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Old 01-17-03, 04:29 PM   #1
jmlee
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Tock, tock, tock sound--A mystery

I am getting a “tock, tock, tock” sound out of the back half of my bike. It occurs only occasionally, and never lasts more than about 5 seconds at a time. It beats in rhythm with the turning of the rear wheel, but it stops if I stop pedaling. For a while today, it would “tock, tock” for a few seconds, then quit for about 10-15 seconds, then return (I was pedaling the whole time).

The bike is a 1983 Trek road bike (Reynolds 531), with Suntour Superbe components. The wheels date from the late 1980s, but have only about 7,000-10,000 miles on them. They have sealed bearing hubs (Mavic), with a 6-cog threaded freewheel (Shimano-recent purchase). The chain is probably nearing replacement, but neither it, nor the derailleur, nor the cogs appear worn or bent.

I also currently have fenders on the bike, but I have carefully checked that nothing is close enough to rub. As near as I can tell, everything else is in order—no rubbing, or parts knocking together. A friend said he thought it sounded like rubbing sound, but I think it sounds more like a “tock, tock.” I would almost say it sounds like the "ping" that spokes will make as they seat themselves on a freshly-built/overhauled wheel. But, yes, the wheel is true, and the spokes have even tension.

To me, it’s a mystery. Any clues???

With my many thanks in advance,
Jamie
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Old 01-17-03, 04:43 PM   #2
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I had a broken sideplate on a chain that caused something like that.Got a workstand you can put it in and look and listen while turning cranks?
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Old 01-17-03, 04:45 PM   #3
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Bottom bracket loose? Seat rails? Crank bolts tight? Hopefully not a cracked frame.
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Old 01-17-03, 05:58 PM   #4
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I'd say that it is something like....
when you put pressure on your crank, it will pull your whole wheel to one side very slightly (depending on which pedal you are pushing on at the time will change which way it pulls). A very high quality wheel that doesnt use the 'cone and cup' system in the hub wont do this.

Therefore i think that the tyre could be catching on your frame at the closest point to your tyre/ rim, or any other obstacle like your brake.

I have had a similar problem when I had a wheel with loose cones, it kept being pulled over to the side which was making it catch on my metal brake booster (magura hs33).

Put your bike in the stiffest gear you have and somehow put plenty of pressure on any pedal, then get someone to check around your rear wheel for anything catching.

If that doesnt solve it- put your wheel in someone elses frame.

Hope it works.
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Old 01-17-03, 06:40 PM   #5
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Check all the areas mentioned before.


Also, check the headset. It sounds silly but I have seen a bad or loose headset creat a noise like what you described and do to the material of your frame the sound will resonate towards the back.

Slainte
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Old 01-17-03, 07:08 PM   #6
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threadend: oooh, oooh, oooh pick me jmlee, I know! I know! pick me, pulleeze pick me
jmlee, after looking about the forum for another volunteer: Yes, threadend?
threadend It's a dry interface between your seatpost and seat tube
jmlee: What makes you believe that's what it is threadend?
threadend: just a hunch jmlee, but I drove myself crazy for 2 weeks once, tightening, tensioning, listening, disassembling / reassembling, feeling my bike, hearing and then not hearing an evasive, rythmic, inconsistant sound just like you are describing. Finally, in desperation I pulled out my seatpost and lubed it. the sound went away.

Unless you have a carbon fibre seatpost, then,uhm, nevermind.
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Old 01-18-03, 04:18 AM   #7
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Hmmm... lots of interesting ideas here.

Pokey: I have checked the bike in a workstand (which means here a piece of rope over a beam). I *cannot* reproduce the sound no matter what I do: shifting to all gears, holding the back brake in various positions, even pushing on the fenders a bit. The fender clearance at the brake is narrow (about .5 cm), but the narrowest point is the center of the wheel. The clearance is almost 1 cm on the sides.

I don't think it is in the bottom bracket (which is sealed, BTW). I just scrubbed down my chainrings and the BB and cranks all seemed in order (yes, the sound was there before this maintenance). I suppose I could pull the cranks off and check whether I feel any scraping. Also, as I said, the sound occurs in rhythm with the turning of the wheel--although I have to be pedaling to hear it.

I will also inspect the headset, and the seatpost. Those are both odd, but not infinitessimally small possibilities.

Cracked frame? Geez, I shiver at the thought. But, to figure that out, should I do more than a visual inspection? BTW, this is a steel bike, so the typical Al cracks are not very likely.

I suppose that the next best thing that I could do, is to take the fenders off and see if I still get the sound. That would rule out the scraping possibility.

Any other thoughts?

Thanks again,
Jamie
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Old 01-18-03, 08:38 AM   #8
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I had the experience before but I'm not exactly sure where that comes from. Anyway, when I hear the sound, I know it's from the bottom bracket because that's the source. However, I'm not really sure whether that's the problem area because the sound might travel from some other parts.

