Ceramic BB

Discuss light weight issues concerning road bikes & parts.
GothicCastle
Posts: 110
Joined: Mon Jul 04, 2016 1:52 am

by GothicCastle

MomentumR5 wrote:We all know that we lose watts through the drivetrain and wind resistance.


How many watts do you lose through the bottom bracket?

morganb
Posts: 517
Joined: Wed Mar 15, 2017 5:30 pm

by morganb

My experience with Ceramicspeed has also been bad. My Crux frame came with them and they were spinning poorly and making noise after a few hundred miles. I still haven't ridden it in the mud or even wet so its not from bad conditions either. I'd consider running a C-Bear though, not for the ceramic but because their adapter solutions seem the best for Rotor cranks on non BBRight bikes.

Delorre
Posts: 913
Joined: Sat May 24, 2014 12:09 pm

by Delorre

The Ceramic Speed bearings in my Rovals are not that brilliant either. They don't spin freely (but I had the same with other DT240 based hubs), but already a little rough after only 4000 miles of use. Regreased them, but not any better. I'm looking to replace them with regular SKF or similar good quality steel bearings.

morganb
Posts: 517
Joined: Wed Mar 15, 2017 5:30 pm

by morganb

Delorre wrote:The Ceramic Speed bearings in my Rovals are not that brilliant either. They don't spin freely (but I had the same with other DT240 based hubs), but already a little rough after only 4000 miles of use. Regreased them, but not any better. I'm looking to replace them with regular SKF or similar good quality steel bearings.

My teammate's CLX50s needed the bearings replaced in the rear hub after 3 or 4 months of race only use. They ended up replacing them under warranty.

MomentumR5
Posts: 71
Joined: Fri Aug 25, 2017 3:47 am

by MomentumR5

GothicCastle wrote:
MomentumR5 wrote:We all know that we lose watts through the drivetrain and wind resistance.


How many watts do you lose through the bottom bracket?


C’mon man. You know I can’t compute that. Sure, Ceramic makes sense in high RPM applications like motor sports and so does the lubricant. Reduced friction means you go faster, period. And that’s what these ceramic companies are claiming. Not longevity.

Just like any product that we buy. We go off of the manufacture’s claim and our own experience with that product. My VCRC BB has been on my R5 since 2012. I have never serviced it once. I’ve ridden through all conditions. Would it be better if I did service it? Sure, but it’s not needed. My BB spins freely as t ever did and my legs feel faster with them.

I also had Enduro and Ceramic Speed. Both were more than VCRC and didn’t last as long. Maybe their lubricant or bearing quality isn’t as good. Things are not designed to last forever.

Here at Weight Weenie, we can be extremist when it comes to bike building. $60 for advantage or precieved advanatge isn’t going to break the bank.

AJS914
Posts: 1957
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

It's one thing to prefer a bottom bracket solution but don't fool yourself that the ceramic bearings themselves are doing much for you. The only possible wattage gain is going to come from the friction of the seal that may be missing from the ceramic bearing. How much is that? 1/3 of a watt? It's certainly not 3 watts. It's not worth an extra $100.

hambini
Posts: 128
Joined: Tue Nov 15, 2016 8:13 am

by hambini

The difference between 2x ceramic bearings and 2x fully sealed steel bearings is about 0.25W

The difference between 2x ceramic bearings and 2x steel bearings with non contact seals is about 0.02W

The ceramic argument is based on a spin test that really looks great on youtube. In loaded scenarios, it's no where near as good as that.

Additionally, the bit that the ceramic purveyors don't tell you is often their bearings come with a C3 clearance and their friction after only a few 100km will exceed that of a steel bearing.

GothicCastle
Posts: 110
Joined: Mon Jul 04, 2016 1:52 am

by GothicCastle

MomentumR5 wrote:C’mon man. You know I can’t compute that.


Hence my statement. If some magic ceramic bottom bracket existed that saved 25 watts, we’d all know about it. But it doesn’t. You just “believe” there is some advantage. I think that my bike is faster after I clean it, but intellectually I know it absolutely is not. And I certainly wouldn’t spend money on a magic bike soap that claimed to make me faster.

