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Intermittent knocking noise after replacing components

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Intermittent knocking noise after replacing components

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Old 09-02-12, 04:11 PM
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Pickleballer
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Intermittent knocking noise after replacing components

I have replaced the rear wheel, the freewheel and chain on my 1989 TREK 1400. I am having an intermittent knocking noise since I have done this. It ony happens when I am peddling. Does anyone know what could cause the knocking?
There was no knocking before I replaced these components.
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Old 09-02-12, 04:38 PM
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Depends on how intermittent, and whether it's rhythmic or random. If it's fairly steady happening every 2-3 pedal revolutions, I'd suspect a stiff or damaged link in the chain.

Otherwise if it's more like every pedal revolution it could be bottom bracket play, but if you didn't have it before and didn't touch the BB, hold this as a last resort.

More random noises, might simply be that you didn't tighten the cassette lockring enough, or that the cassette didn't overhang the freehub body, so the lock ring isn't compressing it properly. Stick a spoon between 2 sprockets, and see if you can lever them apart slightly. If so the cassette isn't tight.

That's just the simple obvious stuff for starters, check that, and come back with a better description of the sound, and it's frequency of occurance, ie random, once per pedal revolution, only when under load, etc. and we'll give you more things to check.
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Old 09-02-12, 04:58 PM
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It is not a cassette, it's a freewheel. The reason for replacing the wheel was to convert the cassette to a freewheel. The cassette that was on the bike had a threaded small cog instead of a lock nut. I couldn't find that type of cassette to replace it. It's a 7 speed. I have been working with the chain, putting oil on it and it seems fine.
The knocking happens everytime I pedal for a while.... then it quites fo a while.... then it starts again. I've ridden the bike over 200 miles since I made the changes and it continues doing it everytime I ride. I only have one chain ring on the front. I'm thinking about reversing the chain ring and see if that is the problem.
The bottom bracket seems tight and smooth. Doesn't seem to be a problem there.
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Old 09-02-12, 05:48 PM
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Originally Posted by Pickleballer View Post
It is not a cassette, it's a freewheel. The reason for replacing the wheel was to convert the cassette to a freewheel. The cassette that was on the bike had a threaded small cog instead of a lock nut. I couldn't find that type of cassette to replace it. It's a 7 speed. I have been working with the chain, putting oil on it and it seems fine.
The knocking happens everytime I pedal for a while.... then it quites fo a while.... then it starts again. I've ridden the bike over 200 miles since I made the changes and it continues doing it everytime I ride. I only have one chain ring on the front. I'm thinking about reversing the chain ring and see if that is the problem.
The bottom bracket seems tight and smooth. Doesn't seem to be a problem there.
OK, so it's a Frankenbike. What was removed and reinstalled? If it's only got one chainring, are the chainring bolts all the correct length, with greased threads and tightened properly?

Did you remove the pedals at any point? The noise you describe might be a wiggely pedal- take both of them off, clean the threads, apply fresh grease, and reinstall tightly.
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Old 09-02-12, 06:09 PM
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Since the wheel is also new it too can be suspect. Could be bearing play, axle movement or any number of things. More info is needed to narrow the possibilities.
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Old 09-02-12, 06:14 PM
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I suspect that something snuck into your frame while it was opened up
and now wants you to let it back out...............

Honestly, these "I have a mysterious noise" threads, while no doubt started
in good faith by the posters, are as impossible to answer as the "why is
there air in my tires ?" threads.

OP, please think about it. A bicycle can squeak, knock, rattle, or click
anywhere two parts come together........... there are a lot of parts.
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Old 09-02-12, 06:33 PM
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I'm going to try a friend's rear wheel on my bike and see if I can narrow it down. I'll just keep changing things until I solve it.... hopefully.
Thank you for all the suggestions and comments.
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Old 09-03-12, 10:52 AM
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I'm gonna guess that it's the freewheel. Some of them have enough play to knock a bit. It is always intermittent. Next time it happens, try spinning the cranks backward one revolution - see it it stops.

This is a common problem on the SS BMX type freewheels.

-G
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Old 09-04-12, 03:23 AM
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Yesterday I switched rear wheels with a friend. We rode the bikes about 5 miles and neither one of us heard the knocking noise. The knocking usually starts up right after I start riding so we thought 5 miles would be enough to test it.
I have pedaled backwards and that didn't seem to help either. I saw someone suggest doing that in another thread in case the chain had a stiff link.
Tomorrow my friend and I will switch the wheels back and see if the noise comes back.
Thanks for the suggestion.

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Old 09-04-12, 06:35 AM
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Originally Posted by gmt13 View Post
I'm gonna guess that it's the freewheel. Some of them have enough play to knock a bit. It is always intermittent. Next time it happens, try spinning the cranks backward one revolution - see it it stops.

This is a common problem on the SS BMX type freewheels.

-G
^^^ With high certainty, I'd say that this is your issue. You may be able to quiet the freewheel by removing it, soaking it in a mild solvent (like mineral spirits), spraying in a solvent with force (like wd-40) into it and spinning it, then re-lubricating with a synthetic motor oil. Pour it in the outer rotating seam, and let it drain outward. Wipe clean thoroughly and re-mount on your wheel. Let stand overnight with a cloth beneath the freewheel (keeping remnants of oil from dripping onto your rim), wipe again and you should be good to go.

By the way, sounds like you has a Uniglide Shimano cassette. You need to chain whips to remove them - instructions are on the web. These cassettes can be found on eBay for relatively cheap, so you could re-use the original wheel if you wanted... PG
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Old 09-04-12, 04:24 PM
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If none of that works, read this and maybe something will ring a bell: Keep it Quiet
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