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Old 09-24-06, 11:29 PM   #1
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ceramic replacement bearing for shimano BBs...

is there such a thing.. do any of the FSA replacement bearing fit shimano dura ace external bearing bottom brackets?

and how good are the PhilWood replacement bearings in relation to the stock Dura-Ace bearings? do the PhillWood seals on the sealed bearings have less drag?
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Old 09-25-06, 05:04 AM   #2
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http://www.enduroforkseals.com/id101.html
http://www.peterverdonedesigns.com/b...ombrackets.htm

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Old 09-25-06, 05:30 AM   #3
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Try:

www.bocabearings.com
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Old 09-25-06, 07:10 AM   #4
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Now the question: what does it get you? Basically nothing. The resistance of bearing seals at the bottom bracket means next-to-zero in terms of resistance to your pedaling. There have been other threads on this. Save your money. Unless the Dura-Ace bearings are crapping out on you due to your hammering in a way that a pro sprinter could only dream of

Here's a recent and informative thread on the matter. And another, similar opinions but somewhat less informative.

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Old 09-25-06, 11:12 AM   #5
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Originally Posted by timcupery
Now the question: what does it get you? Basically nothing. The resistance of bearing seals at the bottom bracket means next-to-zero in terms of resistance to your pedaling. There have been other threads on this. Save your money. Unless the Dura-Ace bearings are crapping out on you due to your hammering in a way that a pro sprinter could only dream of

Here's a recent and informative thread on the matter. And another, similar opinions but somewhat less informative.
here is cyclingnew's review... with independant testing that shows significant (~4%) of total wattage difference... 4% is a pretty huge difference for swapping out 1 component. i have to work for a long time the get my FTP to raise by 4%. this article really made me sit up and take notice.

http://www.cyclingnews.com/tech/?id=...ws/FSA_MegaExo
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Old 09-25-06, 11:18 AM   #6
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Originally Posted by timcupery
Now the question: what does it get you? Basically nothing. The resistance of bearing seals at the bottom bracket means next-to-zero in terms of resistance to your pedaling. There have been other threads on this. Save your money. Unless the Dura-Ace bearings are crapping out on you due to your hammering in a way that a pro sprinter could only dream of
Right. Bearing drag of a moderately good steel bearing is basically zip, zero, zilch... it's utterly negligeable. Read the book "Bicycling Science" to see how little of a bike's resistance actually comes from the bearings, it's a fraction of a percent.

That means that even if the FSA bearings have half the rolling resistance of steel bearings--which would be incredible, since this is an engineering problem that has been refined for more than a century--it could only make a tiny fraction of a difference in your riding efficiency. There are a lot better ways to improve your bike for the $200 cost of the FSA bottom brackets
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Old 09-25-06, 01:14 PM   #7
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Originally Posted by moxfyre
Right. Bearing drag of a moderately good steel bearing is basically zip, zero, zilch... it's utterly negligeable. Read the book "Bicycling Science" to see how little of a bike's resistance actually comes from the bearings, it's a fraction of a percent.

That means that even if the FSA bearings have half the rolling resistance of steel bearings--which would be incredible, since this is an engineering problem that has been refined for more than a century--it could only make a tiny fraction of a difference in your riding efficiency. There are a lot better ways to improve your bike for the $200 cost of the FSA bottom brackets
take a look at the link above... don't know... maybe cyclingnews tester got duped, but i don't think so... they say the 4% reduction is on total Watts at condition x, y, z... and that campy square taper BBs have great friction numbers but the new external bearing BBs inspite of their great stiffness etc have terrible numbers in terms of friction... so you'd be right to say that replacing your super record or c record steel balls with ceramic would be a waste of time but it would seem the the same cannot be said of external bearing BBs.. anyway have a read.
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Old 09-25-06, 01:23 PM   #8
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i read the other threads and one of the comments was about friction from grease and it seems that the ceramic bearings could actually be run dry or with very light oil rather than viscous grease...
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Old 09-25-06, 01:33 PM   #9
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Originally Posted by doctorSpoc
take a look at the link above... don't know... maybe cyclingnews tester got duped, but i don't think so... they say the 4% reduction is on total Watts at condition x, y, z... and that campy square taper BBs have great friction numbers but the new external bearing BBs inspite of their great stiffness etc have terrible numbers in terms of friction... so you'd be right to say that replacing your super record or c record steel balls with ceramic would be a waste of time but it would seem the the same cannot be said of external bearing BBs.. anyway have a read.
Sorry, but that article just seems like dubious crap to me.

