cyclingfrenz1

All

I am getting a progressive worse clunking sound while pedalling - how it appears to be intermittent. Really noticed last night when doing a turbo session. It was definitely worse when there was some tension - high cadence spin it more or less disappeared.

The pedals don't move at all from side to side when I'm off the bike. The sound definitely seems to be coming from the bottom bracket and I think is fairly consistent in terms of where the pedals are through rotation. However I cannot replicate it when I'm off the bike and pedalling with my hands.

Are there any thoughts. I'm quite keen to try and sort myself and upgrade some of my components at the same time.

I am riding a specialised sirrus elite.

Thanks
Cyclingfrenz1

RubberLegs

It does sound like a BB problem. Slip the chain off and see what the crankset sounds like all by itself. It is hard to replicate the torque of a power stroke, but feel for grittiness or catching. It should have smooth, consistent feel all through the rotation.

cny-bikeman

It's a little more difficult to diagnose the problem when we don't have very full info. I'll throw out one educated guess, but if that's not it please provide the info requested below. Your symptoms match what I would expect if the fixed cup on a traditional cup and cone BB is slightly loose. The normal check for play often will not reveal the problem, but higher pedal pressure will cause the cup to shift in the threads. It tends to produce a low-pitched sound or a "clunk" feeling, vs. the click often heard when other BB parts are loose. On rarer occasions the lockring is slightly loose, but people often check that early on.

To check for the problem put your cranks parallel and apply the brakes. Then step on one of the pedals with most of your weight. Rotate the cranks 180 degrees and repeat on the other side. If a cup is loose you will feel the "clunk."

If the above test is negative:

1. What type of BB do you have? Compare yours to the pics below:



Shown above, top-to-bottom: loose-bearing bottom bracket with square taper spindle, square taper cartridge bottom bracket, Shimano Octolink bottom bracket, Truvativ external bottom bracket cups.

2. Did the symptom show up suddenly or increase over time?

3. Did any maintenance or incident happen just prior to the symptom arising?

4. Have you tried anything so far to eliminate it, and have you confirmed it's not the wheel by substituting a different one?

nyrealitydose

Check your crank arm bolts (where the crank arms bolt onto the bottom bracket spindles). I just lost my first ever left-side crank arm. :/

fietsbob

Crank arm loose.. more blind guessing , since it's not in front of me in the shop.

cny-bikeman

No and no again. When diagnosing a problem one needs to go by the symptoms presented rather than jump to a conclusion that may not fit. Slightly loose crank bolts (or pedals, or chainwheel bolt) usually do not clunk - they more likely make a clicking sound. A crank arm that is downright loose is easily felt, will usually evidence itself under relatively low pedal pressure, and will shortly be anything but intermittent. The OP also says there is no play when he tries to move the crank arms back and forth.

I did have some time to look up the specs, and it appears Sirrus Elite always came with a sealed BB unit. The procedure I recommended is the same, though, as the right side of the unit could have slightly backed off. But considering how easy it is to tighten one might just pull off the crank arms and retighten to see if that resolves the problem. While you are at it you can easily assess the condition of the bearings. If there is any rough or uneven feel you can always choose to just replace it.

cyclingfrenz1

Everybody.

Thanks for for your initial thoughts. Will have a look tomorrow and let you know.

Much appreciate ate your views though.

cny-bikeman

You're welcome. One thing I neglected to mention is that generally with cartridge units you can ride them until you either can't stand the noise/play/feel anymore or are concerned about complete failure leaving you stranded (though I've not heard of that happening. Cup/cone BB's are best overhauled regularly so as to keep then in good condition and forestall the need for parts replacement. I really enjoy the older parts, but considering the small practical difference in performance and the ease of installation I would lean toward just putting in a cartridge nowadays to replace a cup and cone - vintage/collectible bikes excepted of course.

cyclingfrenz1

The clunking went away for some time as you can see - and managed to put quite a few miles in. However has now returned worse than ever before! (probably not surprisingly!)

Having tried your stepping on the cranks on either side - I can definitely hear the clunk when putting the pressure on the crank with the brakes on. I'm assuming therefore that it is a loose cup? Does this mean just a tightening is required or to replace the whole bottom bracket?
Thanks

OldsCOOL

Have you ruled out all freehub bearing possibilities? Chains can transmit feel and noise just enough to keep you guessing.

cny-bikeman

Just tightening - crank arms must be removed then tighten first the drive side an then the non-drive side. Both a crank arm extractor and a BB cartridge tool are required. A bike shop or co-op would have both. You can purchase them but especially the BB tool is not something you would need often, especially as BB styles are changing.

lopek77

Everything bellow created similar sounds in the past.

- seat support rails - put some oil where metal goes inside plastic
- bottom bracket - remove, clean very well, grease where needed/required.
- pedals - clean and oil all moving parts
- chain rings - make sure all bolts are tight
- cassette - make sure its not lose

You may also check cables, suspension and any added accessories.
I wasn't happy with the service at my local bike shop, so I started buying all needed tools, watch YouTube videos and now I'm happier with myself than with Specialized certified mechanic lol Its not a rocket science...most of the stuff is extremely easy. All you need is the right tool and common sense.

cny-bikeman

Except that most of your list does not apply to the problem the OP presented. One does not just take a symptom and go down a list of possible causes until the right one is reached. The OP already noted in post #10 above that the test I suggested was positive, indicating that the problem was loose bottom bracket cup(s). "Common sense" is not actually a useful criterion, as it has no clear definition. Rather what is needed is the ability to approach a problem in a methodical and logical manner.

Further the right tool is less important than understanding the goal to be achieved in using the tool. I have field-straightened forks with my bare hands and a straightedge, removed tires with silverware (the handle end of course) used a rock instead of a hammer, a knive edge or point instead of a screwdriver, and straightened wheels temporarily without moving a spoke.

lopek77

"The right tool" may be your bare hands or a rock if it's the only one that can fix the problem lol And that's where common sense and ingenuity comes to play. There is nothing wrong about my previous post. I fixed all the issues myself, and I shared my experience with the rest of what I learned while dealing with similar problem. Don't forget it's a forum and we all want to help.

cny-bikeman

My point is that it's not helpful to give a laundry list of causes unrelated to symptoms or without first narrowing down the possibilities.

I think after 4,000+ posts I kinda knew the point of the forum. I'm all for wanting to help - not the same as being helpful. Saying most of the stuff is extremely easy is not as helpful as explaining how one can make it easier.

lopek77

Your signature says : " There's no such thing as a routine repair.

Don't tell me what "should" be - either it is, it isn't, or do something about it. "
This thread will be read by many, many people in the future. I guarantee you some of them will find it helpful.
I'm not trying to be disrespectful, but number of posts has a lot of to do with... numbers of posts... You may be the smartest guy out there, but this is NOT a proof of it. I'm sure some of them are very good quality - help wise. So...let's stop adding to the number of our posts, the ones that are not helping anyone. PEACE! ;-)

cny-bikeman

My reply merely was a wry response to your implication that I was not aware of the intent of the forum, not to boost myself up. I expect each post to stand on its own merits. My posts above are not a personal criticism, but rather a critique of the "shotgun" method of diagnosis and of the oft repeated claim that bike repair is very easy and only takes common sense. Anyone is welcome to disagree, but it's up to each person to decide what is helpful or not.