Tandem Cycling - CDale RT 3000 - pinging noise in bb

Was wondering if any of you have experienced a pinging noise which sounds like it is coming from the captains bottom bracket.

The pinging sound seems to be amplified when the stoker is overpowering my pedal efforts. If I have my wife soft pedal it seems to get quieter or even going away.

I have checked things for tightness/looseness, as well as adjust the timing chain but it again appeared on our last ride.

Any thoughts, comments, experiences?

Thanks in advance :D

Check to see if the bolt(s) that keeps the bb in place is tight.

Was wondering if any of you have experienced a pinging noise

Can you be more specific / descriptive of the 'pinging' noise?

Single creak, popping, grinding, high pitch, low pitch... and does it fall in sync with your pedal strokes and/or during a specific part of the pedal stroke?

Checked the bb bolts, adjusted timing chain and re-tightened bolts. To descibe the sound would be like a mixture of a creak and cable hitting the aluminum frame. It does not seem to synch up with the pedal stroke for timing, but it does become louder when I soft pedal and the stoker provides more power. If we both soft pedal, it seems to go away or is barely audible.

Singles who have been out with us, say it seems to be coming from the captains bb are.

That's just weird... and very hard to diagnose given what you've described thus far.

Hopefully someone with a similar vintage C'dale will come through with something to look for because I'm afraid that at this point all I can offer is the basics starting with the stoker's touch points and some of these won't seem to make sense:

1. If she has a suspension seat post make sure it's not the source by checking for excessive play, any loose fittings, and stiction... which will require her to weight and unweight her saddle while sitting on the bike while you hold it. In fact, if it was me and I had a rigid seatpost in the house that would fit, I'd change out the suspension seat post just to be sure it wasn't the source. Yes, this may be the most unusual suggestion of the lot... but it's a key touch point, Coda's suspension posts aren't the cat's meow, and sound travels in usual ways on a tandem.

2. Check to make sure the chain ring bolts on both timing cranks are tight.

3. Check both front & rear bottom brackets for bearing play by pushing / pulling side-to-side on the opposing pedal-ends of the crankarms.

If it's not something simple like these things I would not recommend tightening anything else at this point; instead, I'd start taking things apart, doing some inspecting, cleaning, and then re-assemble using proper torque specs.

A. Pull both cranks and check the bottom bracket spindles for smooth rotation with your fingers. If a BB feels notchy or is binding it probably needs to be replaced. (requires crank puller)

B. Check and make sure both the fixing cups (right side) and adjusting cups are tight (requires a BB tool)

C. Remove and disassemble the eccentric then clean and apply a light coat of bearing grease to the outer surfaces of the eccentric core and wedge, the wedge bolt threads, and the inside of the frame's eccentric shell before reinstalling the eccentric.

D. Clean the crank / spindle interface and spindle ends and reapply a generous coating of grease to the spindles before reinstalling the cranks and torqing the crank bolts.

Yes, this is pretty much an overhaul of the cross-over portion of the drive train but it's the only way I know to address mystery noises on a tandem that has accumulated a few miles.

Also, check your wheel bearings. Often creaks can telegraph, therefore coming from one area and sounding like they are from another.

I second the motion regarding the sound location. For some reason, tandem noises don't seem to be as easy to pin down as it seems.

Thanks for the replies thus far.

TG, I did test out the stokers suspension post with my rear. I got it to move, but it was quiet. I should probably look to see what model.

I have been thinking about going through the bb's anyway, so I may as well just roll up the sleeve and jump in. It would help me mentally anyway as it was a used bike, just so that I know I went through it before we start going on longer rides. (don't need a mechanical far from home with Wifey...lol)

Prof and jgg3, yes I have been finding out many "new" things as of late... :D But it's all good, if it means my better half will go out with me every week. :)

Thanks again for the replies

We developed a noise during cranking last week with a similar symptom -- it only happened when we were both pedaling hard. Our noise was not a ping, but a click. We had trouble telling where it was coming from -- we both thought it was right below us. Turned out to be that the stoker's eccentric was loose. (We have a Davinci, so there are two eccentrics.) When I pulled mildly hard on the stoker crank (trying to remove it without messing with the crank puller), the eccentric slid out of the BB shell some. I didn't really know much about an eccentric at that point, but I could tell that wasn't right. I ended up removing the whole thing to figure out how I was supposed to tighten it. Pretty cool design. I readjusted the chain tension (and recentered the chainring while I was at it), tightened both eccentrics, and the noise is gone. I'm now thinking I should get a torque wrench, because I could have tightened even further, but I'm afraid of going too far. I can't judge 8-10 Nm by feel.

We are experiencing the same ping noise. What was the fix meant2do?

I once had a similar noise on my Cannondale that sounded absolutely like it was coming from under my feet. It turned out to be the stoker seatpost in need of greasing and tightening. You could probably test this by merely loosening the binder bolt, rotating the seat post a bit, repositioning it and tightening it. Even if it doesn't solve the problem, greasing the seatpost every now and then is a good practice.

It is totally amazing how an aluminum tandem frame can telegraph noise.

Rick