I have some questions about how the supposedly independent testing company actually did those test: notice that they don't give figures comparing the power loss of the bottom brackets alone (ceramic vs. steel bearings), but only for the total power loss of a road cyclist. The article blabs about how square-taper BBs supposedly have much less drag than external bearing BBs. I don't know if that true or not, but it still just DOESN'T ADD UP, for one simple reason: The bottom bracket drag does not constitute 4% of the total power loss of a road cyclist, therefore no amount of improvement in the bottom bracket drag can reduce the power loss by 4%!

I wish I had my copy of Bicycling Science with me, so I could give you some authoritative numbers. I'll try to dig it up. Computing the bearing drag isn't terribly hard. Basically, all you need to know is the frictional force of the bearings in a BB, the distance that they travel in each revolution of the BB, and the cadence of the cyclist. Then, the power dissipated is: Power (in Watts) = Force (in Newtons) * Distance (in Meters) * Cadence (in revolutions per second). The number I can't remember is the frictional force on the BB bearings... if anyone can come up with it, it will be very easy to estimate the power dissipated in the bearings.

If you read this (rather heated) thread about ceramic bearings on rec.bicycles.tech, you'll find some math about how to compute bearing drag and other frictional forces: http://groups.google.com/group/rec.b...bebb77708c53b8
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Old 09-25-06, 01:55 PM   #10
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Still haven't found any hard numbers on ball bearing friction... RRRGGH, but please read this: http://www.madsci.org/posts/archives...9243.Eg.r.html

From that post:
"Bicycle wheel bearings vary in design, but each wheel usually is fitted
with a pair of shielded and caged ball bearings, lubricated with a light
grease or heavy oil. Friction of such ball bearings is largely from
contact between the balls and their cages. Without cages, friction
results from ball-to-ball rubbing. The rolling friction of the balls to
support a load is small. Losses from the grease or oil are generally
small, excepting for speeds and temperatures that are uncommon in bicycles."

This contradicts TWO of the arguments for the FSA bearings: first that ceramic bearings perform better under load (the post indicates that frictional losses due to varying load are small), and secondly that losses from the viscous lubricant are significant (they are not at the speeds and temperatures in bikes).
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Old 09-25-06, 04:00 PM   #11
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Originally Posted by moxfyre
Still haven't found any hard numbers on ball bearing friction... RRRGGH, but please read this: http://www.madsci.org/posts/archives...9243.Eg.r.html

From that post:
"Bicycle wheel bearings vary in design, but each wheel usually is fitted
with a pair of shielded and caged ball bearings, lubricated with a light
grease or heavy oil. Friction of such ball bearings is largely from
contact between the balls and their cages. Without cages, friction
results from ball-to-ball rubbing. The rolling friction of the balls to
support a load is small. Losses from the grease or oil are generally
small, excepting for speeds and temperatures that are uncommon in bicycles."

