AttieSlabbert Posted June 21, 2007 Posted June 21, 2007 I've been asked this question a few times. This is the advantages of using ceramic bearings in your hubs, BB and derailleur pulleys.I will post 2 posts- 1) the advantages of all ceramic bearings, 2) A comparison between FSA Ceramic Bearings and Token Tiramic Bearings. Advantages of ceramics: 60% Lighter Than Steel, 2-1/2 Times Harder Than Steel, No Oxidation, Better Surface FinishLess Heat Development Increased Rigidity Less Vibration No Galvanic CurrentLow surface roughness More Durable - Last 5-10 times longer than steel Not prone to contamination. Ceramic balls are antimagnetic and electrically non-conductive ceramic bearings require less power (watts) to move Very Low Friction - Ceramic balls are rounder and smoother than steel Very resistant to dirt and dustVery stiff balls which make for a more stiff wheel/bottom bracket Higher tolerance What does all this mean to you and me?TESTING DATATests by SKF, and confirmed by the Danish cycle magazine Cykel Magasinet (Sept 2005), describe dramatic reductions in friction compared to conventional cycle bearings. For example:With a pair of race wheels (total of six bearings), friction with ceramic bearings is reduced 22 fold, While Dura Ace pulleys consume 0.78W @ 500rpm, ceramic pulleys use less than 0.06W. A Record BB @ 100rpm and 400W consumes 0.6W, the same BB with ceramic bearings consumes 0.02WCeramic bearings in your bike's bottom bracket will shave 1-2 seconds per KM. In a 40k time trial that is 40-80 seconds of free time gain! Ceramic bearings in your bike's wheels will shave even more time.Tests by the Danish magazine Cykel-Motion (March 2005) and subsequently supported by calculation, show how using ceramic bearings can reduce rolling resistance by 50%, saving 22m in just 55 seconds at 32kph. In short, astounding speed improvement of 4%.So, it comes as no surprise to learn that top professional riders are using ceramic bearings to win major races The results are great, riders are convinced. The math explains it. The friction reduction of ceramic bearings aids a wide variety of riders. The advantage of ceramic units is greater at lower speeds. From a technical point of view, riders sheltered inside the peleton or riding off road have more to gain with ceramic bearings. Comparison: Token & FSA :
AttieSlabbert Posted June 21, 2007 Author Posted June 21, 2007 Characteristics of Token and FSA Ceramic Bearings Token FSA Composition: Si3N4 Ceramic Balls sameDensity = 3.2 g/cm3 vs 7.9 for steel 3.2 g/cm3Vickers Hardness (HV10) = 1700 Kg/mm2 vs 700 for steel -- 1600 Kg/mm2 Bending Strength: 828Mpa ???Compressive strength: 3500Mpa ???Resistance: 1014Ω.Cm ???Tiramic? Bearings are more resistant to corrosion (up to 10x longer according to the salt spray test) because of the Titanium coating.TOKEN uses Titanium coated bearing races & cones and FSA uses steel racessolid Ceramic Balls, unlike most of the other large companies who only use SUJ2 cones. Small price!!!!!!!!!!! Very Big Price!!!!!!!!!!!!!! I hope this answers a lot of questions!!Any more questions - feel free to contact me.
Spinnekop Posted June 21, 2007 Posted June 21, 2007 So what is the small price??? The suspence is killing mehttp://s3.amazonaws.com/advrider/drums.gif
Thug Posted June 21, 2007 Posted June 21, 2007 There is an article in the latest Mountain Bike Action entitled "Ceramics Bearings 101" They did some interviews and this is what they say.... American Classic's Bill Shook - "For us it's an upgrade option. At $199.95 to upgrade the 6 bearings in an AC hubset to ceramics is very expensive. We use ABEC 5 rated bearings with ceramic balls and stainless races. You do get something out of the ceramic upgrade. The riders swear they can tell the difference" Shimano's Kevin Wilson - "Shimano still isn't convinced that the benefit will ever surpass the cost pitfall for most riders" Chris Cocalias founder of Titus - "I replaced the stock Titus Racer X steel bearings with ceramics. After three rides the bearings were shot. I've never had a pivot wear out as fast as that" No Tubes' Stan Koziatec - "No matter how good you make the bearings, the moisture will still get in there. Two years ago we tried ceramic ball with standard races. The riders tore them up after only a few weeks. It wasn't even worth the bother" So judging by the above, the jury is still out on ceramic balls/bearings.
