[MT63]

I’ve had my pinnacle dolomite almost exactly a year now and it looks like the FSA bottom bracket is starting to go again. This will be the second time I have replaced it. I reckon I average about 90 miles per week. I rode my old Trek hybrid for about a year and a half covering the same route and didn’t have any issues. Is this normal wear for this type of bottom bracket or is there a better lasting one I could install?

Topic

[ian t]

Is this FSA BB the one with

Is this FSA BB the one with the internal sleeve ? Will the ultegra BB replace this ? 

[Leeroy_Silk]

Giles P, your Grandad sounds
Giles P, your Grandad sounds awesome!

[mike the bike]

Although my heart belongs to
Although my heart belongs to Campag’ and I know nothing of failure rates, hardness rating or cantilever forces, I am quite sure that the best, reasonably priced BBs I have used in over fifty years of cycling have all been Shimano. And that includes their Hollowtech II, which have never given me a second’s trouble. Were I planning a round-the-world trip I would specify Shimano without hesitation.
Whilst I would admit that others, by the likes of Hope and Chris King, are quite superb, they invariably cost much, much more.

[allanj]

Interesting- I’ve just had to
Interesting- I’ve just had to replace my FSA BB rather early and was annoyed with myself for allowing water in. Maybe it’s not all my fault!

[Chuck]

Slight thread hijack: Anyone
Slight thread hijack: Anyone know if Pinnacle MTBs also ship with FSA BBs?
I’ve got one and was a bit surprised to discover after a few wet rides that the BB gets seriously gummed up, to the point that when I get it out again there’s noticeable resistance turning the cranks. It’s my first MTB with an external BB, so I assumed that’s just what you get, what with all the extra crap thrown at it when riding off road- I’ve never noticed anything similar with my Shimano BB-equipped road bikes.
Now I’m wondering if it might have a particularly naff BB in there.

[Giles Pargiter]

As far a I can remember
As far a I can remember ceramic ball bearings have a slightly higher friction coefficient and have a significantly lower rockwell hardness rating, than even case hardened steel bearings. So you can expect them to wear faster. I think I’am right to say that they are primarily designed for high temperature situations. They may be fractionally lighter ie. literally one or two grams, but basically are inappropriate on a bicycle.
As for twisting the spindle – you would have a job to do that on a mild steel one never mind carbon steel and you would’nt lose the energy anyway because it will be returned when you relieve the pressure. I know my grandfather way back in the fifties, used to delight in amusing himself by making BB’s with aluminium bearing shells, with polished full hardened steel races. He made the spindles from Duralumin and made them hollow, with, again full hardened steel polished races fitted. He used them with full hardened ball bearings manufactured as accurately as possible at the time (this all happened in the late fifties- early sixties). Then he fitted them to a tandem (as well as solos). He had first calculated the stresses involved. This bore out in practice, they used to last years and years and he and my grandmother went all over the UK and many parts of Europe so equipped. The cranks were of course fastened with cotterpins then.
You used to be able to purchase square drive BB’s so made although without a hollow spindle, which takes a lot more “trickery” to manufacture due to needing solid ends.

Be interesting to see what the engineers on here say; but ball bearings have the lowest friction of all contact bearings and if the radii of the races is properly calculated, even the miniscule torsional twist that occurs should be accomodated by them?

Conclusion being that modern parts manufacturers are selling us inappropriate “tat” at stupendous mark ups, that have no advantage to us as cyclists at all. If judiciously chosen a cheap (ten quid or so with spindle) square taper BB will out last all the ones mentioned so far – except the campag square taper.

[DaveE128]

In my opinion (as a design
In my opinion (as a design engineer), the external bottom bracket design is not a particularly good design. Bearing alignment is highly dependent on the shell being perfectly faced and the screw threads being straight, undamaged and clean. Having the bearings effectively cantilevered out from the frame on a screw thread is a bit odd when they deal with the kind of forces they experience under sprinting.

I think that low cadence is far more likely to accelerate bearing wear than high cadence – for the same power output the forces are higher for low cadence, as I expect that twisting loading on the bearings caused by flexing of the whole system (crank shaft, BB bearing holders, shell flex) will have a much more significant effect on wear than the number of cycles from a higher cadence when there is less flex due to lower forces.

[wycombewheeler]

I remember having a bad
I remember having a bad experience with square taper, where the square was rounded off and an otherwise sound sealed bottom bracket needed replacing, but what was wrong with splined sealed bottom brackets? Easy to install, last for ages.

I fail to be convinced by the argument that I need a larger crankshaft diameter, it certainly doesn’t add to longevity, having had to replace BB30 within a year of buying the bike. I don’t think I produce so much torque that twisting of the shaft under load is costing me significant power loss.

At least the original external bottom brackets were use serviceable, simple screw in threads, unlike press fit.

[PhilJC]

Totally agree with Giles.
Totally agree with Giles. Square taper campag veloce bb in my training bike has been going for 9 years, including all year round commuting (mudguards help), and it’s still really smooth (“buttery smooth” in magazine speak!).

