Autobus

Are ceramic ball bearing bottom brackets worth the extra expense? I don't know whether to believe the testimonials from pro riders paid to use them?

joshalope

If you have the money to spend... yes, otherwise, just train more.

mrfish

Analytically - At the bottom of the shopping list:
- How much of your power is lost in the bb? 3W? 1W? 0.5W?
- How many watts are dissipated by wearing cycling gloves, carrying 2 bottles not one, unzipping zersey 2" etc?
- How many watts could you gain by committing to do a training program on a regular basis?
- How many watts could you save by hiring an expert to help you riding round the velodrome in different postions and download your results on an SRM?

So unless your life means time <<<<< money, or you're about to represent your country, keep the money or spend it on things higher up the list.

jamiewilson3

Are they hype?

No - they do have a measurable benefit
Yes - it is a small benefit and very expensive (and internal, so they add no bling)

headlessspider

will they last longer than cup/cone or cartridge bearing bbs?

whitemax

Interesting. I'd like to hear more on this subject. Just got the most recent Excel catalog and on the back cover it has a number of ceramic bearing items for sale like for the DA bottom bracket and Kysyrium wheelset. Seems like bearings for the wheels would be the better of the two but I wonder if any out there have tried them yet.

joshalope

The practicality about the "efficiency" of ceramic is that first, you're talking about fractions of a watt. Second, at speed, the sheer force (read: torque) that's going through the bottom bracket is enough so that forward inertia/momentum compensates for any loss of power due to friction. In fact, I think most of the friction savings is due to the fluid the bearings are in, not so much the bearings themselves. Where it really matters is when riding slowly, i.e. during climbing, because any momentum is lost to gravity. Rasmussen is apparantly a ceramic fanatic which makes sense in that he specializes in climbing. He even went to ceramic bearings on his rear derailleur pulley wheels. As for durability, it's probably not as good as traditional bearings because as far as I know, the ceramic stuff isn't serviceable.

headlessspider

all i know about ceramic balls is that they're as hard or harder than the equivalent steel ball and they're a lot lighter. i do not know if they would last longer running on steel races or if they're running on ceramic races.

joshalope

I'm pretty sure they run on steel (or perhaps some sort of alloy) races. The whole point of ceramic bearings themselves, is that during the manufacturing process (which is long and expensive), they are able to make a bearing that is for all intents and purposes, perfectly spherical, as opposed to the dimensional imperfections of their steel counterparts.

waterrockets 

Actually, any friction in the bearings dissipated kinetic energy as heat, so that energy is lost. It's an especially consistent loss on a bottom bracket because your cadence is pretty regular (compared to hubs which vary in RPM wildly with speed).

Don't get me wrong -- it's still a very minor difference, but speed doesn't effect it like power and cadence do. I can't imagine anyone could perceive the difference on the bike.

dbduke

the original use was in machinery. They allow equipment to spin at higher RPMs than could with previous bearings. This I believe is mostly due to the lower weight. I think durability comes into play to, but I never read anything on the industrial side of things that led credit to how useful they may be in a bicycle. Perhaps someone could point out some more info on the subject.

headlessspider

+ 1 i also read that nice tidbit before. boca has full ceramic bearings but i do not know if they have ones for the bicycle bb. but according to their site it should last a lot longer than the standard ball bearings. i'm not really sure if i should believe the marketing stuff but i'd like to know if anyone has any experience with the durability although i would doubt that very much since these things are relatively new. i'm really more interested in the ceramic balls lasting longer than them making my bike lighter or spending 3 watts less...

merlinextraligh

Velonews did some testing, which indicated the difference is under 1 watt. Admittedly, their test protocol left open room for quibbling.

The interesting aspect of the Velonews testing was that External bearing BB's have more friction than conventional internal BB's, and that you have to put ceramic bearings in the external BB's to get them close to the External BB's friction wise.

So the takeaway would be that the best way to decrease friction loss, (and keep money in your pocket) would be to run a conventional square taper, or ISIS BB with steel bearings.

merlinextraligh

Ok, as I read this I was looking for an emotiv Icon Perhaps or or or or even

When I saw none, I could only think of the words of John Mac Enroe: "you cannot be serious" Even if you took all the hype of FSA or Zipp, or any other ceramic bearing manufacturer as gospel, your talking about a couple of watts, and a MPH difference measured in hundredths not even tenths. It's even less difference than the rolling resistence difference between different clincher tire brands.

Your statement is like saying "when I road with Continental GP 4000's I could only ride 60 miles, but now with Michelin Pro Races they roll so much I easier I can do 100 miles." I'd suggest ther are othe factors at work.

merlinextraligh

Any data?

You cant possibly believe they reduce your effort 40%

I'm presuming you have at least one other set of wheels, without ceramic bearings. Are you claiming you can do a century with your good wheels, but only a metric with your other wheels?

