BB questions

TimeTraveler

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Feb 6, 2012
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#1
As I read FarEast's thread regarding race preparation and chain ring bolts it evoked more thoughts about different drive train components and their influences on cycling performance.​
In particular, the BB. How much impact does the BB have on cycling performance? Is it worth paying for an expensive ceramic BB or going standard?​
What are your thoughts?​
Cheers,​
Kevin​
 

FarEast

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May 25, 2009
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#2
All depends on what type of riding you are doing - Basically even the pro's don't go in for super bling BB's and opt for the top of the range models by thier sponsors - Such as Shimano DuraAce , Campagnolo Super Record or SRAM. I think its only the TT specailists that really go deep in to the rolling resistance created by the BB.

At the end of the day I would suggest the 3 listed depending on your components - most are cheap enough to be replaced every 6 months to keep the super smooth feeling. I did race on ceramic bearings and they were such a PITA to keep clean that I just switched back to DA. I'm currently running Token tiramic bottom bracket due to the BB30 frame and DA 7900 cranks - very happy with them but they also need a good clean once in a while.
 

Yamabushi

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fudoushin.com
#5
I agree with James, go with quality steel bearings. Nowhere on the bike, especially the BB, are there high enough RPMs or high enough temps to warrant the extra cost (and IME reduced durability) of ceramic bearings. Additionally, while under load I highly, highly doubt you could feel any difference whatsoever between quality steel BB or ceramic BB.
 

TimeTraveler

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Feb 6, 2012
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#6
Pete, wouldn’t the benefits of less friction and dag be the same regardless of load? I watched a documentary the other day about replacement of a dilapidated bridge with a prefabricated one built at a separate site, and then moved miles by an amazing modular vehicle to be placed in its permanent location.

After arriving at the location, the bridge was lowered into place with hydraulic jacks that had Teflon coated contact surfaces, with an additional lubricant applied, to enable the construction crew more easily use hand operated hydraulic jacks to perfectly position the bridge within a fraction of an inch on all sides. Here is an image of the bridge on jacks: http://ts4.mm.bing.net/th?id=H.4919692774672399&pid=15.1

If friction, or the lack of, makes a difference with such an extraordinary amount of weight, why would it not make a difference with a BB under load?
 

Yamabushi

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#7
This is a case that when there is no load and you just free spin the crank with ceramic vs. steel bearing the difference appears quite significant. The ceramic BB spins much better. In actual use however, when you actually put the weight of the rider on the BB, the difference becomes negligible. As long as quality steel bearings are used, the difference is imperceptible to the cyclist. Would the difference be measurable? Using sensitive enough equipment, almost certainly yes, but it would be fractions of a percent different, not real world significant. Like in your bridge example, under an extreme load, say the weight of 1000 cyclists the difference may again become significant. That being said, to repeat... in the real world application on the bike under the load of a single cyclist the extremely small performance difference between ceramic and steel, IMHO, doesn't justify the extra cost. I've ridden both and I choose steel.
 
Likes: TOM

FarEast

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#10
Also one more point - it's no good having ceramic bearings in a steel racers - the optimal benifits are ceramic bearings with ceramic racers also you need to be running the bearings "DRY" or with paraffin which is basically what the Pro Tour Mechs do. As you can see this is a HUGE PITA!

the only place I would drop that amount of cash on bearings is in my race wheels - no other place on the bike requires them.
 

TimeTraveler

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#11
This is a case that when there is no load and you just free spin the crank with ceramic vs. steel bearing the difference appears quite significant. The ceramic BB spins much better. In actual use however, when you actually put the weight of the rider on the BB, the difference becomes negligible. As long as quality steel bearings are used, the difference is imperceptible to the cyclist. Would the difference be measurable? Using sensitive enough equipment, almost certainly yes, but it would be fractions of a percent different, not real world significant. Like in your bridge example, under an extreme load, say the weight of 1000 cyclists the difference may again become significant. That being said, to repeat... in the real world application on the bike under the load of a single cyclist the extremely small performance difference between ceramic and steel, IMHO, doesn't justify the extra cost. I've ridden both and I choose steel.
Pete, thanks for the detailed explanation. Sounds logical to me.

