BB30 - best alternative/replacement BB standard?

[drossall]

My son has a Boardman CX Team. Overall it's quite a nice bike, but the bottom bracket has consistently been utter rubbish. He had it back to Halfords for creaking when he first had the bike. A while ago, the left crank fell off on a ride. We got some parts and some Loctite 641, and did a strip and refit a few weeks ago. It's just fallen off again. The bike's way out of guarantee, obviously.

Personally, I've never really progressed beyond square taper, which I have on all my bikes. Newer standards have passed me by a bit. I've seen the remarks about BB30 around the Web and, if anything, I get the impression that the Boardman/FSA combination is about as bad as it gets. It's a Gossamer chainset. Could even be a PF30 - there are plastic sleeves in the BB - but I'm still figuring out the difference.

So it's time for a new crankset, which I think may also mean an adaptor, in order to get to a standard that actually works as well as square taper? What does the panel recommend, more in terms of alternative standards than of models, though any comments welcome?

[giropaul]

Best as in best at any cost, or best reasonable?

Best would be C-Bear or custom made Hambini.

Best without breaking the bank is probably Wheels Manufacturing or Praxis Works

I can’t see any reason to change the crank set entirely.

Even with a conversion, it’s still a press fit at the end of the day.

[citoyen]

I can’t see any reason to change the crank set entirely.

I dunno. If the left crank keeps falling off, does that maybe suggest either the spindle and/or the left crank is damaged? So a replacement is probably required.

Even with a conversion, it’s still a press fit at the end of the day.

Good point. If the BB shell is less than perfectly formed, an adaptor won't fit any more perfectly than a new BB30, and will probably still creak.

[FifeingEejit]

Since square taper BBs are usually sealed cartridges which means decent ingress protection, you're not going to get anything like that from an outboard bearing system.

I've got an FSA gossamer on a Cannondale Synapse and BB30a BB; it only really creaks when the bearings are shot.
If the cranks are falling off, it's more likely someone's put them on wrong first time round.
There's a load of weird shit going on with the FSA system including a wonky washer and a nut inside a nut IIRC, if you dont' have the outer nut tight then the inner one isn't going to hold for long... or was the nut inside a nut the SRAM system... erm I should probably go and double check that.

Your best bet is probably a BB30 to HollowtechII adapter.
Pretension, pinch bolts and a retaining clip are reasonably fool proof...

But it's still pressfit, and you've still got potential tolerance allowances between the width of the shells and the width of the adapters, and the cost of an adapter is a lot more than the cost of a bearing and crank.

[citoyen]

I'm still figuring out the difference.

Bikeradar did a decent summary guide to all the different standards a while ago - looks like they're keeping it up to date as well:
https://www.bikeradar.com/advice/buyers-guides/the-complete-guide-to-bottom-bracket-standards/

[drossall]

Thanks all. There are possibly a few things here that are assumed, but I don't in fact know.

In particular, FifeingEejit's "...it's still press-fit..." suggests that I could actually put the same cranks back into a BB from a different standard, provided that it fits the shell of course. I come from a world where a different BB type means new cranks. I'd just taken that for granted.

Given that, we don't necessarily need a new crankset. I'd agree, though, with citoyen's assessment that the left crank is probably for the scrap heap. We could keep the right and change BBs, it seems, although I hadn't realised that - but FifeingEejit's comments imply that another brand of crank might be more reliable. Nonetheless, the core issue is a crank that comes off, and I'd simply associated that, perhaps wrongly, with BB problems. Certainly, the first time, half the BB came out as well - but that could have been effect and not cause. And there's the creaking, but some articles suggest that all press-fit types can do that.

Giropaul asks a sensible question about budget, the answer being that this is a decent bike but over five years old, so we're up for a new crankset and BB (if needed) as normal maintenance/wear and tear, but not to getting into territory where a new bike would be more sensible. You'd hope that £100 would cover it (with Dad providing free labour, obviously).

So, in summary, I think we need a new left crank at minimum. I share with at least one of you doubts about whether it's a good idea just to replace that, and thus stick to a weird system. So that's a new crankset (I'll hope to swap the rings, if I can get something of the correct BCD). But, if we're doing that, and there are doubts about the BB30 system, do we go the whole hog with some kind of adaptor and a different system?

I did look through one or two guides before posting. I'll read the Bikeradar one again. I realise from those that not all BB standards take the same axle size/length, but none of them said explicitly that you can swap standards for the same crankset, even sometimes.

[Somnolent]

Chances are it's not the BB itself, but lousy tolerances on the BB shell of the frame (or piss poor alignment of the holes left and right)
If you can stand the sweariness, it might be worth you having a look at Hambini's youtube channel.  He goes into this problem in some detail on a number of manufacturer's frames.  He "roasted" Boardman in a video a while back, but that was taken down after a piece of quite gratuitous offensiveness on another topic.  His own solution to this is rather expensive (and very nearly always out of stock) event if technically superior.  There are plenty of other converters though. I think I'd be inclined to convert to a Shimano 24mm axle.  That said if the shell in the frame is really wonky, even with a converter you may find you get quite poor bearing life.

