Hard to find/fix noise
 

I have a 2005 Co-Motion Primera Co-Pilot that in the last year or so, has developed a subtle squeak that is driving me nuts. It has an FSA Gossamer crank set with ISIS bottom bracket. Our cranks are 90 degrees out of phase. Here’s a description of the sound:
• Noise is a low scraping/squeaking/shushing sound
• Usually starts 25 to 30 minutes into a ride
• Occurs only when pedaling
• Sounds like it’s coming from the drive train, seemingly the front bottom bracket
• 2 squeaks/scrapes every crank revolution, corresponding with alternate leg power strokes
• Seems to be worse in warmer weather
• Can’t be duplicated on work stand
• Continues when out of saddle
• Will momentarily stop after shifting on the rear cog, then will start again
• Occurs when pedal pressure is medium to high, not flat cruising or grinding up steep hills

Here’s a list of things I’ve done to try to diagnose and correct this:
• Tightened chain ring fixing bolts
• Lubed chains. Chains have minimal stretch
• Disassembled both bottom brackets multiple times, including front eccentric. Lubed all threads and mating surfaces. Thoroughly tightened cups
• Replaced bottom bracket cartridges
• Tightened seat post clamp bolts
• Lubed & tightened S&S connectors
• Teflon taped bottom bracket & pedal threads
• Tightened all handlebar stem bolts
• Disassembled cassette, lubed mating surfaces, reassembled & tightened lock ring securely
• Tried different pedal systems (alternated Egg Beaters & Look)
• Tensioned all rear wheel spokes
• Lubed & tightened crank arm fixing bolts
Any suggestions?
Thanks

Is a wheel flexing resulting in a brake shoe rubbing? Is a wheel flexing resulting in noise at a point where spokes cross?

Suggest removing both chains and minutely inspecting each link looking for damaged sideplate.

i'll suggest the simple & ridiculous: try fiddling with your quick release skewers. a dab of oil here or there in the lever mechanism, take skewer out completely, re-assemble, and re-tighten it. you might be amazed that it just might be the culprit. it's happened to me on a few occasions.

other than that, i can rattle off about a couple of dozen or so things....but you got most of 'em...

others: have you greased (with thin film of grease or carbon paste if you've got carbon-railed saddle) the seat rail/seatpost interface? also, remove & re-grease H20 bottle bolts. try a tiny drop of oil on each spoke nipple. is there a very thin film of grease or carbon paste (depending on fork steerer composition) between anything that clamps to steerer? same question for bar & stem.

i feel your pain, i hate creaks, especially when they sound like they're coming from one spot, but something totally seemingly unrelated is the root cause!

Probably a Poltergeist. These things are very difficult to get rid of.

If you've already gone through the drive train & saddle, check your shoes.

When you had your rear cassette off, did you also pull off, clean and re-lubricate the freehub?

I don't think your hubs have adjustable bearing pre-load, but you might also check the axle nuts to make sure they're tight and that there's no excessive axle play.

I had a squeak sort of like that, turned out the captain's seatpost needed to be removed and anti-seized. You might lube the eccentric while you're at it.

Might read some of these other posts.

http://www.bikeforums.net/showthread...hlight=bad+hub

Like TG, I'd give a look at the rear hub seeing all you have done already.

PK

Thanks, everyone, for your thoughtful suggestions.
Some feedback on my part:
• I’ve tensioned all the rear wheel spokes – that doesn’t seem to be the problem. I have a rear disc brake which I’ll pay some more attention to, but that doesn’t seem to be the problem either.
• Both chains will be due for replacement before too long. Maybe that will help, although it’s hard to imagine the type of noise a circumstances it occurs coming from the chains. Why only after a warm up?
• I’ve actually tried the “ridiculous” suggestion of lubing the quick release. Didn’t help, but I’m going to try it again anyway.
• Our saddles are retro – San Marco Rolls and Brooks women’s B17, so no carbon fiber rails. I’ve tightened the bolts and lubed the pivot points on the stoker’s Thud Buster post. During the winter overhaul, I essentially disassembled and reassembled the whole bike, greasing all the threaded connections.
• I’ve tried riding with my walkable shoes and Egg Beater pedals and a pair of road shoes and Look pedals – no difference.
• The one thing I haven’t done is disassemble, lube & reassemble the rear hub. The noise doesn’t sound like it’s coming from back there, but I’m running out of options. I did notice in an older post that the back wheel was the cause of a similar problem. Hope to get this done next week.
• Has anyone had persistent noise problems with the front eccentric? I’ve had mine out numerous times & lubed it to no avail, but I’m still suspicious of it.

All good, but pull and lube both posts.

A friend of mine had such an issue with his Cannondale tandem.

After trying the obvious and not-that-obvious (the list is rather long), we found it was his Hügi's freehub body's bearing cartridges squeaking against the axle.

He was in the middle of a trans-America (and back) trip so we didn't have the chance to order and replace the axle and bearing cartridges. Instead, we just lubed the cartridge/axle interface.

The fix was good enough to last from Montréal to Nashville on a fully loaded bike.

What rear hub do you have?

I'd clean and relube maybe even replace your derailleur's upper jockey pulley. That's supposed to have a tiny amount of float built into it so it acts a little bit differently immediately upon shifting and once it's had time to settle itself. Ironically, the float is supposed to make it quieter.

We had a similar sound that would come and go, replaced freehub on Rolf wheels, so far, so good.

My bet is it's the B-17 rails squeaking. I've got the same problem on one of my bikes and see is as part of the saddle's "character".

I may have found & fixed the problem. Not sure because I’ve been wrong with this quite a few times and the noise can range from annoyingly obvious to very subtle. Yesterday I disassembled the rear hub (DT Swiss 540), cleaned the guts and lubed the star ratchets. Seems like a long shot, but today Linda & I rode 27 hilly miles with no squeak. I lubed the ratchets with Phil Tenacious Oil because I don’t have any of the DT Swiss special grease that the manual recommends. Anyone know anything about that grease? Where do you get it?

If this does fix the problem, it shows how difficult it is to locate where a sound is coming from. It distinctly sounded like the front bottom bracket. Sometimes I could hear the sound clearly, but my wife couldn’t. If the noise was coming from the back wheel, that escapes logic.

Thanks for everyone’s suggestions. I tried all those that I had not experimented with already.

For all of our tandems, the DT 540's are lubed with Phil oil. I have the specified grease but the Phil oil is easy to use and for our off-road tandems there is minimal chance of the molykote grease slowing the engagement.

With the oil, it seems about every 1000 miles I remove the freehub and relube with a few drops of oil.

PK

That would be the freehub... it's a regular maintenance step that many cyclists don't attend to. The DT hubs are very unforgiving of the lack of freehub / star ratchet maintenance and relubrication.

As for the migration of sound on a tandem, it can often times be very daunting. You will swear a noise is coming from the front of the bike, and son of a gun if it's not coming from under your seat. Same thing with rear hub noises migrating to the boob tube.

Glad that you've found it... gremlins are annoying to be sure.

These hubs also do not like a lot of the DT specific lube, Molykote, as it can prevent tight engagement of the drive rings. As the TG said, this is one item that many times should see more maint than they actually get.

PK