Have you ever done a TT with the ceramic bearings and compared it to your time without ceramic bearings? My guess is there would be little or no difference (except maybe from the benefit of confidence.)

I just put Zipp 303 tubulars on my bike. They feel a lot faster, I'd like to say my sprint speed went up 2mph because they spin up so easy, and they do feel faster. If I didn't think about it analytically, read anything about it, or objectively measure it, I might be able to convince myself that it's true. But if you do look at it analytically, do measure it, it isn't true, and its not productive to claim things as true that are scientifically impossible, simply on the basis "I've ridden them".

DZA_LA

When i was wearing my Adidas I could only walk 4 city blocks. Now that I have my Jordans I can walk 8 city blocks AND jump 4 inche higher.

jamiewilson3

Their use in machinery had nothing to do with weight. It was a function of the added roundness (less friction loss and heat generated & higher heat resistance).

Yes, they should last longer than standard bearings (cartridge & loose ball). But you can buy a crap load of replacement standard bearings for 1 set of ceramics.

waterrockets 

There's just not room for that much improvement in hub bearings. Unloaded, my front wheel will rock until the valve stem and rim seam are balanced, which may take 2 or 3 minutes. There's no way you can feel any improvement on that amount of friction.

merlinextraligh

I think waterocket's point, if I understand it correctly is that there is so little friction loss in a hub that will spin freely for 2-3 minutes, that even if you eliminated that friction completely it wouldn't be meaningful to bike performance.

So even if your hub would spin for hours, it just wouldn't make that much difference.

IIRC Velonews's testing put the gain from going to all ceramic bearings on the bike at less than a watt. 1 watt is not going to change your bike speed in any measurable sense, and it's certainly not going to increase your endurance 40%.

Zipp, who charges a boat load to sell some cat's ass silicon nitrate ceramic bearings, claims that their ceramic bearings save 0.8-1.0 watts, which they claim is 2-3 seconds over a 40k TT.


Now if Zipp, who get's about a $1,000 premium for it's Zed tech wheels, claims they're worth about 0.01 mph, what makes you think your American Classic bearings are a 40% improvement?

Psimet2001 

Ceramic bearings are "better" than steel bearings.
They will last longer and experience less friction.
They are much better at handling high speed and high temperature applications than steel bearings.
High speed and high temp - cycling is not.
Ceramics are so much more expensive than steel - if the prices were closer we wouldn't be talking about this....

The issue is not whether or not ceramics are better, but rather are they worth it for cycling applications. With regards to 99.9% of the riders my answer would be "no."

What would be more of a benefit would be if someone were to retrofit the existing external BB cups with better steel bearing cartridges. The ones in use utilize contact seals and heavy grease. This is due to the fact that they are meant for high speed motor applications...not cycling specific applications.

Anyone with an arbor press, some specific tools (available through Phil Wood for one), and a bearing catalog could make their own BB exhibit less friction while sticking with steel bearings. They wouldn't be sealed as well, but if you already have the tools then who cares. You could swap 10 sets before you would even be close to the price of ceramics.

Before I switched jobs I was thinking about doing this upgrade for people out of my home shop. Still might if all the marketing people stick with ceramics as the only upgrade.

Let's face it...cyclists are a bunch of consumers that will spend 20 hours searching the internet to save $20. They just refuse to pay $1 more for anything that they can't justify as "being worth it" performance wise. Talk about an untapped market for a "cheaper-than-ceramic" option......

joshalope

Uh, not to be offensive here, but I think you should look at that graph again. It looks more like around 4 minutes 10 seconds to me (assuming you started at 1:13). The speed line drops off at about 5 minutes 25 seconds. Also, without any conclusive data to support it (i.e. experimental and control groups), like the others, I find it obscenely difficult to believe the power gains you are claiming are real. Perhaps a little bit is the placebo effect, but if you're going from 60 mile to 100 miles rides, you are definitely increasing in strength, not enjoying the benefits of only a mechanical gain. A guy who can ride 100 miles on an entry level road bike, can ride 100 miles on a top of the line, handmade, ultralight, Italian bike, with all the latest components, that was blessed with holy water by the Pope.

joshalope

The bottom line, to answer the OP's question, is that the cost:benefit ratio of ceramic bearings for a cycling application is ludicrous, and I'm not talking about ludicrous speed and going plaid.

joshalope

But the speed drops off completely. How do you interpolate the rest of the data? Not having sensitivity below 2mph seems like either the mark of an imprecise instrument, or in fact that wheel did stop at that time. The fact that we need explanation of the information further proves there's a lack of conclusive, scientific data to support you claim.

(Also, please don't think I'm chewing into you, it's pretty hard to convey inflection over the ol' interweb, no offense meant from my end)

joshalope

Have you tried the same experiment on a wheel with regular, non-ceramic bearings (but still high-quality) and then compared the data?

DocRay

Facts:
they are harder
they are rounder
they are lighter
they do not corrode

But guys who can't afford them will make up anything to dismiss them.