UKH

Proviso - I've minimal bike maintenance skills or tools so will highly likely take my bike to a bike shop to get them to look at it but any thoughts here are appreciated.

So I'm out two nights ago and I start to experience massively loud cracking noises when pedalling (as in people 20ft away can hear me coming). Each rotation sounds as if there's a large rock in my bike and I'm breaking it apart with each pedal stroke. Which is rather alarming but over 100km nothing catastrophic has happened (and I recall it happened once before - around the same time of year, as it starts to get cold and wet - and then went away).

Late night googling gives me lots of solutions for creaking and noises (mostly centred around tightening cranks and greasing or replacing bottom bracket) but little about large cracking noises.

I'll follow the fixes for creaking and see if that helps. But this is far beyond creaking so just wondered if anyone had any similar experiences and would care to share what the root cause was?

Cheers,

Colin

had similar sounds come from my press fit bottom bracket on a carbon frame - not sure what bike you've got but press fit can cause plenty of problems like this. Grease is probably the solution and tightening everything to its proper torque setting too.

Andy, cheers, It's a Bird Zero TR hardtail. Five years old and I'd imagine with a press-fit bottom bracket. I can check. Thanks for your reply.

Cracking as opposed the creaking suggests broken B B bearing to me......

It's your knees!

Any BB movement when you push/pull cranks from the side?

Any relative movement between cranks when you hold one and push/pull the other?

Might be miles off but I had something similar which I thought was coming from a pedal (mostly because it happened almost every time I put downward force on the pedals and turned the crank) but it turned out to be something where the handlebars connect to the frame (sorry, uber technical terms here...).  Mate said it was a bearing that had gone.

It was just hard to actually pinpoint the source of the sound, oddly enough.  It was only when my pal was cycling along side me and I said something like "as you can tell, my pedal is ***ed" and he told me the noise was coming from the handlebars.

It just so happened that me turning the pedals was also putting strain on the handlebars, causing the click....which had led me to believe it was the pedals that were clicking, (and a bit of weird tinnitus that made sourcing the direction of the sound a bit iffy)

Hope I've explained that clearly enough...it's easier in person and with hand gestures.

I'd start by taking the chain off and see if there is any roughness or movement in the cranks. Possibly even take the cranks out and look for the brown staining that is a giveaway for a wrecked BB.

Thought all Bird bikes are alu frames, but could be mis-informed on that.

Road.cc had an article not that long ago about tracing creaks and other noises.

On top of what everyone else has suggested, check the cassette lock ring is not loose. The cassette slamming onto the splines is quite loud.

That'll be your knees. 

Does it stop when you stand up? if it does it could the seat post.

E

I would think your BB falling apart would be the most obvious thing, although when this has happened to me the cranks started wobbling straight away.

Seat posts/clamps can also make quite loud noises but I'd be surprised if that would be as loud as you are describing.

Worth swapping out your skewers to see if it's that.

It’s either hips, knees or ankles. 

Considering how simple a mechanical device a bicycle is, they're a nightmare for working out where a noise comes from.

Hello and thanks everyone for taking the time to input. Much appreciated and I shall investigate each (especially my knees ).

An update is it only stops only when I stop pedalling so that suggests I'd imagine that it's definitely drivetrain or bottom bracket-related. I'll check it out and share what I find.

Thanks, Colin

Particularly so with the echo box of your modern carbon frame.

I had the exact same thing on a new carbon framed road bike.

Replaced BB, sorted.

No really, as when pedalling you are also exerting force elsewhere, such as the handlebars and seat post, unless you are pedalling out of the seat and no hands on the bars either!!

Haven’t ridden in the rain for many years, but in my youth I rode whatever the weather. In those days of the old traditional bottom bracket it was very common to get water inside the bottom bracket. When this happened the most incredible cracking noises would result- I don’t know why. You didn’t need to have a broken ball bearing, something I never saw. The only solution was to dismantle it, dry out the water, replace the old grease and re-assemble. Not sure if this helps when applied to a modern component.

If it is really loud I'd be surprised,  unless you have thighs like tugboats,  if it was the bb. That's normally a creaky sound. Could be the free hub though.

Mine was making a proper crack on each pedal stroke for ages, turned out to be the crank arm.  Eventually it deformed enough to fall off and sort of fixed itself, the ride home was a bit tricky with just one leg mind.

Hi, thanks everyone for their input, including those who replied after my second post above. All much appreciated.

An update is I cleaned the bike tonight (after leaving it manky on Wednesday to jump straight into the shower with waterproofs on) and it became totally obvious what the issue is. Cleaning all the muck out - and being a bit more rough with it -  it appears I've exacerbated some massive play in the pedals (as in, if I grip and shake the left-hand pedal, or push it in the way, the whole chainring and pedal on the other side moves as well). The result being there's now a rather large gap on the none-drive side and I can see a handful of loose bearings inside. I'm therefore assuming it's safe to say that's the root cause and I'll get it looked at and fixed, or replaced.

I'll make my apologies for wasting everyone's time. In my (totally weak) defence, being out on Wednesday in Edinburgh was awful, rain-wise, it was late and I was tired. And there didn't appear any play when I was pedalling, so I was looking for some ideas as to what else it could be. But I should have least gone back out and checked it over in more detail before I posted.

(I have though learnt things from your replies, which is a positive).

So thanks again, Colin

Get your knees checked out first.

I've just seen an article on road.cc reporting on a possible issue with Shimano hollowtech cranks failing:
https://road.cc/content/tech-news/shimano-claims-no-design-problem-hollowte...

worrying- and seems common -ironically it's recently happened to above poster 'felt' (he didn't mention cracking before tho- he maybe here shortly to explain)

youtube.com/watch?v=Rj__lexd_BI&