 

[Torslanda]

BB30 is a wonderful solution to a problem that no one had until Cannondale invented it. The bearings are tiny and, often, pressing them out of the shell makes the shell go oversize. Hence the BB creaks, the shop installs new bearings and 6 weeks later you're back to square one.

I would advocate a change to a threaded BB. Initially this looks expensive and/or tricky to do because it rquires a converter, chainset and new bottom bracket. In the long run - especially if you ride in all weathers - things tend to even out.

For your Boardman I would suggest and FSA or similar BB30 conversion sleeve with any compact Shimano chainset - R560/Tiagra/105 etc. - and its attendant BSA thread BB. But there's nothing to stop you fitting Stronglight, FSA or anything else you fancy.

The converter comes with full instructions and cab be fitted with a headset press or a vice* or a sash/G-clamp and hardwood blocks

*The vice would have to be a bloody big one thobut...

[drossall]

Thank you. I have a Park headset press

Does the fact that the Boardman has the plastic sleeves that I mentioned around the BB30 make any difference? They won't mean that the shell is slightly larger or anything? Though I can measure it tomorrow of course - bit dark in the shed now

[Torslanda]

Think that's PF30, different bore size. Principle is the same though.

They're really, really shit...

[TimC]

I have a CX Team as my general do-anything winter cum pottering bike. I quite like it - I've even done a few 100km Audaxes on it. It's a bit later than yours - mine has a Sram Apex 1x drivetrain, but the BB is the same. I've not had any trouble with mine, but I have two other carbon Boardmans that I've converted to Shimano threaded outboard bearings using a one-piece insert. I can't remember the name, but I'll have a look in the morning. With a press, it's an easy conversion. The CX Team, being an alloy frame, has a BB shell made from a piece of tube. That doesn't mean it won't be out of round - welding heat could well have distorted it - but at least it should be concentric across the BB, which is one of the things Hambini has found to be an issue with quite a few carbon frames.

[drossall]

Well it's a slightly odd set-up. Definitely PF30 sized, but see the shoulder inside the shell, which reduces it probably to BB30 size in the middle:


The original BB is an assembly like this, with a central sleeve that is presumably to prevent water ingress. So some of those convertors aren't going to fit past the shoulder, I think?


Not much point in ordering something and having to send it back. Pity, as the Praxis ones looked quite good. I'm sure the FSA one won't fit.

[TimC]

I've used both of theses solutions, and they've both worked perfectly (in carbon frames).

Hope PF46 Convertor

FSA BB30 convertor sleeve

The Hope one should fit your frame, I would have thought - might be worth talking to them.

Edit: Boardman did produce versions of this bike with Shimano chainsets. It might be worth finding out how they did that - it may be that they used a particular conversion device.

[FifeingEejit]

Thanks all. There are possibly a few things here that are assumed, but I don't in fact know.

In particular, FifeingEejit's "...it's still press-fit..." suggests that I could actually put the same cranks back into a BB from a different standard, provided that it fits the shell of course. I come from a world where a different BB type means new cranks. I'd just taken that for granted.

No, pressfit is how the thing fits into the frame (as in rather than threaded)
So if you put a hollowtech2 adapter into a BB30 shell, the adapter is pressfit into the frame so is still going to suffer from the issues of pressfit which is manufacturing tolerances.
the only way you'll get round that is by having a threaded shell bonded into the frame. (which isn't far off what that sleeve thing is although it's still pressed in not loaded up with an IFT of araldite)

Soemthing else to be aware of is that Cannondale in all their wisdom decided that they needed to tweak BB30 and made the incompatible but still 30mm axle BB30a.


In all outboard bearing BB systems the left crank is attached to the axle by some arbitary method made up by the manufacturer.
Shimano's is simplest as you're simply clamping the crank onto the axel with the assistance of splines that means you can't get it wrong or find it slipping. (Basically like an aheadset clamp but with splines)
FSAs is a complex of 2 boltsm one that threads into the thread in the middle of the axle (like the preload headset cap) but with a second bolt that stops the first bolt from coming loose, if the second bolt is loose the first one can also come loose and the bolt falls out and the crank falls off... or is that SRAM, or both or gah why so bloody complicated!

Look at the instructions on this for a power meter crank for the FSA left crank fitting:
https://www.power2max.com/wp-content/uploads/2018/05/FSA_BB30_Road_Installation.pdf

Part 8 is the critical bit, if the retaining nut is loose the bolt can come out, if the main bolt is loose, it can come out, if the wavy washer is no longer wavy the whole lot has play and the bolt can end up coming out.  Cock up refitting the cranks and the whole lot is in danger of coming out...
Spin the main bolt back on to hold the crank and check the retaining outer, IIRC it needs some stupid tool to tighten,

HollowTech2 is relatively simple and almost foolproof... unless the fool forgets to tighten up the clamp bolts after the preload. 

If the cranks are definitley faulty rather than just pernickety I'd ditch them in favour of a BB30(a) to 24mm HollowtechII (24mm) adapter and a set of shimano cranks.

