Tell me about ceramic BB bearings please!

[Globalti]

Got a Specialized Roubaix with FSA BB, which has outboard ceramic bearings. Now after 1000 miles these are beginning to develop some slack, there's about 1-2mm of play at the crank ends. They have BC1.37"x24T written on them as well as Mega-Exo.

Questions:

How long are they likely to last now?

How do I work out what replacements I need to buy?

My neighbour has the tools including the small torque wrench and I'm confident I can do the job, it's just that this is the first time with these new-fangled bearings.

 

[GilesM]

Some of the outboard BB bearings don't last very long, Race Face seem to be very bad, not sure about the FSA ones, I would fit a Hope BB, they seem to last much longer, I've had a steel bearing one in my full suss for around 18 months now, the Race Face one lasted about 3 months. I am sure that the Hope will fit the Specialized frame, however if send Hope a wee e-mail they will definately confirm this.

When I remove or fit the external BB I prefer to use this tool as it locates all around the cup and is less likely to damage the alloy cup.

http://www.chainreactioncycles.com/Models.aspx?ModelID=20236

 

[accountantpete]

Ceramic bearings are supposed to be harder wearing than steel - but it's like everything else in that there are cheaply produced ceramics and more expensive ones.

I have looked at various works as regards the efficiency and the most favourable supported only a 5% increase in efficiency over steel - if you could believe the study.

You can get grade 10 (the best) steel bearings a lot cheaper - if they are sealed bearings you need the external diameter,internal diameter and the width.Check eBay as you find industrial bearings are the same size but a lot cheaper.

 

[Landslide]

Ceramic bearings have a couple of advantages - lighter weight (for a given size) which can be desirable, and better performance at high temperatures which is largely irrelevant for cycling purposes.

As accountantpete says, you're better off spending the money on a better grade of bearing.

 

[Globalti]

Ah, okay - so does this mean I can just go to my local bearing stockist and buy the equivalent steel bearings and fit them inside those alloy cups?

 

[02GF74]

look at www.simpolybearings.co.uk ... or similar webist.

and if the race is the same for ceramic and steel, then the ball bearigns should be interchangeable.

oh, does not something need adjusting, kinda weird that the ceramic ball bearings are foobarred since they are meant to be more durable.

 

[RecordAceFromNew]

kinda weird that the ceramic ball bearings are foobarred since they are meant to be more durable.

As accountant pete said, I also looked for and found little evidence showing the practical advantage of ceramic ball bearings. In fact what convinced me it is a marketing gimmick for our application, is that if the bearing race is still made of metal, then being less hard it will remain the weakest link for wear. On the other hand, ceramic is more brittle, and may not survive impact loading once flaws have developed on the bearing races so well.

 

[accountantpete]

I don't know the model you have but CRC has replacement steel bearings for £10 or Ceramics for £140 - I know which I'd go for!

http://www.chainreactioncycles.com/Models.aspx?PartnerID=79&ModelID=40215

Besides if you just oil the bearings you will get better performance than the ceramics in all probability - albeit with a shorter lifespan

 

[Globalti]

Verrrrry useful, many thanks!

 

[redjedi]

I recently replaced the bearing on my Campag external BB. I had the choice of £15 steel or £65 ceramic.
As above, I was told that ceramic would last longer but more brittle to impact. Since my bike is in daily use I went for the safe option of steel (I've been known to have to odd accident )

As for weight saving, is there anyone in the world who could really tell the difference between ceramic and steel bearing once fitted to a bike? What is the saving 1g?

 

[Globalti]

When I get the steel bearings I will weigh them both to 100th of a gm and let you know!

I also have (probably unfounded) concerns about the ceramic bearings being brittle, I look forward to taking them apart and examining them. Maybe I'll whack them with a hammer too.

 

[02GF74]

Maybe I'll whack them with a hammer too.

be sure to be wearing safety specs, just in case