It is very odd that on a site dedicated to something quantifiable (bike weight), these unquantifiable “advantages” keep coming up.

People want to believe that ceramic bearings give them an edge because spending a few dollars is easier than training harder.

So back to the original question, no, not worth it.

Butcher
Shop Owner
Posts: 837
Joined: Sun Jan 03, 2010 4:58 am

by Butcher

My only experience is with the Campagnolo bearings on my SR crankset. I have never had to change them [new in 2011]. That alone is worth the money.

No one has mentioned that the ceramic balls are lighter than steel. What has happened to Weightweenies?

AJS914
Posts: 1957
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

I never had a Chorus bearing go bad either.

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Calnago
Posts: 5788
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

Hmmm, I’m with @Butcher on the longevity of Campy Cult bearings. Unlike most “ceramic” bearings which are a hybrid of ceramic balls and steel races, Campy’s CULT bearings have specially treated races as well. I’ve yet to have to replace a set. Chorus bearings on the other hand, will often need replacing after a wet winter season.
Last edited by Calnago on Tue Nov 07, 2017 4:40 pm, edited 1 time in total.
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Rexenes
Posts: 4
Joined: Tue Oct 10, 2017 10:07 am

by Rexenes

I see that vcrc-bb can be provided with a "cyclocross-sealing" for additional $20.. any thoughts around that? Worth it for my race-bike? Never use it in rain if its not a race.

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DMF
Posts: 1062
Joined: Sat Dec 06, 2008 10:14 am
Location: Sweden

by DMF

Let's just for the sake of argument take a purely scientific approach here, just for a minute...

Let's assume that it is pretty much physically impossible to produce a steel ball that is absolutely perfectly round, because we know this to be true. And let's also take into consideration that steel balls are at a microscopic level anything but smooth, the surface on ball bearings is under microscope pretty rough, and add to this that steel balls are pretty soft and subject to deformation under use in a bottom bracket.

Now, let's consider making a ceramic ball, first of all it is quite possible to get it pretty much perfectly round, measurably rounder than any steel ball. This is a fact, I'm not making that up. Then let's assume that it won't deform under pressure of, let's say, your legs pushing down on it...

Now, let's say the ceramic balls are perfectly round and the steel balls are not, then there is no point in measuring the microscopic differences between individual steel balls as these measures will vary depending on which side of the same ball you measure. Not perfectly round, remember?

You are able, technically speaking, to make a ceramic ball just about perfectly round, but the fact of the matter is that it is seriously difficult (impossible) to make several balls the EXACT same size, they will come out of polishing in slightly different sizes...

Here's the trick though, without naming the big ceramic brand who actually does this, it's quite possible to sort all the inconsistencies in size by their inconsistency and there by achieving pretty much perfect tolerances thru having all the same undersized balls in one bearing and all the same oversized or otherwise inconsistent balls in another bearing, making every individual bearing "perfect".

Now take a scientific approach here, could there not be a difference, albeit a small one, to this level of possible perfection?

Also, power meters don't lie and NO ONE, has EVER, gotten anything but a measurable drop in watts with upgrading every bearing on the bike to high quality ceramics. But just swapping the BB and nothing else? That's more about a buttery feel in the pedal stroke. Just like you won't drop 1kg with a change to carbon handlebars, but carbon everything will.

I will say though, that as friction in bottom brackets go, the quality of the frame dictates a lot, and I've seen a lot of really horrible tolerances from both open moulds to really high end brands.

MomentumR5
Posts: 71
Joined: Fri Aug 25, 2017 3:47 am

by MomentumR5

Rexenes wrote:I see that vcrc-bb can be provided with a "cyclocross-sealing" for additional $20.. any thoughts around that? Worth it for my race-bike? Never use it in rain if its not a race.


I get the cross seals. A good thing to have.

MyM3Coupe
Posts: 132
Joined: Thu Nov 24, 2016 10:32 pm

by MyM3Coupe

Look at Hawk Racing for excellent bearings and BBs. My BB30 bearings in my Time have been maintenance free and spinning beautifully for over 15,000 miles.

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