BB (?) knocking under stress

yoBob said:

My wife's road bike is making a knocking sound when she stands to climb.
Otherwise, no problems with the drivetrain while pedaling. I thought maybe
the bottom bracket had come loose but I felt no play when yanking on the
cranks laterally.

Does this sound like the BB needs overhaul / lube?

Is there another diagnostic test I can run?

How likely is it that I'm not even looking in the right place? I rode it
today (w/o SPD shoes) so I don't think it's pedal/cleat-related. Could it
be wheel bearing?

I'm probably going to take it in for a needed tune-up but I want to make
sure I ask for everything it needs and spesifically what is causing the
knocking.

Any insight is appreciated.

Check for cracks in the chainstays and dropouts.

My guess is frame flex. I used to get this knocking sound also when out
of the saddle climbing. One day by chance, I decided to adjust my
chainline by moving the Phil Wood BB to the left about 2mm. The next
day when riding out of the saddle climbing no more knocking sound.

yoBob said:

My wife's road bike is making a knocking sound when she stands to climb.
Otherwise, no problems with the drivetrain while pedaling. I thought maybe
the bottom bracket had come loose but I felt no play when yanking on the
cranks laterally.

Does this sound like the BB needs overhaul / lube?

Is there another diagnostic test I can run?

How likely is it that I'm not even looking in the right place? I rode it
today (w/o SPD shoes) so I don't think it's pedal/cleat-related. Could it
be wheel bearing?

I'm probably going to take it in for a needed tune-up but I want to make
sure I ask for everything it needs and spesifically what is causing the
knocking.

Any insight is appreciated.

Try grease it's cheap.
I would start with the pedal threads, if that fixes it go no further.
I grease the crank spindle/crank arm interface, but some seem the think
it is undesirable to do so.
Grease the Bottom bracket threads for sure.

If none of this works check the handlebars and stem.

Marcus

In my experience, you won't feel a loose bottom bracket by yanking on the
cranks laterally, especially one that ticks only under high loads (ie: body
weight!). Well, I can say that for cartridge-style BBs, and assume that this
is what you have.

You've already done 2 diagnostics - removing the shoes and the fact that it
happens when standing - the latter indicates its not likely the seatpost,
which is commonly a problem if it is bone dry in the seat tube (more like a
"tick" not a knock though). It could be the handle bar /stem (but again,
this would be more of a ticking sound), one of the pedals, or loose
chainring bolts. Could be crankarm... Or it could be something stupid, like
a shoe lace against the crank arm, or multitool in the seat bag going from
one side of the bag to the other!

I would say it is in fact the BB. The shop will likely tighten it, clean and
re-grease the threads...wrapping the threads with plumber's tape is
sometimes also done so that there is a compact fit in between the threads .
Around this time of year, with the warmer temperatures is when I find my
bottom bracket cartridge starts to knock. (Aluminum frame with steel
cartridge). Doesn't happen every year, but when it does it always happens to
be spring-time. I suppose the two metals don't expand at the same rate and
after enough warm/hot/cold/cool weather cycles, eventually, I guess, this
cummulative differences in contraction/expansion has the ultimate effect of
throwing off the adjustment, at least enough to make noise. (Anyone more
experienced care to comment on this?)

"yoBob" <[email hidden]> wrote in message
news:OTB%f.12811$WL4.7557@trnddc07...

Quoted message said:

My wife's road bike is making a knocking sound when she stands to climb.
Otherwise, no problems with the drivetrain while pedaling. I thought
maybe the bottom bracket had come loose but I felt no play when yanking on
the cranks laterally.

Does this sound like the BB needs overhaul / lube?

Is there another diagnostic test I can run?

How likely is it that I'm not even looking in the right place? I rode it
today (w/o SPD shoes) so I don't think it's pedal/cleat-related. Could it
be wheel bearing?

I'm probably going to take it in for a needed tune-up but I want to make
sure I ask for everything it needs and spesifically what is causing the
knocking.

Any insight is appreciated.

yoBob said:

My wife's road bike is making a knocking sound when she stands to climb.
Otherwise, no problems with the drivetrain while pedaling. I thought maybe
the bottom bracket had come loose but I felt no play when yanking on the
cranks laterally.

Does this sound like the BB needs overhaul / lube?

Could be...needed remove, clean, lube. May be toasted if it's a cart
bearing one and one of the bearings is history.

Quoted message said:

Is there another diagnostic test I can run?

How likely is it that I'm not even looking in the right place? I rode it
today (w/o SPD shoes) so I don't think it's pedal/cleat-related. Could it
be wheel bearing?

Could be a loose hub bearing as well.

Quoted message said:

I'm probably going to take it in for a needed tune-up but I want to make
sure I ask for everything it needs and spesifically what is causing the
knocking.

Any insight is appreciated.