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PostPosted: Fri Nov 09, 2012 4:52 am 
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Looks like we need a sister site...frictionweenies anyone?

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Posted: Fri Nov 09, 2012 4:52 am 


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PostPosted: Fri Nov 09, 2012 5:06 am 
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PostPosted: Fri Nov 09, 2012 5:56 am 
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If anything, this is an interesting study. I won't say if it's relevant to real-world systems, but cool nonetheless. I might buy it just because.

Hint Hint: I bet the dura ace chain ranks as the one with the least friction!


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PostPosted: Fri Nov 09, 2012 4:31 pm 
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It's definitely not real world and will be misleading in some cases. It is a start however.

I wonder how receptive they might be to additional input on their data acquisition architecture? Real knowledge of bearings would be a plus as well.

Fixtures lacking the appropriate range of load vectors ain't going to cut it. It wouldn't hurt to add the element of time in their plots as well. Something on the order of the average life of a bearing in this application.


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PostPosted: Fri Nov 09, 2012 4:55 pm 
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I would lean towards ignoring bearing life though.

When you're talking about performance at the friction level, like in Formula 1 racing, durability is not near the top end of the priority list though.


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PostPosted: Fri Nov 09, 2012 9:32 pm 
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Bridgeman wrote:
I wonder how receptive they might be to additional input on their data acquisition architecture?


Email him and ask. But if you are proposing a much fancier system, I doubt that is going to happen... at least not anytime soon.

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PostPosted: Fri Nov 09, 2012 11:46 pm 
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Hi,

maxxevv wrote:
I would lean towards ignoring bearing life though.

When you're talking about performance at the friction level, like in Formula 1 racing, durability is not near the top end of the priority list though.


+1.

Besides, within say 5 years we'll likely have zero friction, infinite life bearings anyhow. The tech is there so it's just a matter of time.

Ciao, ;)

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PostPosted: Mon Nov 12, 2012 1:17 pm 
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Here's a dutch look into ceramic bearings: http://www.bikeboosting.nl/index.php?lgi
Google translate: http://translate.google.com/translate?s ... .php%3Flgi

On the left you find a menu, you click there to read the other pages.


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PostPosted: Mon Nov 12, 2012 7:42 pm 
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Thanks... that's a great article. Ceramic bearings provide essentially no benefit by themselves, but the aggressiveness of the seals and the type and fill of grease in a bearing can make a big difference.

One objection though. The grease and seals take awhile to "break-in". If they tested right after packing the bearings, then their measurements will be inappropriately high.

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PostPosted: Mon Nov 12, 2012 9:13 pm 
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This forum is usually anti-ceramic-bearings. Now a story like this comes along and people become all in favor of it.

I can't personally vouch for power savings gained from friction alone. But I wouldn't dismiss any potential gains out of hand either. My only concern regarding the relatively substantial power savings has to do with the actual testing of it. Bearings and chains feel alot smoother far before that level of power loss can be discerned by the human rider. A clean and fluidic drivetrain motivates the rider to push harder (well at the best of times anyway.) A clean drivetrain really only lasts a few kms once stepped out on the course.

A highly viscous lubricant was used in the chain and then coated the chain with a wax.


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PostPosted: Mon Nov 12, 2012 11:34 pm 
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Hi,

Quote:
Ceramic bearings provide essentially no benefit by themselves, but the aggressiveness of the seals and the type and fill of grease in a bearing can make a big difference.


That is exactly what I've always said on this forum: don't go for ceramic hybrids just to gain some Watts. The ones you can buy are more often than not just standard industrial bearings and those (together with regularr steel ones as well anyhow) are really not designed for our puprpose, i.e. low speed, low rev.

There are however other advantages to ceramic bearings which do allow them to be used with far less viscous lubrification and non-contacting seals.
For that to be possible and last for at least as long as a typical steel bearing you'll need to find the right lubricant (oil or grease) and, more importantly, a well made ceramic hybrid bearing.
They are out there and no, they do not have to cost an arm and a leg to be of fine quality either.

Only then there will be a small wattage saving but more importantly (to me at least) they will run more consistently throughout their useful life provided they're being serviced accordingly. (see the appropriate Bell curves)
Seals can be broken in prior to mounting them in a bike which is what's been done by several Pro team mechanics whenever deemed beneficial.
Grease is run in as it is pushed aside which is one reason to use bearings with only a say 60% percent pack rate (unless there is no seal at one end of it). As Frieke says, smaller balls cut through it more easily as well.
Last but not least, go for bearing with phenolic retainers or better. Steel retainers in ceramic bearings are out.

Oh, and if you must use ceramics with contacting seals then you'd better use grease as well. If not the seals will run dry which will increase friction dramatically.

Ciao, ;)

P.S. Current Campa CULT bearings are essentially grooved ball bearings with adjustable preload, not true cup and cone bearings. Seals can be set up so they're non-contacting (only for the more patient among us) or, if you're willing to maintain the bearings regularly, you can run them "al fresco" which is very straightforward without the seals present.
I've done some checking for wear on the Cronitect treated cones and have found none whatsoever even after 30.000km on just a few drops of Triflow.

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PostPosted: Fri Nov 23, 2012 2:49 am 
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Hi,

Digging this up again as I thought you guys might be interesting in this one:

https://www.bike-components.de/products/language/en/info/p31966_X10-SL-DLC-Limitierte-Auflage-10-fach-Kette-Modell-2012-.html
It's a DLC (DiamondLikeCarbon) treated 10S chain from KMC.

DLC coatings are particularly interesting as treatment as components treated with it can be run without any additional lubricant as it is so hard that it is virtually frictionless.
No more lubes, no more seals etc.... :D

Sorry if it has been discussed here already but it's actually the first real world bike product I come acrross using this high-tech.

Ciao, ;)

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Last edited by fdegrove on Fri Nov 23, 2012 11:57 am, edited 1 time in total.

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PostPosted: Fri Nov 23, 2012 3:54 am 
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The KMC chain has been out for a while. No 11speed version, though. And like their ti nitride chain, the coating is applied after assembly, which is unfortunate, as much of the wearing internals don't benefit. I asked them about why this was. Apparently, pre-assembly, the parts are in big containers and get shaken to have pieces fall through slots in the right orientation. If they were already coated, some would scratch off from contact. Too bad.
Kcnc makes cables with a dlc-like coating, available at Fairwheelbikes.
Rockshox has their downhill Boxxer fork with a Blackbox dlc coating on the upper tubes.


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PostPosted: Fri Nov 23, 2012 10:15 am 
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Yes DLC is very hard, but won't running a very hard chain (DLC) against a softer, untreated (non-DLC) cassette and chainring surface just lead to excessive wear to these unprotected surfaces?

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Posted: Fri Nov 23, 2012 10:15 am 


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PostPosted: Fri Nov 23, 2012 11:15 am 
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DLC is very hard and very, very smooth, so it will slide without abrading.


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