Yet another clicking noise

[martint235]

So Lelly has developed a very pronounced revolutionary click. It's almost certainly coming from the drive train (riders alongside me have also thought this) but I'm not going to rule out another source just yet. First job is to rule out the drive train though so I'm going to:

• Remove left crank arm and grease the bolts holding it on. Should I also grease the spindle that slides in (it's a Hollowtech II BB) or is that just asking for trouble?
• Remove the BB shells and grease the threads and the threads in the frame. I can't see any way to get grease into the shells of the BB, they appear to be sealed units.
• Grease the spindle where is slides through the BB shells
• Remove each cranks bolt on the drive side and grease the threads and the bit that rubs against the hole in the crank.

Is there anything else I've forgotten? It's worth mentioning that the click is like a power meter, louder the more power I'm putting out.

 

[busman]

I have a similar problem. I only get the click when asserting power through the pedals. If I'm free wheeling or pedaling with no real pressure on the pedals the clicking dissappears

 

[martint235]

My initial thoughts were crank bolts so I tightened them up to no avail. I'm now just going to throw grease at everything that can be greased.

 

[potsy]

Seat post?

Can you replicate the sound whilst it's up on a stand or is it just when it's under load?

 

[martint235]

Seat post?

Can you replicate the sound whilst it's up on a stand or is it just when it's under load?

Fairly sure it's not the seat post as occurs out of the saddle too.

I couldn't replicate on the stand last time I tried but on the last outing it was much worse so maybe when it's on the stand later I will be able to hear it.

 

[Hacienda71]

My clicks have sometimes been from the pedals, so I would look at those if what you are doing is unsuccesfull.

 

[martint235]

My clicks have sometimes been from the pedals, so I would look at those if what you are doing is unsuccesfull.

My pedals are XT SPDs which I think are sealed units so not a lot I can do with those other than replace them. I will add taking them off and greasing the threads to my list though

 

[Racing roadkill]

Look at the wave washer on the drive side of the crank, or it could be the circlip in the BB, or the pedal axels need nipping up. Whenever I've had the rhythmic click issue recently, it's been one of these buggers causing it.

 

[roadrash]

seeing as it also happens when out of the saddle, i know this may sound silly but check your stem bolts too,

for clicks creaks and noises.........http://www.jimlangley.net/wrench/keepitquiet.html

 

[potsy]

And your cleats..

Not looked closely at my XT pedals but if they are anything like other Shimano spd's then you can definitely service them.

 

[Yellow Saddle]

Hollowtech BBs are notorious for clicks due to a design issue. The bearings are outboard of the BB shell and when you are pedaling the leverage causes movement inside the BB shell on the threads. The two cups, when viewed from behind or the front, thus alternate with up/down movements. Compare this to a traditional BB with internal bearings. Here the entire shell moves up and down by flexing at the seat tube at about the area where the FD is clamped.
This movement in Hollowtech BBs causes a fretting motion between the cup's threads and the frame's threads that causes the noises. It is exacerbated by the fact that there is aluminium in there. Aluminium is noisy when fretting because the microscopic particles which are removed by the fretting oxidises rapidly into aluminium oxide, an abrasive material. Combined with silica brought into the threads with the water that gets in there, this is a noisy affair.

There is no cure, only maintenance. Regularly remove the BB and clean the threads on the frame and cups. Then apply copper compound and refit.

Do not think that grease will seal the interface. It doesn't. In fact, it helps water get in there by way of emulsifying the water and then keeping it where it can do damage. The water reaches the BB not via the threads, but via the seatpost. It is important to have drain hole in the bottom of your BB. If there isn't one or it is blocked with a guide screw, drill one. It is a worthwhile upgrade.

The latest press-fit BBs don't solve the problem either. They are a solution to the problem of not being able to thread carbon but they are especially creaky. In this case the silica that gets in there sticks to the softer plastic cups - embed if you like - and rubs away at the carbon. Carbon structures amplify noise and a little fret becomes a huge creak.

External bearings are a necessity because of legacy BB shell sizes. To fit a large hollow crank spindle and bearings inside the old small BBs is impossible and the bearings had to be moved outboard. Unfortunately solutions such as BB30 where cartridge bearings are slip-fitted inside a big shell, produced problems of its own.

So far the most mechanically perfect BB is the square tape BB with cartridge bearings such as Shimano UN 54. Progress is not always better.

 

[ianrauk]

Martin, when you take out the BB cups, clean the threads and reinstall using ptfe tape instead of grease.

 

[martint235]

Martin, when you take out the BB cups, clean the threads and reinstall using ptfe tape instead of grease.

For reasons that don't need to be gone into, I actually do have some of that stuff!

I won't quote all of YS's post but thanks for that, it does explain at lot.

 

[Yellow Saddle]

Martin, when you take out the BB cups, clean the threads and reinstall using ptfe tape instead of grease.

PTFE tape is indeed a better option than grease but not as good as copper compound. The latter prevents galvanic corrosion, aids removal and resists emulsification.

 

[ianrauk]

For reasons that don't need to be gone into, I actually do have some of that stuff!

I won't quote all of YS's post but thanks for that, it does explain at lot.

It's what my VN came with, so when I changed the BB to the new one I just did the same thing and not had any probs since I changed it over 2 years ago.