crack! sound from left pedal/crank

stabeek

Hi

For the past week, I've been trying to find the cause of a fairly loud crack sound coming from my left pedal (but it could also be the left crank).

It only occurs under stress, so getting off the bike and trying to find it is impossible.

It's also a bit random, it doesn't always occur on the uphills.

It came about rather suddenly, by which I mean, it wasn't a sound that started soft and then became loud gradually.

Initially I didn't bother looking, I guess I thought that some looseness had set in, and I just tightened pedal and then the crank. But there's not much difference. However, the symptom would need to more regular, if it was coming from those.

So I got to thinking that the bearings in the pedal, might, get stuck in a certain position sometimes (this would explain the random nature) and then they go crack. Maybe I should apply some grease.

In any case, I'm writing not for exact solutions, but rather to find out if it's happened to anybody here.

Cheers and thanks for reading.

Brad768

Yeah, I've had the same problem for the past week or two. Not sure if it is actually coming from the pedal or the crank. I would describe it as more of a knocking sound though. It only happens under stress and only on occasion. It's bloody impossible to locate!

Wishbone Ash

Ball bearing becoming loose or unseated?

patrick151

Same issue here. I've had it before and a (over) tightening of my crank arm solved it for a while but it's back. According to the guys in the shop the BB could need a strip so I've booked it in for a look over- I'll report back once I know more

martinbourke11

Same problem here, bike a month old, 1000k done since i got it new, at first i thought it was rear hub issue but cleaned that and still the noise under stress? very hard to figure out where the noise is coming from, narrowed it down to the bottom bracket area. I'm not a small guy so could i be damaging the BB ?? don't like heading into LBS with a vague idea of a problem that usually occurs when out mashing a gear.

colm_gti

Mate of mine is a bike mechanic, told me those hollowtech II BB's are feckers for creaking, even when new. Unless there is lateral play in the cranks you're probably fine.

My bike usually creaks and groans when it wants to be washed :pac:

chester3455

Try taking the bottom bracket out clean it grease it and put it back in tighten it alot.

jinkypolly

chester3455 wrote: »

Try taking the bottom bracket out clean it grease it and put it back in tighten it alot.

This. Same thing happened to me, make sure you give all threads a good clean and greasing.

check_six

My latest 'mystery bottom bracket noise' was fixed by reseating my quick release levers on my wheels and a little grease on my SPD springs.

We need a good name for these mystery tough to trace noises.
Something like 'bobrasqueak' but more elegant.

I bet the Germans have a name for it. Any German speaking bike mechanics out there?

joxerjohn

Could be many things as outlined in previous posts. What type of crank BB are you using ?

I have had this problem with a square taper BB which was clicking under pressure, it turned that a crack on the bearing case of the BB was the culprit. A replacement BB solved the problem.

On another occasion a club mate had the same complaint which I suggested could alos be a cracked BB but turned out to be a damaged pawl in the freehub which eventually failed and had to be replaced.

It is often not easy to locate these noises but these or two posibilities for you to check.

The Big Lebowsky

I was convinced that a persistent clicking sound was eminating from my bottom bracket too, so I duly replaced it....The bike still made the same clicking sound after the B/B was replaced..

I eventually traced the clicking sound to my bikes carbon fiber fork....The fork was a very solid and sweet riding Trek fork with an aluminuim steerer tube...it was never involved in a crash despite being over five years old...

Somtimes these funny noises can be a total pain to diagnose, as they are impossible to replicate with the bike sitting on the workstand.

stabeek

Thanks everybody for the contributions.

check_six wrote: »

We need a good name for these mystery tough to trace noises.

More than a name I'd like to have a good approach or method to "Exact Location Uncertain" problems like this, where you have the "preproblem" of finding the origin. I think Big Lebowsky's experience shows it'd be worthwhile to weigh up the possibilities.

In my case, my strong feeling is, that, after further cycles, the sound is clearly coming from the pedal on the left.

To my discredit, I thought I had hit upon the "great" idea of changing the pedals around, until I realised that their chirality is different, to borrow the biochemical phrase, so I discarded that.

It's possible that the problem could be in my bottom bracket, but the sound is transferring to the pedal and emanating from there. But opening up the BB is a big job for me, and actually I'd rather buy some new pedals before I do that. So that's what I'm going to go out and do now.

stabeek

On my cycle up to the bike shop, the sound became more regular. Especially on certain steep uphills, I could sometimes synchonise into it, and have it repeat.

The upshot was that the pedal started to get really messed up and a wobble settled in, though I was still unsure ... but with new pedals the sound has disappeared, so it was the pedal. A bearing then, most probably ... as Wishbone said.

Many thanks.

OK then.. onto the next problem

strangel00p

Had a similar problem. Really annoying clinking noise coming from the bottom bracket area. Thought the bike was going to fall apart. Eventually put some cheap pedals on and bingo - noise was gone. difficult to isolate noises on a bike

cython

stabeek wrote: »

Thanks everybody for the contributions.


More than a name I'd like to have a good approach or method to "Exact Location Uncertain" problems like this, where you have the "preproblem" of finding the origin. I think Big Lebowsky's experience shows it'd be worthwhile to weigh up the possibilities.

In my case, my strong feeling is, that, after further cycles, the sound is clearly coming from the pedal on the left.

To my discredit, I thought I had hit upon the "great" idea of changing the pedals around, until I realised that their chirality is different, to borrow the biochemical phrase, so I discarded that.

It's possible that the problem could be in my bottom bracket, but the sound is transferring to the pedal and emanating from there. But opening up the BB is a big job for me, and actually I'd rather buy some new pedals before I do that. So that's what I'm going to go out and do now.

While not failsafe, I have something of a system to at least rule out potential culprits that generally works well when the problem lies in a contact point (pedal, crank, saddle, seatpost, etc.), namely to try to isolate each point in turn and see is the problem reproducible. That is to say, try pedalling with only one foot (only really feasible with cleats for full circle), and then the other, then try out of the saddle (rule out saddle/seatpost), followed by trying to either take hands off the bars while cycling, or at least maintain minimal contact with them.

I've suggested this to a few people at various times, and sometimes it has directly found the source, others it has at least narrowed down the search significantly.

Brad768

Will check pedals tomorrow although I don't think it is coming from them. However I also noticed my chain needs replacing.. you never know with these mystery noises! could be anything....

Jocry

I had the same for the past few weeks and couldn't figure out what it was!
Brought it to the lbs today, it all stemmed from the saddle / seat post. Everything tightened and did the 16km commute home this evening, with the hail stones to go with and not a sound out of it!
Might not solve your problem but solved mine from what I can gather!!!