clicking bottom bracket

[Danneaux]

Andrew,

I've mentioned this on the Forum before, but it might prove helpful once again...

Have you tried a mechanic's stethoscope? The two I have were some of my most useful tools when I did auto repair. Each consists of a steel shaft that goes into a plastic bulb (Sound chamber) and then rubber hoses attach to two junctions in that, leading to earpieces. Works a treat for finding things like bad water pumps without need for disassembly; same for alternator bearings. One of these stethoscopes located the creak in my Brooks saddle almost immediately -- the nosepiece was creaking on the forward loop of the saddle frame. A strategically placed drop of oil rendered it silent.

You can make your own version using a screwdriver (really! I'm not winding you up). Place the tip on the part you're checking and then press the handle end hard against your head, just ahead of or behind your ear. You'll hear all sorts of creaks and clicks via bone conduction. Just move the tip 'round till you locate the source of the noise. Mind you watch your nose and ear, as they can get a bit close to moving parts. For this reason, a long-shafted screwdriver works best of you don't have the official version of the mechanic's stethoscope.

Quickly taken photos below for your viewing enjoyment. 

Best of luck,

Dan.

[ají]

thanks Dan! so I could do this whilst a friend pedalled on a trainer?

[Danneaux]

...so I could do this whilst a friend pedalled on a trainer?

Yes, sure -- so long as you are careful to not get yourself wound up in the machinery. It can happen. I once saw a guy lose part of his finger while using his other hand to pedal a fixed-gear bike in the repair stand. He reached down to flick a bit of dust off the chainstay and forgot that with no chain tensioner, the drivetrain can be pretty unforgiving. Same for a Rohloff, so be careful.

Also, if your friend is pedaling, watch out for his feet. They describe a much larger circle than the cranks/pedals. I got popped in the nose once trying something similar.

All the best,

Dan.

[ají]

will do, this sounds like a great way to diagnose, well worth it.

[David Simpson]

I like that idea, Dan. I have heard of a mechanic's stethoscope, but I've never heard of that trick with the screwdriver. Great idea.

I had a picture in my mind of Andrew riding his bike with one end of a screwdriver pressed against his skull and the other end on his bottom bracket, listening for any unusual sounds.

- DaveS

[ají]

I had a picture in my mind of Andrew riding his bike with one end of a screwdriver pressed against his skull and the other end on his bottom bracket, listening for any unusual sounds.

- DaveS

yep, that's what i originally thought too, and i was going to mention it, but luckily thought better of it!

[ají]

i also thought maybe get a friend to run alongside me with a screwdriver to their head as a I rode , and they would also be touching diverse areas of the bike while keeping pace.

[John Saxby]

Anyone care to write the Pythonesque script for the youTube vid that will go viral?

[David Simpson]

Anyone care to write the Pythonesque script for the youTube vid that will go viral?

Ironically, the Monty Python gang already did a sketch called "Bicycle Repairman".
https://www.youtube.com/watch?v=U01xasUtlvw

Best line (delivered by John Cleese): "See how he uses a spanner to tighten that nut!"

No screwdriver-to-the-skull though.

- DaveS

[macspud]

Thanks aji

These shots any good?

Is your eccentric centred in the bottom bracket shell (left to right)? your photos seem to be showing that the eccentic is off centre towards the left side? that could mean that the grub screws are getting a poor grip of the eccentric. You could check the dents that the grub screws have made, see if the dents are off towards the edge of the meaty part off the eccentric or are running centrally.

[jags]

this system is  all a load of hassle (i was going to say something else  but Dan would only delete it ) ,obviously you need this stupid BB for the even  more stupid rohloff hub .give me a break worst system ever made.

[High Moors Drifter]

You can make your own version using a screwdriver (really! I'm not winding you up). Place the tip on the part you're checking and then press the handle end hard against your head, just ahead of or behind your ear. You'll hear all sorts of creaks and clicks via bone conduction. Just move the tip 'round till you locate the source of the noise. Mind you watch your nose and ear, as they can get a bit close to moving parts. For this reason, a long-shafted screwdriver works best of you don't have the official version of the mechanic's stethoscope.

It wasn't that long ago when it was quite usual to see water board engineers checking stopcocks in the road for mains leaks using a steel rod with a wooden ear piece which was pressed against the head. As a result I also have used the screwdriver with wood handle to check for leaks in pipes etc.

Id.

[Matt2matt2002]

Thanks aji

These shots any good?

Is your eccentric centred in the bottom bracket shell (left to right)? your photos seem to be showing that the eccentic is off centre towards the left side? that could mean that the grub screws are getting a poor grip of the eccentric. You could check the dents that the grub screws have made, see if the dents are off towards the edge of the meaty part off the eccentric or are running centrally.

Yes, I had wondered about that.
I lined up the chain running from the top of the chain ring to the rear cog by eye..
Is there any other way of doing that? I can appreciate that if the chain doesn't run ' true' then there will be excessive wear.
I agree. The EBB does ' protrude rather more than I recall before I started my exploration for the click noise.
Comments very welcome.
Matt

[Danneaux]

Matt,

I align my eccentric so it is placed evenly between the edges of the BB shell. At that point, my chainline aligns as it is supposed to.

To align the eccentric evenly, I usually use my fingers as a guide, checking with a thumbnail to make sure it is even side to side.

Best,

Dan.

[Matt2matt2002]

Thanks Dan.
I'll give that method a go.
I think that was how it was set before I brought on the click issue.


Would a laser pen be of any use aligning up the chain with front and back ring/ cog?