# knocking sound coming from rear wheel.



## RLX (Oct 6, 2004)

I have a Cannondale r4000 and have notice a knocking sound that comes and goes. It sounds like it is coming from the rear wheel. Any clues on what it could be? Rear hub going out? bearings? I have only just a little over 1000 miles on the bike.
Any help would be appreciated.
Rob


----------



## wim (Feb 28, 2005)

Start tracking the sound down methodically: Does the sound stop when you stop pedaling? Do you hear the sound in every gear or not? Can you hear the sound when standing next to the bike, lifting the rear wheel off the ground and spinning it? And so on -you get the idea. Find as many variables as you can and check them off one by one.

Get back with us if you still can't locate the source of the noise after doing this.


----------



## Juanmoretime (Nov 24, 2001)

*Sounds like?*

Not all sounds are necessarily coming from where they sound like where they are coming from. I had a creaking sound that I swore was coming from my chainrings, it wound up being a front skewer that I just needed to tighten a little more. I had a creak just the other day that, once again, sounded like it was the chainring, but it would only happen in one cog on the cassette, I pulled my rear wheel and it wound up being that the cassette lockring wasn't as tight as it should be. The creak is now gone. I also once had a sqeaking sound that I thought was my saddle, I replaced the seatpost and, once again, sound gone.

Do some detective work and you will find the source of the sound although it may not be where you think it's coming from.



RLX said:


> I have a Cannondale r4000 and have notice a knocking sound that comes and goes. It sounds like it is coming from the rear wheel. Any clues on what it could be? Rear hub going out? bearings? I have only just a little over 1000 miles on the bike.
> Any help would be appreciated.
> Rob


----------



## roger027 (Aug 10, 2004)

*This may help*

I noticed a "knocking" coming from the rear end a couple weeks ago. I only heard it when I was pedaling, so I focused on the cranks, pedals, chain, cassette, hub and found nothing. Then I checked the pulley bolts on the rear der. and found that the top pulley wheel was loose. Tightened the bolt and sound is gone. Hope this helps.


----------



## RLX (Oct 6, 2004)

It only makes that sound when I pedal....I will check to see if it comes in all the gears.
I will start the investigation today and do some detective work!
Thanks everyone for your help.
Rob


----------



## Al1943 (Jun 23, 2003)

RLX said:


> It only makes that sound when I pedal....I will check to see if it comes in all the gears.
> Rob


Possibilities:
tight link in chain
end of saddle rails where the saddle attaches
loose bottom bracket
computer magnet
brake pad hitting rim joint
loose spoke


----------



## Dave_Stohler (Jan 22, 2004)

Derailleur hitting spokes because of a bent hangar? 

Crank hitting chainstay??


----------



## funknuggets (Feb 4, 2004)

*My stupid teammates in college...*

Would pull goofy tricks like put ball bbs down your seat tube, or switch out your spare tubes with tubes that had bbs in them, and repatched. Goofy ba$tards... the bbs in the seat tube took me forever to figure out.

So, you don't ride with any guys in their mid 30's from Missouri do you?


----------



## Gregory Taylor (Mar 29, 2002)

*Other Stuff to check for --*

If it is a heavy knocking, I'd check for these as well --

Wheelbearings loose? Take the wheel and rock it from side to side and see if there is any play in hub bearings.

Loose cassette? Sometimes they can make noise if they don't fit just so on the freehub body, or the lockring is loose.

Loose bottom bracket? Take the crank and try to work it side to side with your hands. 

Headset loose? Squeeze the front brake and rock the bike back and forth. Is there play in the headset?

Are you pedaling squares? Sometimes you can get a "clunk clunk clunk" sound if you are not pedaling smooooothly. Some hubs let you know in no uncertain terms when the freewheel engages. 

Saddle rails -- these can make an awful racket if they are loose. Unbolt the saddle, shoot some lube on the seatpost head where the saddle rails are clamped, and retighten.


----------