AttieSlabbert Posted June 21, 2007 Author Posted June 21, 2007 Well - he said 2 years ago! A lot has happened in the bike industry in 2 years. A few years ago some "people in the know" said carbon is just a passing fancy and will never be be used on a big scale to make more than a few components. I can think of a few reasons why bearings are shot after only a few rides:not the right size, installed incorrectly, inferior seals, races and cones.Like the guy said- no matter how good the bearings, the moisture will get in there- so why use balls that will corrode in a short time and not balls that will last 10x longer? And standard races with ceramics?! No wonder!!If shimano is not convinced- it means that the difference is there- but how do you convince someone who doesn't want to be convinced - for whatever reason? I don't know.Price - well yes - US$199 is a lot!! Like I said you can compare the above between FSA and Token and decide where the differences are. Token has the upgrade option on wheelsets for about US$75.A lot HAS happened in 2 years!!
AttieSlabbert Posted June 21, 2007 Author Posted June 21, 2007 If you buy the Token Wheelset the difference in price between normal sealed bearings and tiramic bearings is about US$75. FSA- I've seen on the net prices from US$130 to US$180.
dirtrider Posted June 21, 2007 Posted June 21, 2007 Not enough has happened in 2 years to run out and go ceramic me think . The price still does not justify the upgrade . But why buy bearing from LBS in the first place ? You can get the same spec bearing in your choice of material at your local BEaring Man for less 50% and more .
AttieSlabbert Posted June 21, 2007 Author Posted June 21, 2007 Well if you can do that -- go for it! Why not? Maybe that is what the guys did whose upgrades only lasted 3 rides. Support your local Bearing Man. What do you have to lose? The tests I mentioned earlier was done by guys with nothing to gain or lose and you can't argue with numbers. When your legs are tired - you can argue and keep pushing harder- that's perception. But 2+2 = 4 and that is a cold hard numered fact. And 2 years is a long time in design and industry- think about power meters, HRM, carbon, Titanium, tube shapes for being aero, bike weights, etc. You have to think 3 years ahead to stay WITH the pack!
Johan Bornman Posted June 22, 2007 Posted June 22, 2007 Dear Attie Ceramic bearings aren't all they're cut out to be. Yes they're harder, but now they're destroying their softer (steel) races very quickly. Hubs are more expensive to replace than bearing balls. Yes they're lighter than steel but the saving on 38 balls is less than the weight of a strand of spaghetti. Let's get realistic. Bicycle wheels spin relatively slowly compared to hard disks and turbo chargers, where ceramic works nicely. There is no heat build-up in bicycle wheels. Ridgidity - just hardness in this case, see point one. Anti-magnetic? Who cares. Good mechanics keep their balls togher with a magnet and retrieve stray bearings with magnets. Imagine loosing a R20 bearing ball and a magnet can't find it! Everything is prone to contamination. Dirt doesn't care what the ball is made of. Galvanic current. C'mon... lets get real. The rest of the "benefits" is just hardness and polish repackaged. 50% reduction in rolling resistance? Not so, most of a wheel's rolling resistance comes from the tyre. The bearing's rolling resistance is so small, that a 50% reduction is meaningless and cannot be measured over any reasonanble race. I don't for a minute believe these benefits cited here. A bike is not a turbocharger. Steel is just fine. JB
AttieSlabbert Posted June 22, 2007 Author Posted June 22, 2007 HI Johan,I agree with some things you said- I mean galvanic current? Magnetics?And hey - if Felt can say that their behind the crank brake calipers will help you corner faster because of a lower centre of gravity, then why not mention stuff like magnetics and currents. But with the hardness and the softer steel races- true -- that is why Token uses Titanium coated races. Weight saving- cyclists spend hundreds of rands to save 5g - 10 g on a derailleur or a handlebar or pedals. So a strand of spaghetti will make a difference to them. Unlike aerodynamics - the resistance is "high" no matter if you're going slow or fast. I've heard people saying that it actually increases the slower you go. The difference can be measured that is why I posted the test results above. There is definitely heat build up in bike wheels and, no, you cannot compare it to turbo chargers or stuff like that. These wheels are powered by human muscles not electricity so a small difference makes a big difference. So you cannot compare these tests to tests done on turbo chargers and their benefits. Like you said a bike is not a turbo charger!! You have to pedal it!! I didn't do the tests - you can go to www.fullspeedahead.com/fly.aspx?layout=product&taxid=420www.fullspeedahead.com/downloads/Ceramic_InsertBook.pdfand www.velocarbon.com/ceramicbearings.html for their results. Cyclists do feel the difference and the difference can be measured so - there IS a difference. Is the difference enough? That is for you to decide. Is it cost effective - that is the personal part of it - is buying a carbon frame cost effective? ? ? Is paying hundreds or is that thousands of rands more to upgrade to dura ace or campy to save a few grams - worth it? You tell me. Attie