You also get natty reducers from FSA that allow 24mm axle systems to work with 30mm BBs

https://www.chainreactioncycles.com/fsa-pf30-24-reducer-road-ee085-/rp-prod129801?gs=1&sku=sku465538&istCompanyId=8d42cf00-fc35-44ce-8770-97ae3ffd4c16&istFeedId=c759ee22-6d7f-4501-bd00-f1af47c60490&istItemId=iwxtwalrp&istBid=t&pgrid=60711843258&ptaid=pla-425335075819&utm_source=google&utm_term=&utm_campaign=PLA%2BAll%2BProducts&utm_medium=base&utm_content=mkwid%7CsVU3Yggn6_dc%7Cpcrid%7C309840119912%7Cpkw%7C%7Cpmt%7C%7Cprd%7C465538UK&gclid=CjwKCAjw7-P1BRA2EiwAXoPWA8Ah73Dhnze1sSbULYufuo4UwEiOiCf7enBd_c4xdFTrbq6fRNufQBoC9ZMQAvD_BwE

[TimC]

Yes, I should perhaps have added that my motivation for changing the BB mounting method from BB30 (or PF30) to Shimano outboard bearings was to be able to use Shimano chainsets, which aren't available in any other format (unlike SRAM, for instance). The conversion doesn't obviate the problems endemic in the press-fit system, though both the solutions I've used do at least alleviate the bearing problems caused by non-concentric and ovalised bearing housings by moving them to a machined shell. That doesn't mean they won't creak - though I've been lucky and mine don't!

[drossall]

Yes, but my point was that the FSA PF30 adaptor, for example, is never going to clear that shoulder inside the BB shell, so I won't be able to fit it. The Hope one is a candidate, but expensive (especially in the right length and with a tool to fit it). FifeingEejit's FSA reducers look like an interesting possibility.

The FSA crank we have just takes a single bolt. But as it's not holding well, trying Hollowtech with those reducers might be sensible. It's quite an investment though to find out!

Yes, I understand what press fit means. It's just that there seem to be several different ways for cranks to be assembled, all of which fit several different outer diameters and other types of BB. Whereas with square taper, it's one design of each, even if you mix and match manufacturers.

[TimC]

The reducers solution does work - they're fitted as standard on one of my bikes, and I even have a spare set somewhere. And that's almost certainly the cheapest option. But if creaking is a feature of your son's bike's BB, you're obviously not going to cure that this way. Refitting the existing BB with some kind of threadlock compound may alleviate the creaking for a while. As you say, it doesn't look like the FSA sleeve will work in that shell, but the Hope one may do - for £55-ish, plus the cost of a new chainset of course, but a new chainset seems to be on the cards whatever happens. It's a shame that the FSA shell won't work, as I believe that would have accommodated a traditional square-taper BB if that was the way you wanted to go.

[drossall]

Unfortunately Loctite 641 didn't work last time. But good advice all round. Yes, shame about the FSA shell.

[drossall]

How exactly do the FSA reducers work? It looks as though they sit in the existing BB and use its bearings? Am I missing something?

[TimC]

How exactly do the FSA reducers work? It looks as though they sit in the existing BB and use its bearings? Am I missing something?

Exactly that.

[drossall]

I've found this, which is more affordable than the Hope but better than adaptors, so I think we'll go for it. Should just about fit past the shoulder. I hope!

Thanks for the help in thinking it through.

[TimC]

Maybe I've misunderstood where you are and the associated postal costs, but $70 is pretty much the same as the £62.99 the Hope PF46 BB costs at Chain Reaction.

Edit: for some reason, the first time I clicked on it it came up at $70.25! The second time, I got the UK price of £56.58. Very strange!

[drossall]

Sorry, I never bothered to point it out, but CRC prices vary by BB width. They also only have one or two, rarer, sizes in stock. If they had 68mm, which they don't, it would be £105, which is hard to justify. A few places that do have stock are slightly cheaper, but not much.

I'm in the UK, and the price I'm seeing for the Wheels one, on the link I gave, is £56.69 from a UK supplier, where we can also buy the chainset and hence keep any shipping costs down. I haven't checked them, but the shop uses use Royal Mail, so they shouldn't be excessive.

The site is probably trying to auto-detect whether you are a UK or overseas customer, and showing pricing accordingly. Although there's no sign of a widget to set your country. Might even be a feature in their shop software that they don't normally use, feeling ignored and getting its oar in anyway. The fact that you and I saw slightly different prices suggests that they might actually be pricing in a currency other than Sterling - which might make sense if they are buying Wheels stock in dollars.

[TimC]

Yes, £105 is a bit pricey! As I recall, I paid nearer £55 when I bought one, but that’s a couple of years ago now.

[FifeingEejit]

The FSA crank we have just takes a single bolt. But as it's not holding well, trying Hollowtech with those reducers might be sensible. It's quite an investment though to find out!

Definitely a gossamer? Or did I make that up?
I can get a picture of mine later if I can be arsed going out to the garage.
It looks like a single bolt but isn't, the bike shop I got the bike from warned me about it at the time.