Knocking noise when pedaling

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Knocking noise when pedaling
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Posted: Apr 21, 2010 at 18:33 Quote
Well..i got my new bike all put together finally...But I hear a knocking noise whenever I pedal on the down stroke...i'm thinking it's maybe the BB but i'm not sure...or could it be something else?

I'm not totally sure..and it's bugging the hell out of me...it does it only sometimes too...sometimes it does it when i'm barely pedaling...but other times it won't do it at all....heavy pedaling or not...it just happens at random intervals..usually on the down stroke of pedaling though..

and yes i sued the search. but couldn't find anything.


Thanks,

Posted: Apr 21, 2010 at 19:01 Quote
sometimes that happens to me too. but i am not bike mechanic, so sorry can't help you on this

Mod Plus
Posted: Apr 21, 2010 at 19:09 Quote
I would check your chainring bolts first but make sure everything else is tight as well.

Posted: Apr 21, 2010 at 19:19 Quote
pipes10 wrote:
I would check your chainring bolts first but make sure everything else is tight as well.

iight thanx

Posted: Apr 21, 2010 at 19:39 Quote
Take it apart and check it out

Posted: Apr 21, 2010 at 20:30 Quote
I would check three places - just had this sort of noise bugging me on my bike, gawd its annoying:
• First the pedals - sometimes its just a rebuild or making sure they're tight. simple, easy, satisfying fix.
• Second the cranks - tighten chain ring bolts, check the fit in the bb, and if its a press fit spindle (this was the problem on mine) making sure there isn't anything funny going on there (loose spindle, uneven fit/spacing). My noise only came on the downstroke on my non-drive side only...so that narrowed it down pretty fast for me.
• Third, BB - is it torqued right? does the bb shell need facing (maybe its just a liiiittle off and creaking under pressure)

aside from that... any pivots or linkage bearings in the area? not likely the cause, but could happen.

good luck!

Posted: Apr 21, 2010 at 20:37 Quote
Going to sound ridiculous, but take your seatpost out and grease it. Or at least try it with the post out.

Its actually really common, and it makes sounds that sound like they come from the bb.

Posted: Apr 21, 2010 at 21:36 Quote
pipes10 wrote:
I would check your chainring bolts first but make sure everything else is tight as well.

i don't think it's that...because I made sure they were all tightened up before I even installed the chain and such...


I'll have a look tomorrow...I don't have a proper BB tool though...and I don't wanna take it to the LBS have them look at it pay for it..and have them tell me nothing is wrong...

I also just snugged up the crank arms...

pivots and such? well i noticed the rear most bolt on my shock was a tad loose..i sorta figured that was the problem..so I tightened it down..took it out for a test ride but the problem was still there...

it's kind of an eerie little problem...

I'll also try the seat post thing tomorrow. Thanks.

Posted: Apr 21, 2010 at 21:52 Quote
If its not just the bolt, but the shocks bushings being worn, then that could easily be your knock. Pinch your fingers around the shock eyelet, and fel for play between the eyelet and reducers while you lift up and set down the rear end of the bike. Not compress and release the suspension, but lift off the ground nd set down. Otherwise there will be pressure in the same direction on the shock if you dont, and that wont duplicate the situation that makes a bushing knock.

Posted: Apr 22, 2010 at 3:31 Quote
if it's only when pedaling, could it be your freehub? freewheels are notorious for 'knocking' and i suppose a worn freehub/cassette might do the same.

Mod Plus
Posted: Apr 22, 2010 at 5:34 Quote
debonis wrote:
i don't think it's that...because I made sure they were all tightened up before I even installed the chain and such...


I'll have a look tomorrow...I don't have a proper BB tool though...and I don't wanna take it to the LBS have them look at it pay for it..and have them tell me nothing is wrong...

I also just snugged up the crank arms...

pivots and such? well i noticed the rear most bolt on my shock was a tad loose..i sorta figured that was the problem..so I tightened it down..took it out for a test ride but the problem was still there...

it's kind of an eerie little problem...

I'll also try the seat post thing tomorrow. Thanks.

Even if it's something you don't think it is, check it anyways. Those creaks are hard to find at times and could be coming from a number of places. Best to do everything as bolts do come loose, especially on a freshly built bike.

Posted: Apr 22, 2010 at 8:32 Quote
On my Nomad I had a weird knock on the power part of the stroke. I did what everyone here suggested.

1. Pedals - a very usual and tricky culprit
2. Crankarm - next in line.
3. BB - still nothing
4. seatpost? - nope
5. headset - still a mystery
6. play in the cassette/rear hub - nada
7. pivots - gotta be the pivots right? - nope
8. bushings for rear suspension - worn out by a mm !!!!! This was the answer.

Good luck dude.

Patrick

Posted: Apr 22, 2010 at 14:01 Quote
Well went through the bike...found a couple loose bolts tightened them but wasn't the problem...then occured to me that it might've been the rear wheel...so I swapped out wheels....and what do ya know.....the knocking went away...so I'm either gonna get a hub rebuild...or just swap wheels and cassettes...

I like the Alexrim DM24 though(my current wheel causing the knocking)...so i'm more leaning towards a rebuild...my other option is my Mavic 321...which is off my old Kona..

Posted: Apr 22, 2010 at 19:35 Quote
if the knocking is coming from your wheel my guess is it's the freehub body, not necessarily the cassette itself. swapping cassettes might help but could lead to other issues on a used drivetrain, if everything is new i see no reason the cassette could be making the noise especially if there is no play in it already.

Posted: Apr 24, 2010 at 20:01 Quote
gordanfreman wrote:
if the knocking is coming from your wheel my guess is it's the freehub body, not necessarily the cassette itself. swapping cassettes might help but could lead to other issues on a used drivetrain, if everything is new i see no reason the cassette could be making the noise especially if there is no play in it already.

it wasn't the cassette it was the freehub...I just swapped rims and cassettes on the two rims...so now my Mavic 321 has a 8-spd instead of the 9-spd it had before...the 8-speed which was originally on the bike...I guess you could say it was the...one freehub? lol (lame I know lol)

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