Johan Bornman Posted June 23, 2007 Posted June 23, 2007 Attie, if you can say that you can feel a 2 gram force (which is what the ceramic bearings save) on you whilst cycling, well who am I to argue. I am familiar with the FSA studies and they are masters at marketing non-existent benefits. Titanium is softer than steel, so it is a very very poor choice of bearing race material. I smell a marketing rat. I know what cyclists spend to save weight, I see it every day of my life. I, that's me, think they should study some elementary physics and then figure out what the benefits of those savings really are. But that's their money, not mine. Some people pay for water that comes in a bottle. Who am I to say they're not rational? Your definition of "high" resistance is slightly skewed. Wind resistance is high - 90% of your energy gets consumed by overcoming wind resistance at 40kph and almost 100% at speeds exceeding that. Bearing resistance is extremely low by comparison. We're talking grams vs kilograms. If you can feel it, be my guest. RegardsJB
AttieSlabbert Posted June 23, 2007 Author Posted June 23, 2007 Hi Johan,I had a few people asking me about ceramics so I thought I'll do a search on the internet and see what tests have been done. This is what I've found and I just compared it to the bearings that I have the information of. I'm not saying I can feel the difference. I'm saying that there is a difference and it can be measured according to the studies/ tests done. And for some paople if there is a difference - how minute it might be- they want to use it or get it. So - high or low is not the point - the fact that there is a difference and that it was measured - is my point. Is it big enough to make a difference ? Some will say yes - some no. Will a handlebar that is 20g lighter make a difference when climbing a hill? Personally - I think no - others will argue with me to the death. So - I'm saying that it looks like there is a difference - but is it big enough? That is what every cyclist has to answer for him/herself. CheersAttie
Christie Posted June 23, 2007 Posted June 23, 2007 There is a definite advantage to ceramic bearings. The lower rolling resistance, durability etc. has been proven by science. Do Zipps high end Z-series wheels not have Ceramic bearings? The question most cyclists will ask is: Will it make me faster? That is a hard question to answer. Friction in the hubs and bb make up a very small % of the total energy loss on a bike. Even if ceramic bearings cut this friction in half, half a gain of a small energy loss is still small. But on the other hand, this is a saving in energy that you can buy, without any cost to your body (unless your wife does not approve of the expense). A small saving in energy becomes more significant as the time over which it is saved increase. I would not upgrage my normal race wheels to ceramic bearings. Over 100 km races I typically do, I would not bother, and Im not someone who has to have the best of the best of everything. If I had a TT bike, I would think about putting ceramics in its wheelset. If I were doing Ironman, I would definitely get ceramic bearings.
AttieSlabbert Posted June 24, 2007 Author Posted June 24, 2007 Hi Johan,"Titanium is softer than steel, so it is a very very poor choice of bearing race material. " Yes - you are right, it is softer than steel. Apparently one of the reasons titanium is used for the races with the ceramic balls is exactly that ! The harder it is the more brittle it becomes. That is the problem. Because the balls are harder and if you use a metal / alloy that is also very hard (steel) - it might break more easily when you hit a pothole or something very hard. So to compensate for that - they tried something else. And because titanium has excellent anti-corrosive properties, it was chosen. It made a difference and it was measured and to say that there is no difference or no advantage to using it, you have to take on the guys who did the tests- like FSA and the German and Belgium magazines. They posted the results and the numbers and like I said earlier you cannot argue with numbers from a fair test. About the non-existent benefits from FSA, you have to tell that to the 10+ Pro Teams in the TdF using FSA parts. If it makes them faster, there must be some benefit for the normal guy on the bike. And that is up to the guy ON the bike to decide. CheersAttie
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