redryder

We have a 2004 Cannondale Road Tandem (with approx 1,000 miles). When we ride over 25 miles the front bottom bracket starts to make noise. It starts off with random noise and then increases with every rotation. Bike went to local LBS last week and they looked at it and stated a screw was loose in the bottom bracket (they tightened). Went for a 40 mile ride on Saturday and at the 25 mile mark it started up again. By the time we ended our ride, at 40 miles, the noise increased to where it sounded like someone was sawing a log. Should the bottom bracket be replaced? Is this a common problem with aluminum bikes? Is it tandem specific? Is there an upgraded bottom bracket available? Is this heat/friction related? We are taking the bike back to LBS next week. Just wanted to know if anyone had this same problem. Thanks.

TandemGeek

Unless there is a problem with the TruVativ ISIS bottom bracket -- not unheard of but certainly rare -- I would be more inclined to suspect a dry eccentric (the aluminum cylinder into which the captain's bottom bracket is installed).

Cannondales are notorious for noisy eccentrics and the only way to cure them is to fully disassemble, remove, clean, and then apply a generous amount of lubricant to the entire mechanism and contact surfaces on both the eccentric body and the frame's eccentric shell before reinstalling. It sometimes takes a lot of torque to get the eccentric tight enough to prevent creaking.

Of course, the other problem is getting the C'dale eccentrics loose -- particularly when they are dry. If you or your LBS ever have trouble removing the eccentric you'll find a "trick" to easy extraction here: https://hobbes.ucsd.edu/tandem/Maintenance.faq

The only other thing to check on would be the crank interface. ISIS and Shimano's Octalink spline interfaces require a healthy slathering of grease.

zonatandem

Cannondale was/is notorious for bottom bracket creaks. Years ago, friend with C'dale tandem had that problem; C'dale rep made the following suggestion: Remove pilot seatpost and pour a small amount of linseed oil down the tube. Miraculously, creaking ceased!

Bill G

ANOTHER METHOD FOR REMOVING A STUCK CANNONDALE ECCENTRIC

You can also remove a stuck eccentric on a cannondale by backing out the wedge bolts, take a rubber mallet and strike squarely againt the center of the crank arm on the opposite side of the wedge bolts dead center with the bolt that attaches the crank arm to the bottom bracket spindle. The eccentric will move to the side letting the wedged piece slide away from the eccentric body, therefore letting it slip or break loose enternally. This method will not leave any marks or dings if a good quality rubber mallet is used. Then grease the heck out of everything and reinstall the eccentric.

Good luck,
Bill G

zonatandem

Wedge bolt eccentrics have always been more problematic than others.

Old Hammer Boy

On my '05 'Dale, the factory used gobs of what appears to be Never Seez. I ocassionally loosen it up just to make sure it hasn't started to sieze up. It's been just fine so far. It may be that Never Seez has proven to be the best product for these wedge assemblies. You may want to use that in the future. Here's a link that describes the product's charteristics: https://anti-seizecompounds.com/product_02

Note that it resists galvanic action between dissimilar metals and also protects against road salt corrosion. I'm guessing these are the two main challenges with this type of bottom bracket eccentric. Good luck finding your phantom noise. OHB

TandemGeek

I previously recommend Anti-Seize compound... but most folks found it so messy to work with (your hands will look like the tin-man's from Wizard of Oz) that the added value vs. less aggressive lighter lubes was hard to justify.

Never Seez.. good stuff, but if you use it consider wearing disposable latex gloves and be prepared to clean the excess from your tandem following the install.

stapfam

I had to adjust the concentric at around 500 miles on my Dale and it took a bit of effort to adjust- Next time it had to be done was around 3,000 miles and that was difficult. Although I had greased it well- it had almost dried up. Since then I strip and rebuild it about every 1,000 miles and I put plenty of "Black Gold" grease on it. Wipe off the surplus, tighten it as tight as I can but at the 1K service it is very easy to free off.

redryder

Thanks for all of your replys. I printed off some copies for my LBS. The bike is in the shop and should be completed by Friday. We are planning a 50 mile ride Friday afternoon so I will see if the noise returns. Will keep you posted.

Thanks again

gregm

Creaks down there can also be attributed to chainring bolts or the pedal/crank interface. Something to keep in mind if the other possibilities don't pan out.

-Greg

wattage

Redryder,
I have a 2007 Cannondale road tandem with the same problem you describe. (The sound of ball bearings dragging intermittently on a dry bearing race)
We typically ride it once a week, 44 miles. The problem started around the 2000 mile point and it ALWAYS takes 35 minutes for the growling noise to start with a pattern very much related to the down stroke. It was obvious BB noise, but I did everything to remove other things from the equation first. While the noise does emit a similar frequency to say a chain grazing the front derailleur, it is NOT the front derailleur and fails in all 3 chain ring positions. The problem stops as soon as the pedaling stops, but of course everyone on the road wants me to fix my brakes. Right!
I have disk brakes, so just in case they are flexing and touching the pads, I adjusted the pads out so far the brakes would barely work, still failed. I had no doubts about this as the disk touching, say during a turn, produces a mush higher frequency ring, similar to a bell.
FYI... The BB noise also fails on any gear in the cassette. I have the TruVative Giga X BB’s, bearing cups are outside the frame “shell.” Replaced both BB’s and with great disappointment, 35 minutes into the next ride the growling (shh-shh) noise was back, only with a slightly different pattern and growl than before. Again, like your description, this is not a seat post creak or a pedal issue. Trying to stay open to new ideas, I swap the timing chainrings, front & rear, to have a different surface on the chain, even though there is waer on either ring. This also allows me to grease and TIGHTEN the timing ring bolts. Make note that I also removed, clean and re-lube both chains every time another part is changed through this whole process, just to keep everything super quiet.

