ceramic bearings - any real advantage at all?

neeb
neeb Posts: 4,470
edited September 2009 in Road buying advice
Almost anyone with any apparent engineering knowledge claims that any performance advantage from ceramic bearings will be so small as to be practically non-existent, maybe about 1W or something. This makes a lot of sense when you think about the tiny amount of effort it takes to spin a wheel or a crank without a chain when normal bearings are installed. And yet a lot of people say they can feel a difference in practice. Is this just 100% placebo effect or could there be something that the skeptics haven't accounted for?

Could there be an advantage for avoiding weird clicks etc. from the bottom bracket because of the greater durability and higher precision of high quality ceramic bearings?

Comments

  • incog24
    incog24 Posts: 549
    They're useful in jet engines, but possibly not the most cost effective upgrade on a bike.
    Racing for Fluid Fin Race Team in 2012 - www.fluidfin.co.uk
  • cougie
    cougie Posts: 22,512
    Placebo I reckon.
  • Monty Dog
    Monty Dog Posts: 20,614
    My only experience is with inline speed skates where you use 16 at a time - they do 'roll' marginally better but it's the different noise that attracts people, a bit like the rumble of a carbon disc wheel. IME to work well they need to be clean and lubed with a light oil - sometimes difficult to achieve with many bike applications. IMO there's no point in spending hundreds on bearings and running a dirty chain and and worn chainrings / sprockets.
    Make mine an Italian, with Campagnolo on the side..
  • clanton
    clanton Posts: 1,289
    If they last longer - in other words longer by at least the same factor that they cost more than the regular options, then I may be interested.
  • maybe for a pro in a time trial where marginal improvements can add up to make a real difference

    but for pro's riding in a group or regular amateur stuff no advantage whatsoever
    'dont forget lads, one evertonian is worth twenty kopites'
  • if i was using loose bearings on anything, which i'm not, i'd stick a single ceramic ball in just to keep everything clean.
  • Spending the same amount to change your chain more often will likely make more difference. I can feel the difference with ceramics but have no delusions that a pair of lycra overshoes makes more difference to speed...
  • juggler
    juggler Posts: 262
    No measurable benefit... I think they degrade a nit slower... Not sure on that one, either ways for us mere mortals no difference . Have ceramic bb on one bike and non ceramic on another an can't tell any differenrce. DT Swiss non cramic hubs on the latter and can not imagine anything better.
  • neeb
    neeb Posts: 4,470
    Pretty much what I thought. I'm changing the bearings in my chorus ultratorque BB and ordered the cult ceramic ones on an impulse purchase... :oops: Maybe I've wasted the money but it'll be interesting to see if they last any longer without issues.

    One thing that just occurred to me though - clearly any difference in resistance caused by friction is tiny in relation to pedaling forces if you are comparing how easily a crank spins forwards under forces applied only in that direction. But when you are pedaling you are also applying strong lateral forces to the crank, effectively compressing the bearings. This compression is uneven, so that (I assume) the bottom part of the bearing is being compressed while the top part is being subjected to negative compression. Is it possible that this creates substantially more friction in a steel bearing (that is more compressible and also made to less tight tolerances) than in a ceramic one, and that this could be a much more significant source of friction in real-life situations than simple calculations of how the bearings perform in ideal situations might indicate?

    I'm sure this sort of thing will be bread & butter to anyone trained in engineering, which I'm certainly not...
  • samb01
    samb01 Posts: 130
    Zipp lead engineer Josh Poertner shares some thoughts on ceramic bearings:
    http://nyvelocity.com/content/equipment ... h-poertner
  • neeb
    neeb Posts: 4,470
    Zipp lead engineer Josh Poertner shares some thoughts on ceramic bearings:
    http://nyvelocity.com/content/equipment ... h-poertner
    Confirms what I've read elsewhere that it's the quality of the bearing that counts more than whether it's steel or ceramic, so I'm glad at least that I went for the cult ones that Campagnolo themselves put in Super Record. The test will be what they are running like in 2 years time...