. They flat out sucked. And the “warrantied” versions flat out sucked too. Not saying it can’t work, but solutions that work in one space aren’t always directly transferable to another. But they might be on the right track make this a combined rotor and pad solution.

    • It needs to be a rotor plus pad solution. And the formulation of both I discovered is absolutely critical. It takes a lot of r&d to get it working adequately

  5. What about the carbon cog on the drive side? Carbon teeth seem like a really great idea.

    Maybe the carbon disk doesn’t have to work well because the drive train will self destruct before you can build up enough speed to require brakes.

  6. 21st comment and I am surprised no one asked the obvious materials science question: Doesn’t carbon fiber absorb heat, and since this is why carbon clinchers have sometimes been prone to heat-related deformity, wouldn’t the same risk apply here? Or is this application of this material somehow different?

    • carbon rims deform because air pressure is forcing the rim beads/flanges apart. No internal stresses on a rotor braking surface, beyond thermal stress (which still might be significant).

    • They don’t absorb heat, exactly. The resins tend to insulate, while (as I understand it) carbon fibers are conductive down their length. You’ll get hot layers that won’t disperse, aka localized heating. So one spot will bend out and fail.

      • I’ll bet your question has been answered by MotoGP and high-end auto racing manufacturers that sell carbon rotors.

        And yes, I was one of the suckers for the Kettle rotor project. Thus any new entry to the carbon rotor market is going to have to be damn good right outta the chute or it’s toast.

  7. Without more information I think it’s a little early to either hail or condemn this product, but as usual, there are plenty of people willing to pass judgement without any direct experience using it. At various times I’ve been told that: 9 tooth cogs don’t work for a variety of reasons, gearhubs are horribly draggy, Di2 won’t work with a 9 tooth cog, you can’t fit a square taper Campy crank on a square taper Shimano bb… The list goes on. The two things that all of those people had in common was that they were all sure that they were right, and they were all proved WRONG in the real world. Before you decide that a thing will or won’t work it might be a good idea to try it and see…

    • 9tooth cogs won’t fit on a conventional freehub. All hail the XD driver. Still, 9tooth cogs have other disadvantages.
      From owning a Rohloff and trying to make it work for XC, I can tell you the drag is noticeable but not terrible.
      I don’t see why a 9tooth cog wouldn’t work on di2.
      You can fit a Campy crank onto a Shimano bottom bracket. It’s considered a “b” fit. The tapers are the same angle, but the Shimano taper starts off slightly bigger. For a given bb length, the crank will sit slightly more outboard. There is also less overlap of the crank and spindle. I’ve never seen a failure attributed to this, but there has to be a reason they overlap a particular amount.

  8. Component makers have to only recommend “optimum” performance and compatibility. They have to say it will not work since their brand image and performance is at stake. Yes things work which are rated at lower performance, however they do work for people who are willing to work within the new standard of fit and performance it was not designed for. Go talk to a pro team mechanic on making things work which are not supposed it. They have amazing stories to tell on this subject… especially in the early 90’s, 2000’s.

  9. I remember TruckerCo made carbon rotors. I remember seeing a couple of guys running them in 2014 or so.They worked poorly. I asked the rep about them at a race a while back and he said they could never make them work, something about not building up enough heat.

  10. Wow, weave is structural, resin (the ceramic compound that touches the pads in this case) provides the friction surface.

    Some people need to go watch YouTube vids on carbon lay up.

    The key is the resin mix, which will be different to every other out there.
    Forget the carbon bit.

    • The carbon lay up is important as the carbon tensile properties aren’t with temperature. The appropriate carbon with a suitable resin is one aspect. But then you need a friction material that doesn’t want to adhere to the resin. The whole system has to be considered for component harmony

  11. I would love to see some data and a real world long term review. Until then, I’ll stick with steel rotors and metal brake pads from truckerco that can be had for 10 bucks. Currently rocking shimano zee, xt icetech rotors, with 10 buck pads. Arguably the best brake performance money can buy no matter how much you spend. I’ll take a weight drop with carbon rotors but only if performance increases too. The proof is in the pudding. If they are making a better product, prove it. Tall order in the bike industry I know, but just maybe if the riding community insists on data before the purchase we’ll get it.

  12. I always thought the problem with carbon fiber braking was the resin. Carbon fiber is made under extreme heat just to get the molecules to align the way they do, the resin, not so much. Fix that and you are good i suppose. Although it still seems like a different orientation of the fibers themself might make more sense. That said, i go with the commenters above, F1 has already solved this problem.

  13. What about a Centerlock version. I would buy a rear just to try it but if I have to use an adaptor the weight gain would not be worth it.

      • Some people don’t like to think. 40g rotor + 30g ISO to CL adapter is still 50g lighter than the best centerlock 160mm rotors I’ve seen. That’s 100g combined, which in the weight weenie world is nothing to scoff at.

  14. nothing new to see here in terms of carbon discs.
    back in the day, remember that yeti penske carbon upside down carbon disc brake bike?
    everything returns! 😉

  15. The pics of the wheel used in the article were used by Bikerumor because they did the article with Sebs extreme bike which just happened to have the alphas on. I have them and have yet to fully test them but find it a pain that Aplha can’t recommend a specific make or pad. Organic-ceramic pad! And they do rub on my calipers due to their extra thickness.

  16. Carbon SiC brakes works just fine for bikes. Like 10-15 years ago, I made one out of a brake rotor from a F16, with pads specific for the material.
    Beats any steel rotor setup hands down.
    The cost is a bit prohibitive though, as I recall some $3000+.

  17. Had a catastrophic failure with this brake after a couple of minutes going downhill. The carbon layers on both rotors delaminated, then shredded trying to go through the calipers. Result – going downhill with no brakes.

  18. Ok mechanical engineer here: Let’s clear things up a bit.

    -First off, a quick look around forums reveals that these a prone to failure, which makes sense because this is not the way to make a carbon rotor. Bike Rumor, you guys have a responsibility to update these kinds of posts. Are you not concerned with the well being of your viewers?

    – Secondly, these are not at all related to F1 and MotoGP type brakes (Carbon Carbon). Their closest cousins in behaviour are carbon ceramic road brakes, as those found in supercars. Still far off, as those rotors require months of silicon carbide deposition in an oven, hence their cost prohibitive nature.

    The bottom line: These will work when cold, but not perfectly. They will work better with heat, but will delaminate (which makes me think that they are using regular epoxy resin with additives to enhance the bite and hardness, but nothing appropriate for the heat). Don’t buy these. Steer clear, no matter how much you’d like to save 120g.

  19. It has been six months since this article was written. i can say thst i wrote Alpha and got a quick reply, which is a good sign. muy question for anyone seeing this is heave yoy tried the Alpha rotor and if so, what brake pad do you use and how well do the alpha rotors work for you?

  20. Attention! Cauttion! Be carreful! I bought one of these rotor and even when respecting all the conditions of use it was destroyed after few kilometres. You will notice that there is no Phone on their web pages: impossible to contact them directly. When you claim the rotor they didn’t answer. You will receive no invoice, so no address of return is possible and you will not find it on the web pages. On top of that the paiement is not secured! All this is very very very strange and all this looks like as a big SCAM. If you want pictures of the destroyed rotor (disc) I can send it to anybody…

  21. I ordered, paid for but never received the two carbon/ceramic rotors from Alphamotocycletes. They answered my emails during the ordering process but when the rotors never arrived I was unable to get them to respond. I have a customer in Spain that I asked to look into this matter for me. He told me the same thing – the company just didn’t respond. My advice – don’t place any orders with this company

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