[Jack Osbourne snr]

dazwan wrote:Jack Osbourne

dazwan wrote:

Jack Osbourne snr wrote:

You are right in that they are more expensive though.

I’m serious when asking this, would you consider a ceramic worth the extra outlay? basically, if it costs 3 times the price, is it expected to last at least 3 times longer? I would consider ceramic if thats the answer to MY woes.

No, I wouldn’t consider them worth the extra. What I would do is look for a better enclosure for them in order to minimise the ingress of water and road slurry (which will shaft ceramic bearings).

ie. I’d look for a bottom bracket that was designed for use outside of the Atacama desert.

What is also worth doing is looking for premium steel bearings with better seals than the cheap shit FSA seem to specify. They’ll almost aways need packing with grease though.

[gmac101]

I have been to at least one
I have been to at least one lecture on reliability engineering and there were several graphs of showing time to failure – most complex items have what they call an “infant mortality” curve with most failures early in life and they then settle down to a lower level of failure. If I remember correctly bearings had a constant level of failure, i.e. the % risk of failure did not rise or fall with age. The lecturer said that the reason for this was not clear but he felt (this was in a marine engineering context ) was due to variability in the fit and installation of bearings. It surprised me that such a basic engineering component wasn’t better understood. Any way Timkins who make a significant amount of the worlds bearings produce a brochure of “pretty” pictures of failure – see if you can spot yours

http://www.timken.co.uk/EN-US/products/maintdiag/Documents/5892-Timken-Bearing-Damage-Analysis-with-Lubrication-Reference-Guide.pdf

[Rupert]

Had an FSA bottom bracket
Had an FSA bottom bracket with ceramic bearings and bought it thinking that it would last much longer than a bottom bracket with normal bearings. #o How wrong I was.

:S So I bought a new one thinking that maybe I fitted it wrong or something. Nope, new one lasted about 5 months before it started to creak and grindand changed it for a different make (rotor) that has been working for about 2 years now without any problems.

It might be that I was just unlucky and my legs are so powerful that the FSA bottom bracket couldn’t cope on the other hand it might be the design of the BB and other people have been having the same problem with the FSA bottom brackets.

Then again maybe they have redesigned, after all my issues with them are now 4 years old, and I have moved on to bottom brackets I can trust.

[PonteD]

Jack Osbourne snr wrote:You

Jack Osbourne snr wrote:

You are right in that they are more expensive though.

I’m serious when asking this, would you consider a ceramic worth the extra outlay? basically, if it costs 3 times the price, is it expected to last at least 3 times longer? I would consider ceramic if thats the answer to MY woes.

[Jack Osbourne snr]

Judge dreadful wrote: I think

Judge dreadful wrote:

I think a lot of people buy a (relatively) inexpensive bike, then try to ‘smash out’ a cadence of ( let’s say for arguments sake) 90. Then they wonder why the BB fails so early. In short, if you want to ride like a serious rider, you’re going to need serious kit. Eventually my steel PF30 did fail, I replaced it with a ceramic FSA PF30, and I’ve been able to ‘smash out’ a cadence of 90, and not had the same worry about the durability. I’ve not had any problems with the Italian BB in my other bike thus far, which kind of adds weight to the argument, that you get what you pay for. A couple of people I ride with went down the route of adapting a steel PF30 to HollowtechII, then changing chainsets / cranks. It didn’t help them much.

What utter tosh. Who told you that cadence would have an effect on bottom bracket longevity?

If anything, a lower cadence would have a detrimental effect… Albeit highly unlikely.

Poor seals and a lack of grease are the downfall of almost every steel bearing pf30 bottom bracket. Ceramic bearings don’t corrode with the presence of water hence they work better in pf30 setups.

You are right in that they are more expensive though.

[Judge dreadful]

A lot of people I ride with,
A lot of people I ride with, have had the metal FSA press fit BB’s fail on them. I had to point out, that I feel that the use of such a BB (in particular the metal PF30), is more about keeping the cost of the bike down, than any blarney about having more flexibility in frame manufacture, if we have a frame built with a press fit friendly set up. One of my road bikes has a fairly low grade, metal FSA PF30 BB. I managed to keep it alive for a couple of years, doing up to 12000Km’s a year, by keeping my cadence down, and making sure I kept it clean, and lubed properly. I think a lot of people buy a (relatively) inexpensive bike, then try to ‘smash out’ a cadence of ( let’s say for arguments sake) 90. Then they wonder why the BB fails so early. In short, if you want to ride like a serious rider, you’re going to need serious kit. Eventually my steel PF30 did fail, I replaced it with a ceramic FSA PF30, and I’ve been able to ‘smash out’ a cadence of 90, and not had the same worry about the durability. I’ve not had any problems with the Italian BB in my other bike thus far, which kind of adds weight to the argument, that you get what you pay for. A couple of people I ride with went down the route of adapting a steel PF30 to HollowtechII, then changing chainsets / cranks. It didn’t help them much.

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