It seems to be gone after like I lube the various areas of my bike. Now, it's almost silent.
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Old 01-18-03, 08:34 PM   #9
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I assume that there are not any broken spokes in the rear wheel? Also be sure that the derailleur hanger is straight so that it does not ping the spokes as the wheel goes round. If all is well there then try putting a drop of oil at each nipple where it enters the rim and where the spokes cross each other, sometimes as the wheel is loaded in certain ways the spokes rub on each other and make noise. If you have a reflector on the wheel take it off - sometimes they cause noise. Spoke protectors (the frisbee shaped thingy behind the freewheel or cassette) can also make noise if they are installed improperly or are broken so check that too. Good luck.

-Ryan
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Old 01-18-03, 09:26 PM   #10
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My best guess is what BikerRyan is talking about. Sometimes a bushing, where the spokes enter the rim, will work loose and click once a rev. But it's more of a "tick" than a "tock." But, in my experience, it happens regardless of whether you pedal. If you think that might be it, you can mount the bike on a workstand, and go around the wheel squeezing pairs of spokes (like you were stress relieving them). Go forward and reverse a few times until you isolate it. If that's it, you can silence it for some period of time by dripping some oil in and around the bushing. It's best to lift the rim tape and lube there, too. Or you can leave it alone... it doesn't mean the rim is failing or anything, just can be annoying.
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Old 01-19-03, 08:28 AM   #11
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ucheck and lube your clipless pedal platform.

i know. i know. but if you can't reproduce it on a 'stand' then it is either a spoke on the non-drivetrain side or this.

all thoughts on this thread are viable
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Old 01-19-03, 06:22 PM   #12
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Quote:
Originally posted by BikerRyan
If all is well there then try putting a drop of oil at each nipple where it enters the rim and where the spokes cross each other, sometimes as the wheel is loaded in certain ways the spokes rub on each other and make noise.
Ryan,

Talk about coincidence! Last night at our bike club's awards banquet we were talking about creaking spokes. The guy across the table suggested exactly what you suggested. The funny thing is that the guy's name was "Ryan". Since this was in California, it probably wasn't you.
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Old 01-20-03, 04:13 AM   #13
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I agree, all possibilities mentioned here are worth investigating. Curiously enough, I did a 107 km group ride yesterday and I only heard it a couple of times at the end of the ride. (Although, I was worn out from MTB the day before and intervals the day before that--so I was listening more to my pain than my bike.)

I think that I'll start with the fenders as I mentioned--but my time and the weather may limit my ability to test it in the next few days. In any case, I'll let you all know what it was when I figure it out.

But, for now, thanks for all the good suggestions.

Cheers,
Jamie
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Old 01-20-03, 04:14 AM   #14
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Hi JMLee

I had a similar problem about a year ago, which turned out to be severe pitting of the cones in the rear wheel bearing. One would expect this to have made noises all the time, but it took the extra forces due to pedaling to provoke it. This is what confused me, before I found and fixed the problem I'd checked the cranks, chainwheels, had the bottom bracket changed, looked at the saddle and seatpost...

Just a thought,

Ed
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Old 01-20-03, 02:14 PM   #15
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Try changing out the rear wheel for another and ride it.

My bet is on a couple of suspect spokes.
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Old 01-21-03, 05:31 PM   #16
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You see 'Ed Holland' says the same as me!
I reckon thats what it is, check your cones, and push hard on your cranks, ask someone to look closely whilst you are doing it.
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Old 01-22-03, 07:15 AM   #17
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I had a similar problem a few years ago. And after days of trying to figure it out, I discovered that the Quick Release on the rear wheel wasn't as tight as it should have been.
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Old 01-24-03, 11:18 AM   #18
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Well, I removed the rear fender and went out for a good 50 km this afternoon....

There was silence in the courtroom as the judge asked the foreman of the jury to read the verdict: "We the members of the jury have found the accused rear fender to be innocent as charged."

For the first 35 km, I heard nothing, but in the last part of the ride the sound reappeared in its usual occasional way. I am going to tear apart the cranks and BB, since that seems to be where the sound is coming from.

This is a sealed BB, so I am not sure what to look for. When I installed it years ago, I was joyful that I would not have to deal with my BB for a long time. Any advice?

And, any thoughts as to why the sound only appears after about 35 Km (this fits its earlier behavior)?

Cheers,
Jamie

P.S. It is amazing what one finds when one removes fender. I decided to inspect the rear tire for any signs of funny wear (coming from the much maligned (not to say misaligned) fender. I found about 4 sizeable cuts in the tire, including one with an offending piece of glass still wedged in it. When I pulled the tire off to inspect the inside, I found that the glass had pushed through. I am amazed that I didn't get a flat. Needless to say, I decided to retire this Continental (which has a good 4000 km on it--not too bad for a rear tire, treadwise I could have squeaked another 1000 out it perhaps).

Last edited by jmlee; 01-24-03 at 11:28 AM.
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Old 01-24-03, 12:07 PM   #19
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Quote:
Originally posted by jmlee
This is a sealed BB, so I am not sure what to look for. [...] Any advice?
I don't think it's the BB, since you said the frequency was once per tire rev. But, since you're looking at it, before removing it, make sure it's solidly in place by tugging back and forth on the cranks pushing/pulling perpendicular to the bike frame, and in several positions. There should be no play, and no creaking/clicking. Then, after the cranks are off, but still snug in the frame, rotate the spindle. Should be smooth and rotate reasonably freely. Likewise after the unit is removed from the frame.
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