I've had my wife un-clip so that only I'm pedaling, sound lightens, but it's still there and when we reverse the scenario with only her on the pedals, same problem. Since the timing chain allows me to put a load into both cranks, our next step was to remove the timing chain when the noise was at it’s best (out on a ride) and just have her pedal. Yup, it was quieter with only her pedaling, but the BB growl was still there.
Knowing new parts can be defective, even whole batches of a manufacturing run, I replace only the rear BB based on the last isolation step. 2nd new BB failed also, growl starts mildly 35 minutes into ride and grows to a very annoying gravel on metal sound by 50 minutes. New pattern, same noise. SRAM/TruVativ admits they have some issues to the dealer and sends us a new complete crankset, front & rear, with bearings and rings, the whole deal. I also replaced both chains during the process.

The very first 2 hour ride was sweet, no noise! 38 minutes in to 2nd ride, the growl started again and has been that way ever since. If I drop my head down toward the cranks when it's really growling, I can hear the noise being amplified through those big aluminum tubes as if it were a sounding board.
The fact that it always takes 35 minutes (+/- 3) before failing fits perfectly for grease in a bearing, fully warmed up. I have no doubt this is a drive train issue, but how many Truvativ bearings could be bad? I also have to believe this is compounded by some anomaly related to the aluminum Cannondale frame and tube size. I haven’t tried “Teflon tape” in the BB threads yet, but I guess I should.

So... did you ever resolve your issue? I'm at the point of going full Shimano cranks for $600!
Dan

Alex & Deya

We experienced the same issues with our C-Dale tandem, we replaced the eccentric for a better one as ours was old, the bb cups and bearings were replaced and the noise continued, after several tests our mechanic found that it was the skewers, also on our C-Dale the rear skewer mounts directly onto the rear derailleur hanger, after some use the hanger starts rubbing on the part of the frame that is mounted on. The sound really appeared to come from the BB as it travels inside the bike, we would re tight the rear skewer and the noise would go away for awhile, then it would come back after some use. Try taking off the derailleur hanger and put some grease between it and the frame, also try a different set of skewers. Hope this helps.

dubbelop

Funny - we have a 2004 Road Tandem with similar sounds as described in this thread. In our case it is not a BB problem since I replaced these last year with square-taper ones (got fed up with ISIS BBs failing after only a few thousand kilometers). Then what brings on this noise? In most cases it's in the rear hub, if you have a DT one. The 'ratchet mechanism' (the piece that gives you the clicking noise when freewheeling) on quite a few DT hubs is not properly made and can make beautiful noises once warmed up. There is actually a thread on BF on this subject but I don't remember the title of this particular one. A search should reveal which thread it is.

Good luck!

PMK

I realize many potential areas of creaks and noises are being noted. While this did not create a noise or grinding for our tandem, it could over time cause premature bearing failure.

One thing that is BB related that happened to our bike was BB fit. We have Race Face ISIS cranks and I installed new ISIS 118mm 4 bearing BB's made by Truvative.

When installed in our Speedster, everything was fine, smooth and free spinning.

We purchased another tandem, a Roadster that fit us better. During swap over to put the Speedster back to original and install the ISIS cranks onto the newer Roadster, the install went fine and per the book following torques and such. The problem arose in that the drivetrain never spun freely. Initially I wanted to believe it was the lower mileage wheels and freehub.

The drivetrain never freed up. I removed each chain and found the cranks not spinning freely. Upon inspection, it turned out being the BB cups would thread into the bottom bracket shell and bottom out on the threads. This then pinched the cup and bearing causing the bind.

The fix for us was I machined a few threads off the BB cups to eliminate the pinch and bind.

This was a BB problem and not a frame problem as the pinch occurred in not only the aft BB shell but also the eccentric.

I can't explain why the Speedster had no issue other than the steel frame having a thinner wall tubing than the aluminum Roadster.

Hope it helps someone someday.

PK

regomatic

We had similar creaky BB noises starting about 20 miles out ourselves just last w/e. Disassembly, thorough cleaning, greasing & reassembly of the self extracting cranks and crank to BB connection seems to have done the trick based on a short ride the next day.

The bike has about 6k miles on it since new. One friend, an engineer with pretty good "fix it yourself" skills said the BB was probably shot, throw it out & get a new one. The more experienced bike mechanic said it's probably not possible to wear out a decent quality BB in less than 12-15k considering the conditions we ride in & how we take care of the bike.