Carbon Ceramic Rotors?

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  • Carbon Ceramic Rotors?
  • Premier Icon njee20
    Subscriber

    We done this yet? Clicky.

    My instinct says these will be shite for mountain biking as they won’t work properly cold, what do we reckon!?

    Prices are really pretty reasonable if you get in on their Kickstarter funding – $170 for a pair, shipped. Half tempted as they’ll look proper pimp, even if they’re barely any lighter than KCNC!

    Saw those as well, interesting. Would like some real life reports first. As you say not that much in it weight wise, but boy are they bling!

    brakes
    Member

    I don’t really go in for bling, but I reckon they would be awesome.
    The article seems to suggest that the temperature of the rotor doesn’t impact braking performance.
    It does hint at noise though – one of my biggest gripes is noisy brakes so I’d worry about that.

    mtbmatt
    Member

    F1 carbon brakes need about 800 degrees to start working, but those on production cars must need to work from cold. So maybe it is possible if they can work at all temperatures.

    compositepro
    Member

    mr magura knows lots about this shit

    Premier Icon seven
    Subscriber

    I’d be more worried about crunching it on rock. Can’t see me being able to bend it back with a spanner:)

    Be good for Road bikes if the trend to road disks actually takes off

    jonstanley
    Member

    [url=http://singletrackworld.com/forum/topic/carbon-ceramic-rotors#post-4373921 wrote:

    mtbmatt[/url]]F1 carbon brakes need about 800 degrees to start working, but those on production cars must need to work from cold. So maybe it is possible if they can work at all temperatures.

    Because F1 brakes (and also airy-plane brakes) are made from carbon-carbon and need some temperature to work optimally.

    Production high-performance cars use carbon-ceramic, of many sorts. However making MTB discs from same materials would cost a grand-and-a-bit a piece. Kettle seem to have found a way to make a similar disc without costing a fortune.

    Whilst I don’t disagree with the fact they can handle a heck of a lot of heat and be warp free… I’m curious how good they will be to impact resistance. Oh… and how well they’d survive on a tandem bike with a team weight of say 400lb in hilly terrain. :mrgreen:

    brakes
    Member

    mr magura knows lots about this shit

    is he involved?

    avdave2
    Member

    njee20 be honest you only want them to help you be first on the forum to have spent a million on bikes. ๐Ÿ™‚

    Premier Icon njee20
    Subscriber

    They’re cheaper than ICEtech ones…

    compositepro
    Member

    is he involved?

    no hes a clever engineer guy from finland got hold of some stuff made some stuff and put all the myths to bed

    Kettle seem to have found a way to make a similar disc without costing a fortune.

    yup 20 quid and a company down south gets you the (sic) same thing..maybe if you all club together till theres 10 of you you can just pay the 200 quid and get your existing rotors wear resisted

    Premier Icon njee20
    Subscriber

    yup 20 quid and a company down south gets you the (sic) same thing..maybe if you all club together till theres 10 of you you can just pay the 200 quid and get your existing rotors wear resisted

    Again, in English? ๐Ÿ˜•

    smiff
    Member

    i don’t understand something. they say the rotor doesn’t get hot (is not a good heat sink like steel?). when you brake all your kinetic energy basically turns into heat. that’s what brakes do. if the rotor ain’t heating up, where’s the heat going? back into the brake caliper/hose? not good?

    sl2000
    Member

    @smiff: I’m assuming the article got specific heat capacity and thermal conductivity mixed up; and I assumed they meant that the conductivity is high (so the heat’s conducted away to the frame) and the specific heat capacity is low (so it doesn’t remain hot). I’ve no idea if that’s true.

    Premier Icon D0NK
    Subscriber

    even if they’re barely any lighter than KCNC!

    which ones? Have used the airotors and I’m not happy with the braking.

    get your existing rotors wear resisted

    eh?

    Premier Icon njee20
    Subscriber

    KCNC Razors are light (58g for a 140 IIRC), but braking isn’t quite on par with heavier ones I agree. Fine on the back.

    PaulD
    Member

    Very interesting video about making the rotor….but no mention of the specific brake pad.

    Overall a solution for endurance car racing where steel brakes need changing 3-6 times in a 24-hour race and high-load aerospace requirements, but inappropriate for MTBs.

    Very poor friction when cold and an unknown wear rate when soaked in abrasive slurry.

    Expensive and very bling, but I will stick with XTR callipers and KCNC rotors.

    ‘Stans’ did an aluminium rotor and special pads…are they still available?

    PaulD

    Premier Icon JAG
    Subscriber

    I have experience of Carbon Ceramic brake rotors – I design them for a large vehicle manufacturer 8)

    IF these are similar technology then the only real advantage is in weight reduction. But;

    1) they will work from cold
    2) they are susceptible to mud and water contamination which can reduce the friction between pad and rotor
    3) they are easily damaged by stone impact
    4) they do make more noise than Iron brakes on Cars
    5)they radiate heat rather than conduct as the specific heat capacity of the material is double that of Iron but the rate of conductivity is much lower
    6) they need very careful bedding in to get the best performance

    In my opinion the slight weight reduction isn’t worth the potential hassle but some people will get them just for the bling factor – this analysis also applies to Carbon Ceramic brakes on cars.

    Premier Icon njee20
    Subscriber

    Very interesting video about making the rotor….but no mention of the specific brake pad.

    The article says they’re designed to work with any pads, so it doesn’t matter.