This contradicts TWO of the arguments for the FSA bearings: first that ceramic bearings perform better under load (the post indicates that frictional losses due to varying load are small), and secondly that losses from the viscous lubricant are significant (they are not at the speeds and temperatures in bikes).
I visited the FSA booth at Frostbike last year and checked out their ceramic bearing offerings. They had two front wheels next to each other, one supposedly with ceramic bearings and the other without. The ceramic bearing wheel would definately spin longer, it was quite amazing. I'd never seen a wheel spin so long at such slow speeds. It's possible that they were using tricks like removing all the seals or something, I couldn't know. I do know that it was very impressive how long that wheel kept spinning. I won't argue with you about the mathmatics and science of it all because you'd win, but from what I've seen it is worth trying FSA's bearings. After all, when it comes to bicycles every bit counts. I also know that when a steel (non ceramic) wheel bearing is in rough shape it is noticable which would mean that bearing quality makes a difference. It seems to that whether or not is is worth the money is a personal/finacial decision, if you can afford it then go for it.
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Old 09-25-06, 04:07 PM   #12
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Originally Posted by Pete Hamer
I visited the FSA booth at Frostbike last year and checked out their ceramic bearing offerings. They had two front wheels next to each other, one supposedly with ceramic bearings and the other without. The ceramic bearing wheel would definately spin longer, it was quite amazing. I'd never seen a wheel spin so long at such slow speeds. It's possible that they were using tricks like removing all the seals or something, I couldn't know. I do know that it was very impressive how long that wheel kept spinning. I won't argue with you about the mathmatics and science of it all because you'd win, but from what I've seen it is worth trying FSA's bearings. After all, when it comes to bicycles every bit counts. I also know that when a steel (non ceramic) wheel bearing is in rough shape it is noticable which would mean that bearing quality makes a difference. It seems to that whether or not is is worth the money is a personal/finacial decision, if you can afford it then go for it.
Again, this is the a case where there is a calculable difference, and it might be quite large (2x, although I still find that a bit high), but the difference is still negligable compared to the total amount of wind resistance at any reasonable speed. I doubt that double-blinded testing with time trialists could show a statistically significant difference.
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Old 09-25-06, 04:15 PM   #13
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Quote:
Originally Posted by Pete Hamer
I visited the FSA booth at Frostbike last year and checked out their ceramic bearing offerings. They had two front wheels next to each other, one supposedly with ceramic bearings and the other without. The ceramic bearing wheel would definately spin longer, it was quite amazing. I'd never seen a wheel spin so long at such slow speeds. It's possible that they were using tricks like removing all the seals or something, I couldn't know. I do know that it was very impressive how long that wheel kept spinning. I won't argue with you about the mathmatics and science of it all because you'd win, but from what I've seen it is worth trying FSA's bearings. After all, when it comes to bicycles every bit counts. I also know that when a steel (non ceramic) wheel bearing is in rough shape it is noticable which would mean that bearing quality makes a difference. It seems to that whether or not is is worth the money is a personal/finacial decision, if you can afford it then go for it.
I am not arguing that the FSA bearings aren't amazingly smooth and low-resistance. They may be indeed, I am not an expert in bearing friction or anything like that. All I am saying is, they are pretty much irrelevant!! It is as if you were trying to get better gas mileage from your Hummer, and decided that the way to do it is to replace the seatbelt buckles with a lightweight titanium version

It's all about the law of diminishing returns: if the bearings consume 0.5% of the power you expend riding your bike, then you can reduce the friction by THREE TIMES and still not improve your performance more than 0.37%.

"Every little bit counts" is not very useful advice for almost anyone. If you're a pro tour rider and have basically infinite cash to burn, then sure, go ahead and do these micro-optimizations. But even then (a) you won't actually "feel" a measurable difference in the bearings (and anyone who says they can is suffering from the placebo effect), and (b) it still probably won't make enough difference to help you win.

Consider the cost of these ceramic BBs: $200 for a ceramic bottom bracket. Honestly, how is that a cost-effective upgrade? For $200 you can get a pair of super-high-zoot ultra-light low-rolling-resistance tires, which could increase your efficiency a noticeable amount (say a few %). For $200 you can rebuild your wheels with ultra light aero bladed spokes and aluminum nipples (maybe another couple %). For $200 you can replace every darn little piddly bolt on your bike with titanium and save 100 g or something. For $200 you can get a carbon stem and bars, or a titanium-rail saddle, and save a few grams there too. For $200 you can take a day off work and spend it training and improving your conditioning. There are loads of things that you can do for $200 that might have a slight but significant effect on the weight or aerodynamics of a typical road bike. Getting a ceramic BB seems like the silliest choice of all... it doesn't even LOOK cool

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Old 09-25-06, 08:47 PM   #14
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Drag is certainly a problem, but mechanical losses in top drawer bikes are negligible compared to our old nemesis "THE AIR". If you haven't been optimised in a wind tunnel, all the aero bits you can screw to your bike can be undone by poor rider aerodynamics.

