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Old February 18th 19, 12:05 AM posted to rec.bicycles.tech
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Default Tracking Down BB Noise

On Friday, February 15, 2019 at 12:35:03 PM UTC-8, jbeattie wrote:
On Friday, February 15, 2019 at 11:06:34 AM UTC-8, wrote:
On Friday, February 15, 2019 at 9:38:00 AM UTC-8, jbeattie wrote:
On Sunday, February 10, 2019 at 7:57:28 AM UTC-8, AMuzi wrote:
On 2/9/2019 6:34 PM, jbeattie wrote:
Rule of thumb -- when you have a BB noise, start with the rear axle drop-out interface. I ignored the rule of thumb trying to track down what was clearly (in my mind) a BB problem -- a light thunk every time the left pedal arm hit the bottom of the stroke. This was on my Synapse with an OE Cannondale SI crank -- a pretty simple crank with a SRAM-like interface (bolt on arm and not pinch bolts like Shimano). So, I get out my jumbo 10mm hex socket to remove the bolt/cap, pull of the crank with a kludged Park remover (long story), check the bearings -- and they're fine. Grease everything up, re-assemble, go for a test ride in the snow, and it's still thunking. I get off the bike, rock the crank, and I can produce the same thunking -- but I don't really feel play in the crank, but I figure its moving laterally and needs another shim. Pull the crank again and put in a .5mm shim. Still thunking. Back onto the stand. The bike has a 12mm through axle rear hub (HED), which I had tighten
ed earlier to rule out any issue there, but what I didn't notice is that the hub axle end cap had come loose, which allowed the hub to move laterally. Pull out the cone wrenches, tightened it up and thunking went away.. A five minute repair. I don't know how or why the end cap loosened, but I've had the same problem on other wheels with similar thread-on end caps.

-- Jay Beattie.


+1
Not just through-axle.
Dry QR cams make the same noise because you think the wheel
is secured but it's not.

My commuter was making a ton of racket yesterday -- BB noise like I was rocking in a bamboo rocking chair. I reset the QR on the rear wheel and oiled the chain, and it all went away. A dry chain can make a lot of noise, too. With all the rain, the lubricant gets flushed off my chain pretty quickly.

-- Jay Beattie.


According to Zen you're too stupid to ride a bike if your chain starts making noise.

According to me the weather changes mean that you have to find the correct lube for the weather. I have an entire shelf full of different lubes and they all react differently to weather. Rock and Roll doesn't work in the cold and the Ice Wax does.


The correct lube for long periods of rain is whatever I have sitting next to the garage door. Expensive wet-weather lubes are just applied less often, but all lubes do about the same thing. This is a commuter, so I'm not in the rain for hours at a time or looking for the last word in low friction, and I can just spray or drip something on the chain before leaving in the morning. This morning it was ATB because there was a bottle knocking around.

-- Jay Beattie.


Well, I was using the Rock and Roll which is a high Teflon lube that you put on and leave a day and everything is dry and the chain doesn't pick up dirt and you normally get a really quiet chain.

But the noises I was getting were really difficult to trace. I think that my hearing is getting poor enough that I don't have binocular hearing any longer. I'll never be DareDevil.

In any case the Snow Wax stopped all the noise that sounded to me like a bottom bracket or left crank or pedal.

One of the weaknesses of these newer wheels is that their demand for lighter weight means that the end caps on the quick releases are made out of aluminum and it is very difficult to get them tight enough not to slip in the horizontal dropouts of the older bikes. So rather than noise coming from the rear dropout I get the wheel pulling over and rubbing against the off-side chain stay.
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