Also one more point - it's no good having ceramic bearings in a steel racers - the optimal benifits are ceramic bearings with ceramic racers also you need to be running the bearings "DRY" or with paraffin which is basically what the Pro Tour Mechs do. As you can see this is a HUGE PITA!

the only place I would drop that amount of cash on bearings is in my race wheels - no other place on the bike requires them.
Fareast, thanks for the information.

Ceramic is sicker though.
Owen, I am with you on this one, but considering the points that Pete and FarEast have presented I must select logic over cool.:cool:
 

GSAstuto

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Oct 11, 2009
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www.roadfixie.com
#12
I'll chime in a bit. The common bearings are ball / race construction. Ceramic balls are harder than steel. Same with the races, but ceramic races deform more than steel. Friction is increased when then ball encounters deformities or a constricted path. Ceramic balls on steel races with actually smooth the surface over time. Steel balls on steel surfaces will cause the bearing to become worse, actually, as the race will develop a wavy surface. Ceramic requires little if any auxiliary lubricant , so high speed friction is dramatically reduced. For low speed operation, some lubrication is required to reduce the static loading. So, what's best on a bike?

99.999% of the situations a common, high ABEC steel bearing with low tension seal will perform as good as the equivalent ceramic.

.0001% of the times, the ceramic will make a discernible difference. Mainly as the bearing ages, or if there is a significant environmental issue.

To get the best static and dynamic resistance from a ceramic , you should run them nearly dry and without edge seals. Obviously this will require very frequent maintenance. So exactly as FE points out , you'd get a super slight decrease in friction, but you'll spend a lot more time on cleaning.

My personal favorite is using ceramic coated ball with steel race In a standard edge seal package. The harder balls will actually grind up muck a little better and over time do not cause the race to become wavy. Otherwise, I will stick solidly to a precision steel bearing like NTN, EZO, TPI, Enduro or SKF. All common bike bearings are a standard dimension, so, the only difference is slight changes in the seal configuration and lubrication packed. For severe environment , the I'd Ed stainless bearings, like Phil Wood.

You want the smoothest BB then focus should be more on the chainset axle configuration and BB housing. As any distortion there will cause way more friction than a commonly supplied bearing. That notwithstanding, the the best BB configuration would be using double row, reduced ball count bearings. But only Gokiso makes them as far as I know, and they are basically unobtainium except for a few pro riders. (Yet). Besides that, I'd run the makers BB without any reservations whatsoever. I use. DuraAce BB w/crank and never touch it. On CX, a GXP crank Ina BB30 and its never been touched in more tha. 3 seasons. (Loaned to PDX team)
 
Aug 27, 2012
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London, UK
www.macrophotofly.com
#14
IMO the grease inside the bearing and rubber seal probably cause more resistance than the difference in (two quality) bearing materials in a BB. I was seriously disappointed when I fitted a new BB to my bike and found it was like treacle at first. Obviously loosens up once you get a couple of hundred k's on it.
 

TimeTraveler

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#15
I was seriously disappointed when I fitted a new BB to my bike and found it was like treacle at first. Obviously loosens up once you get a couple of hundred k's on it.
macrophotofly, sorry to hear about the disappointment with the new BB. I know what a let down it can be to have high expectations for a new part that just does not perform the way you"d like. This forum has definitely helped me to avoid making disappointing parts and components choices. BTW, what is the BB brand.;)
 

GSAstuto

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Oct 11, 2009
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www.roadfixie.com
#16
You can easily check your bearing for the type of seal,it has:

ZZ - No edge contact. Open metal shield.
LLB - Rubber version of ZZ. Slightly more protection, but very little drag.
LLU - Double lip drag seal. Good environment protection , but increase in drag. (I typically use these in freebody end brg)
LLC - High contact. Great environment protection. High drag. Actually a good bearing for mucky conditions and touring / CX wheels.

Almost always I will use LLB spec bearing for performance road bike. And even remove the inner seal completly. Ceramic ball BB bearing with LLU seal is very good. I use a German / Taiwan brand called YUNIPER. Made by TPI. If you don't touch them , they last a long time, well, I have actually yet to wear one out, so not sure how long! Shimano DA bearings are similar , they use a coated ball in micro polished race. Campy uses ceramic coated balls in nitrided race made by FAG (German) IMO, the DA, CULT (Campy) and YUNIPER are simply the best available anywhere in terms of friction, environment and durability. Now, when I can get a Gokiso.......hmmm