You can save a pile of cash by running DuMonde Tech Liquid Grease in your hubs instead of regular grease. Dura Ace hubs spin for a loooong time with that stuff.

I'd imagine that riding in a gear that cross-chains even a little would cause enough drag to offset the possible gain from high$$ BB bearings...

Remember that the bike industry has to reinvent itself regularly to keep people buying new stuff...
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Old 09-25-06, 08:59 PM   #15
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You can save a pile of cash by running DuMonde Tech Liquid Grease in your hubs instead of regular grease. Dura Ace hubs spin for a loooong time with that stuff.
What makes XYZ brand of high-zoot grease any better than any other?

The only reliable grease advice I've gotten on this forum is that (a) marine wheel bearing grease is good because it's cheap and very waterproof and (b) the research that lawkd shared with everyone on how grease is made and the various applications of it (which basically suggest that plain old marine wheel bearing grease is good stuff ).
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Old 09-25-06, 10:29 PM   #16
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Nah, BikeWise1 is probably right that the liquid grease (probably some kind of oil) will set your wheels up to spin longer than marine grease, because marine grease is much more viscous. He's saying that this is a viable alternative to ceramic bearings. But his main point is that air resistance is much, much bigger than bottom bracket drag, as are lots of other things as well.
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Old 09-25-06, 11:27 PM   #17
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if it is 4% then that is signficant... people lay down a couple grand for zipps to save less than that... that would be 10W at 250W... that's i'd spend a couple hundred bucks for that... i might spend a good chunk of time training to get my FTP up by 10 Watts... but if it is really 0.5 watts then it is not really significant anymore...

anyone know why external BBs would have an order of magnitude greater drag than regular old taper type BBs?
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Old 09-25-06, 11:42 PM   #18
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I think you guys need to realize the 4% was relative to other FSA BBs. Perhaps that was just so they don't get sued for slandering another company's product(s) without any proof but then it was an "independent" study. Either way 4% was meant to be Relative to other FSA BBs. So in other words normal FSA external BBs suck and you need to spend $200 more so they suck less.

OR just avoid anything with bearings from FSA and buy Campy.
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Old 09-26-06, 08:28 AM   #19
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I think you guys need to realize the 4% was relative to other FSA BBs. Perhaps that was just so they don't get sued for slandering another company's product(s) without any proof but then it was an "independent" study. Either way 4% was meant to be Relative to other FSA BBs. So in other words normal FSA external BBs suck and you need to spend $200 more so they suck less.

OR just avoid anything with bearings from FSA and buy Campy.
Well stated. Now if someone "independent" will kindly do tests on ALL the major brands to give us a baseline of the ranges of BB drag at relevant RPM, then we might be able to draw some valid conclusions.

Until such time, IMHO, you are far better off optimising the motor rather than the machine. I'll bet an ill-fitting jersey fluttering in the breeze has more effect at 20 MPH than BB drag...to say nothing of facial hair!

Someday, racers will get plastic surgery to make their faces more aero....maybe delete the nose, and add gill-like slits under the chin!

Have some fun when you ride and don't obsess about your balls. Bearings, that is...
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Old 09-26-06, 09:01 AM   #20
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Quote:
Originally Posted by timcupery
Nah, BikeWise1 is probably right that the liquid grease (probably some kind of oil) will set your wheels up to spin longer than marine grease, because marine grease is much more viscous. He's saying that this is a viable alternative to ceramic bearings. But his main point is that air resistance is much, much bigger than bottom bracket drag, as are lots of other things as well.
Ah yes, you're right! I misinterpreted his post. I agree absolutely, bottom bracket drag is a truly minor consideration
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Old 09-26-06, 10:24 AM   #21
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Originally Posted by moxfyre
I am not arguing that the FSA bearings aren't amazingly smooth and low-resistance. They may be indeed, I am not an expert in bearing friction or anything like that. All I am saying is, they are pretty much irrelevant!! It is as if you were trying to get better gas mileage from your Hummer, and decided that the way to do it is to replace the seatbelt buckles with a lightweight titanium version

It's all about the law of diminishing returns: if the bearings consume 0.5% of the power you expend riding your bike, then you can reduce the friction by THREE TIMES and still not improve your performance more than 0.37%.