    Can’t say impact resistance has ever occurred to me regarding rotors! Number 2 is a fair point without any holes to clear crap off the surface!

    brakes
    Member

    maybe you’ve just never noticed the impacts because the steel rotors haven’t been damaged by them.

    if I’m really honest, I like them because they’re black and not shiny metal. I try to minimise chrome/ silver stuff on my bike so these would be great ๐Ÿ˜ณ

    Premier Icon njee20
    Subscriber

    It’s just not a very exposed area though is it? I’d have thought you’d have to be bloody unlucky to suffer impact damage there!

    But yes, mainly they look pimp!

    andyl
    Member

    I had a quick scan of the article and got very confused by what they were saying about heat (and I do thermal analysis of composites).

    My own thoughts, backed up by what JAG wrote above, is that they have a high specific heat capacity and low conduction so compared to metal:

    a: it takes more energy to raise the temperature of the material in contact with the disc by 1 deg

    b: the lower thermal conduction means that a higher proportion of heat dissipates from the surface via convection (air) and radiation instead of conducting through the material

    I expect there is a lower CTE of these too?

    I quite like them despite obvious concerns. The spider looks like a moulded bit of recycled carbon fibres in resin.

    I’d like to see more about the flexibility and wear characteristics. JAG – any chance of a factory tour or more information? Never really looked into carbom ceramic materials but I have some ideas for using it in other applications (I’m a research collaborator for a large University composites group and work closely with manufacturing)

    stumpy01
    Member

    njee20 – Member
    It’s just not a very exposed area though is it? I’d have thought you’d have to be bloody unlucky to suffer impact damage there!

    My concern would be when wheels are taken off & bike chucked the back of the car with wheels leaning up against each other.
    Stainless can take a bit of flex, whereas I imagine that these would be very stiff & brittle.

    bwaarp
    Member

    It’s just not a very exposed area though is it? I’d have thought you’d have to be bloody unlucky to suffer impact damage there!

    You possibly don’t ride hard enough or rocky enough terrain. That or you’re the definition of a smooth rider. What size rotors do you run?

    On rocky loose trails you will ding your rotors.

    andyl
    Member

    is a way they might be better as metal rotors are easy to bend permanently compared to carbon/glass epoxy composites. No experience of carbon ceramics though.

    Premier Icon Northwind
    Subscriber

    You never know, the rotors might turn out to be more resistant to damage- steel ones are pretty delicate after all.

    (not to contradict JAG’s observations, he’s obviously better informed than I am but obviously car disks are a pretty different kettle of fish to bike discs, in terms of impact durability)

    Premier Icon njee20
    Subscriber

    What size rotors do you run?

    160/140, and don’t generally ride rocky trails it must be said!

    Premier Icon JAG
    Subscriber

    This is all about car systems but should be similar to the bike rotors.

    The car rotors I deal with are Carbon-Fibre re-enforced but with short, chopped strand fibres.

    The bike rotors in that article appear to show a woven Carbon Fibre material which will make them a bit tougher.

    But they are hard and inflexible and they will chip like any Ceramic material. Silicon Carbide is about third in hardness tables, not far behind Diamond. It’s very rare in nature and tends to be found in meteorite craters ๐Ÿ˜ฏ

    Small chips in the rotor are tolerable but there are strict limits. Anything over a certain size will write-off the rotor.

    Wear – is a tricky issue. On a car you have to remove the disc and weigh it to figure out if it’s worn out as they don’t get thinner like Iron discs do. However they do last about 3-5 times as long as an equivalent rotor on a car.

    CTE – Co-efficient of Thermal Expansion is much lower than Iron. About a third, so less distortion with heat. Therefore less risk of dragging or rubbing on the pads ‘off-brake’ if you get them hot.

    Last thing – car systems use special pad materials with these rotors.

    smiff
    Member

    i think the brittleness will make this pretty bad for MTBs, where rotors are very exposed and stones and sticks get thrown in all the time. nice for racers/people with money to burn or surrey hills riders maybe? :p

    btw, is there any part that can’t be made from carbon composites? bolts? tyres? :p

    Premier Icon Northwind
    Subscriber

    Thing is, a decent sized rock strike can write off a steel one too. Brittleness vs bendiness, be interesting to see how it all works out.

    You can get carbon bolts btw ๐Ÿ˜‰

    Premier Icon Northwind
    Subscriber

    <double post bug>

    smiff
    Member

    rocks sure, but you could write off one of these with just a little stone or gravel, i bet. or throwing the bike down badly. i’ll stick with my heavy steel thanks ๐Ÿ™‚
    and i’d never seen carbon bolts are they any good?

    Premier Icon Northwind
    Subscriber

    No idea tbh! I’m a weight weenie but I’m not that much of a weight weenie!

    compositepro
    Member

    Andyl

    i though one of your miniature nanoworld folks had done a single crystal …or something along those lines version of CFRSic that was for super duper applications

    the rotor centre looks forged as in hexmc type ..but then again squeeze any carbon between two mould plates and it looks similar

    Premier Icon Nobby
    Subscriber

    I like them, that is all.

    Premier Icon njee20
    Subscriber

    and i’d never seen carbon bolts are they any good?

    No, shocking! Only for ‘low stress’ areas like bottle cages, so much like aluminium, they’re not much lighter, and something like โ‚ฌ15 per bolt!

    messiah
    Member

    Wow, lots of folk have bought into this: they wanted $15,000 and have nearly $60,000 pledged with five days to go.

    Looks like a great way to fund a project… although perhaps not as TV friendly as Draggons Den.

    juan
    Member

    I’d have thought you’d have to be bloody unlucky to suffer impact damage there!

    Looks like you have answer your own question yourself ๐Ÿ˜‰

    messiah
    Member

    Carbon Ceramic Rotor as a cutting disc.

    Delivery of these has started… proof and pudding time soon for the kickstarters.

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