Weight Weenies

every one try to get the lightest bottom bracket, but im looking for the smoothest one, the one with less drag in bearing.
i heard that durace for example dosent spin alot without chain - ie to much bearing drag.
one has told me that loose bearing bb are the fastest, and some pros still using them (alot in TT) and replace the grease with oil lube as it save energy over long distance.

any comments where can i get loose brearing bb, am i right ?

You should take into consideration the fact that bearing act differently with load than they do without (w/o chain as you mentioned).

Even if the cranks spin "further" without the chain on them, they might be harder to push up an 8-10% hill pushing hundreds of watts through them...

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didnt think about it, thanks.
so the only way is to "lab test" (under real use) the bb to know wich is the fastest.

The FSA mega exo ceramic bb's aren't bad.

2002SaecoReplica wrote:The FSA mega exo ceramic bb's aren't bad.

i was looking at FSA web site and found this:

Tests by the Danish magazine Cykel-Motion (Mar 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%.

Further tests by SKF, and confirmed by the Danish cycle magazine
Cykel Magasinet (Sep 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 0.02W

can't one send his dura ace bb to someone and they put ceramic bearings in it? i thought it is phil wood, but i didn't find it on their homepage.

Hi,
Acros has or is coming with a BB with ceramic bearings for dura ace. I have no further info on this, i read it in cycling+.
J.

simon wrote:can't one send his dura ace bb to someone and they put ceramic bearings in it? i thought it is phil wood, but i didn't find it on their homepage.

Simon, are you thinking of http://www.ceramicspeed.com/ ? They are in Denmark, but I don't think you have to send in the bb, you could just order the bearings and install them yourself (or have the LBS do it for you), this saves you from having to remove the cups from the frame and having to miss the bb for a while.

Edited because I was way too slow.

Boonen seems to know his ways! Good tip!

At Ceramic Speed they are very helpful and they have a ceramic bearing for almost every bicycle part even the wheels in the pulley!

They are helpful guys too! I ride with their BB bearings since 2001 and they still are great no problems at all! But this is not inexpensive stuff! Really high end and those bearings keep going .....

And guys they safe some weight

I do recommend them too!

Simon,

I just had a local shop replace my XTR bearings with Phil Wood bearings using their new tool. I haven't had a chance to ride them yet and they are not ceramic, but if you open the link below you can see the new tool and how to use it. It only took about 5 minutes to have it done.

http://velonews.com/galleries/OBBTOOLINST.pdf

I thought that study quoted on the FSA site was interesting because if you extrapolate from those numbers replacing pedal, BB, hubs and jockey wheels with ceramic bearings could save almost 2.5 watts. (but I still want some!)

2.5W? Wow.. who needs fancy deep section wheels when it costs so much less to just get ceramic bearings instead.

I've tried the FSA ceramics, and wasn't at all impressed. Beyond seals that were tight(which has never bothered me) The bb had
2 bad hitches. Two distinct detents in it. Not nearly as smooth as a campy or Phil wood.

I have to question the FSA study. Although I am not sure, but I suspect that this test was done with ceramic bearings, and then extrapolated to match the FSA bb. I think if this bottom bracket were to be tested, it would not match the numbers that are to be predicted for it.

I am not arguing that significant savings can be made with ceramic bearings, I am a big advocate of using them. I just think that the FSA bearing themselves have some issues. Theres alot that goes into the reduction of resistance because of ceramic bearings, and a big part of that is the tolerances and types of materials used.

So in this case I have to call shananigans.

Nowhere does it say that FSA ceramic bearing were even tested. It says that tests have shown ceramic bearings reduce resistance. I think we all knew this already, As we know that aero rims are more aero than box section. But to say that because a Zipp rim is aero, that someone elses carbon rim is just as aero is wrong.

I don't want to pollute this thread, but I was wondering if there is a company making good ceramic bearings for the record bottom bracket ?

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