"Every little bit counts" is not very useful advice for almost anyone. If you're a pro tour rider and have basically infinite cash to burn, then sure, go ahead and do these micro-optimizations. But even then (a) you won't actually "feel" a measurable difference in the bearings (and anyone who says they can is suffering from the placebo effect), and (b) it still probably won't make enough difference to help you win.

Consider the cost of these ceramic BBs: $200 for a ceramic bottom bracket. Honestly, how is that a cost-effective upgrade? For $200 you can get a pair of super-high-zoot ultra-light low-rolling-resistance tires, which could increase your efficiency a noticeable amount (say a few %). For $200 you can rebuild your wheels with ultra light aero bladed spokes and aluminum nipples (maybe another couple %). For $200 you can replace every darn little piddly bolt on your bike with titanium and save 100 g or something. For $200 you can get a carbon stem and bars, or a titanium-rail saddle, and save a few grams there too. For $200 you can take a day off work and spend it training and improving your conditioning. There are loads of things that you can do for $200 that might have a slight but significant effect on the weight or aerodynamics of a typical road bike. Getting a ceramic BB seems like the silliest choice of all... it doesn't even LOOK cool
You just trying to confuse the issue with the facts

A dura ace b.b. cost around $60. An FSA ceramic b.b. can be found on line for $184. If you are already in the market for a b.b. then this is a $124 upgrade. If the more expensive b.b is more durable then it might be as good of a value in the end. Even if it's not more durable but is a little bit more efficient it would be worth it to some people (usually very rich people). That's for each individual to decide.
No one is debating that wind resistance isn't a larger factor than bearing resistance. The first question is; is the more expensive b.b. better? The second question is; is it worth buying? The problem with all your science is that you forgot to use common sense. If a one bearing is better than another and doesn't cost more in the end, buy the better bearing. Whether or not this applies to the FSA ceramic b.b. I can't say for sure because I haven't tried it but I'd definatley give it a shot before I dismiss it.

Oh yeah.....I think the red annodized b.b. does look cool.
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Old 09-26-06, 11:25 AM   #22
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Oh yeah.....I think the red annodized b.b. does look cool.
Especially the anodizing on the BB shell
Seriously, one thing about external BB's of integrated crank systems is that they're on the outside and can actually serve as bling!

That said, I think the argument made my me and moxfyre is not confusing the issue - it's saying that any gain is so small as to be truly inconsequential.
As to the claims made in the article, it's frankly impossible for a BB change to increase a rider's power output by 4% because BB drag accounts for a very small total of drag on the rider, much less than 4%.
That all said, if the ceramic BB cost the same as the D/A and lasted longer, I'd buy it. I'm not much worried about the friction from the D/A BB.
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Old 09-26-06, 11:36 AM   #23
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Originally Posted by Pete Hamer
You just trying to confuse the issue with the facts
Touché

Quote:
A dura ace b.b. cost around $60. An FSA ceramic b.b. can be found on line for $184. If you are already in the market for a b.b. then this is a $124 upgrade. If the more expensive b.b is more durable then it might be as good of a value in the end. Even if it's not more durable but is a little bit more efficient it would be worth it to some people (usually very rich people). That's for each individual to decide.
No one is debating that wind resistance isn't a larger factor than bearing resistance. The first question is; is the more expensive b.b. better? The second question is; is it worth buying? The problem with all your science is that you forgot to use common sense. If a one bearing is better than another and doesn't cost more in the end, buy the better bearing. Whether or not this applies to the FSA ceramic b.b. I can't say for sure because I haven't tried it but I'd definatley give it a shot before I dismiss it.
Sure, if the FSA BB lasts 3X longer than the DA BB, then maybe it's worth it! But I've seen no evidence of that, not even from FSA, who would surely hype that benefit for all it's worth if they thought it existed. Most sealed bearing BBs are supposed to last ~30,000 miles, not sure how different that is for ext bearing BBs.

