comradehoser

I just had a brand new shimano hollowtech compact crank and BB put on my bike after some bad experiences with a truvativ elita one-piece crankset, namely: non-drive side side crank arm falling off and then eventually some super-loud BB ticking.

I was pleased as punch with the compact crank, it made the bike feel like new--lots of power, stiff, easy rotation, no noise, flawless shifting--until my last ride and this morning. sure enough, non-drive side crank arm under load is generating some little trt-t-t-t-t like noises, on the down and upstroke. No noise when pedaling easy.

The noise itself doesn't bother me so much, it's what it might say about the BB. Am I wrecking the BB threads or shell? Should I stop using it immediately? I'm pretty sure the shell has never been faced--could this be a source of the problem?

I'm somewhat unfamiliar with the hollowtech one-piece system. With square taper BB ticking I just reef on the BB to make sure it's snug in the shell and then reef on the crank bolts to make sure they're well on. Hollowtech seems like that might be a bad idea/overkill, as it seems to work more like a threadless headset.

Any suggestions, or is this a case of advanced diagnosis and treatment?

TO11MTM

This is indeed more like a threadless headset. The cranks need to have the preload cap loaded to a specific tension. Check your service manual if not sure... it's a suprisingly low amount of force... but it has to be close to the right amount. Too little or too much and you'll experience problems.

Anyone on the forum who knows me will tell you I'm the first to vote for facing BB threads on an external bearing setup.

comradehoser

thanks meing.

bike shop dude told me that facing BBs wasn't as much of an issue with newer components, but was absolutely critical with cup and cone BBs. I buy the latter part of that, but I agree with you that cartridge bearings also need to be in good alignment with each other. How much of that alignment is imparted by the spindle, I don't know.

Even though I'm a DIY guy, I think given the history of problems I've had with this, I may seek professional help.

TO11MTM

Facing BBs is something that I reccomend you do get help with on the first go...

A: The tools are expensive
B: If you do it wrong you can make repairs a lot more expensive.

It was more important with Cup and Cone BBs because of the way that Cup cand cone BBs functioned. It was less important with cartridge BBs because the cup primarily juts held the cartridges in place.

On an external bearing setup, if the sides of the BB shell are not flat enough the bearings will not be parallell.

Come to think of it, I forgot to mention the first ting to try and check:
Caliper 4 points of the BB shell from end to end in an X formation. If more than one is off from the other, I would immediately face the BB.

comradehoser

that's a very good suggestion.

why didn't I think of that?

I guess that's why I come here--to milk the wisdom.

I've decided to bite the bullet and take it into the shop tomorrow and ask the head mech dude to first tighten everything to spec, and if there's still noise, to inspect the threads and chase & face if need be. I'll suggest your procedure, too.

and it definitely is the BB making the noise. just swapped out the wheels and pedals--still the same ticking coming from the BB area.

comradehoser

just got back from the shop.

so, I explained the problem, and they diagnosed it thusly: took chain off and spun the cranks, no binding/tight spots = acceptable facing/bearing alignment.

Took off the BB, regreased the shell threads, reinstalled bb, tightened to spec. Done.

No more ticking! And I'm buying myself a hollowtech BB tool!

(we'll see how long this lasts)

Cadfael

Not sure how much this will help.

But I have found whenever I have had occasion to remove my cranks, that after a few miles they will begin to 'click'... I will tightnen them again, and after few more miles they will again begin to click. Eventually the problem goes awy... until the next time I remove my cranks.

The solution was actually in a thread regarding greasing quick release skewers, and involved a misconception I had been following. That of greasing bolt threads. When fitting the cranks I would ensure no grease was on the crank axel, nor on the cranks, I would also make sure the bolt was grease free...

I can just see those in the know shaking their heads in pity.

.. because I realised from that thread I needed grease on the crank axel, and on the bolt threads... I needed the crank to really travel up the axel as far as it would go the first time... and no move again! I could really crank up the torc with less fear of shearing the crank bolt...

The lesson was learned.

But before that... the tell tale sign was the clickety click noise, I thought it was the BB, or the pedals.. it was actually loose cranks.

dirtbag214

all new bikes should be preped.....taped, faced, honed and checked for frame alignment.it's a one shot deal, so go for!......but only a pro shop will have the tools.

DMF 

ANOTHER six month old thread!