The issue I was arguing was only whether the BB could possibly deliver 4% improved OVERALL power efficiency. Summary: IT CAN'T! I agree that there might be other issues that would make one BB better or worse, primarily longevity as you suggest, but have seen no evidence one way or the other on that point.

Quote:
Oh yeah.....I think the red annodized b.b. does look cool.
I think it looks cool too! But how often do you notice a bike's BB. Maybe you occasionally glimpse the left side of it, but not that often. You want flashiness for $200, get a custom pain job
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Old 09-26-06, 12:15 PM   #24
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Originally Posted by timcupery
Especially the anodizing on the BB shell
Seriously, one thing about external BB's of integrated crank systems is that they're on the outside and can actually serve as bling!

That said, I think the argument made my me and moxfyre is not confusing the issue - it's saying that any gain is so small as to be truly inconsequential.
As to the claims made in the article, it's frankly impossible for a BB change to increase a rider's power output by 4% because BB drag accounts for a very small total of drag on the rider, much less than 4%.
That all said, if the ceramic BB cost the same as the D/A and lasted longer, I'd buy it. I'm not much worried about the friction from the D/A BB.
AS far as the FSA claim about 4% increase, I'm not defending that since it does seem high. But if you read there PDF about the "ceramic revolution" on their website you'll see that they are talking about using ceramic bearings in the hubs and b.b. when they make that claim, not just the b.b. (again I'm not defending their claim, just keeping the facts straight)
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Old 09-26-06, 12:23 PM   #25
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Quote:
Originally Posted by moxfyre
Touché


Sure, if the FSA BB lasts 3X longer than the DA BB, then maybe it's worth it! But I've seen no evidence of that, not even from FSA, who would surely hype that benefit for all it's worth if they thought it existed. Most sealed bearing BBs are supposed to last ~30,000 miles, not sure how different that is for ext bearing BBs.

The issue I was arguing was only whether the BB could possibly deliver 4% improved OVERALL power efficiency. Summary: IT CAN'T! I agree that there might be other issues that would make one BB better or worse, primarily longevity as you suggest, but have seen no evidence one way or the other on that point.


I think it looks cool too! But how often do you notice a bike's BB. Maybe you occasionally glimpse the left side of it, but not that often. You want flashiness for $200, get a custom pain job
FSA claims ceramics last 5-10 longer. I can't defend this claim either, but they say it.

"FSA CERAMIC BEARINGS = INCREASED SPEED
Performance Breakthrough - Testing shows speed increases ap-
proaching 4%, i.e., over 1 km a rider can gain 20-40m.
Optimized System - FSA bearings combine ceramic balls with
super low friction seals and special lubricant: an optimized sys-
tem.
Real World Proof - For two seasons, FSA equipped riders have
been winning Olympic medals, World Championships and Grand
Tours with these bearings.
Everyone Benefits - Bearing friction is proportionally more impor-
tant the slower you ride, unlike aerodynamics.
Long Term Investment - Ceramic bearings last 5-10 times longer
than steel bearings.
A Full Range - For 2006, FSA is proud to introduce a full range
of ceramic bearings. You can replace your MegaExo bottom
bracket, your FSA wheel bearings; or the bearings in your
Mavic, Campagnolo, or Speedplay components.
Check our charts for availability."

AS I read the article, http://www.fullspeedahead.com/downlo...InsertBook.pdf ,they are making the 4% claim when using ceramic bearings in the hubs and b.b.

I'm going to try to order some those FSA ceramic bearings today and put it in the boss's bike while he's in Vegas.
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