Hi All,

My carbon fiber road bike has developed popping and knocking sounds that are driving me crazy. I've looked the frame over and don't see any cracks and the bike rides and shifts smoothly. Here's what I've checked/done so far:

1. Tightened chainring bolts.
2. Cleaned seatpost and seat, greased seatpost rails, seatpost bolts, and seatpost collar bolts (Thomson seatpost and collar).
3. Checked bottom bracket and headset for play by rocking back and forth.
4. Squeezed spokes to check for looseness.
5. Removed, cleaned, reinstalled cassette.
6. Greased and reinstalled bottle cage bolts.

Everything looks good as far as I can tell. Prior to this there had been an intermittent clicking when seated with each pedal stroke that is now gone and apparently morphed into this much louder sound. It's the worst when pedaling slowly under load. Less frequent when out of the saddle or coasting (but still happens), but doesn't seem to happen when coasting downhill at speed. If anyone has a clue or suggestion I would appreciate it. The LBS is 1.5 weeks out on repairs so it's much if I can sort it out myself.

Chris

Haha. There are two new posts within 15 minutes of each other with the same problem. Check your skewers, maybe add a light film of grease to the skewer. Check your stem (bars and steerer clamp) as well, and if you have carbon paste, add some to the stem and seat post.

You haven't mentioned pedals or shoes. Swap your pedals with a known-quiet pair, preferably platform type to eliminate shoe/cleat noises. Clean and grease both pedal and crank threads and their mating surfaces and torque properly.

I had a BB bearing go south recently, & it made noises like that.

The (BB30) retainer clip had broken, & pieces would intermittently get crunched past the balls.

The crank still turned pretty smoothly on the stand.

The noises can still be heard when not pedaling/coasting, and have gradually gotten worse. Sounds to me like the wheel bearings and/or cone nuts have become pitted.

Dan

There are a couple common causes of creaks and pops.

Many newer bikes have press-fit bottom bracket bearings that are prone to creaking. I have no experience with these so can offer no advice. If you have a threaded bottom bracket make sure it is good and snug in the frame. You would have to remove the cranks to do this. As you pull the cranks off, listen closely as the interface between crank and bottom bracket spindle can also be a source of noise, usually noise that occurs regularly with crank revolutions.

The seatpost interface witht he frame and the saddle interface with the seatpost are often culprits, but if you cleaned and retightened then it's likely not that.

The most insidious cause, often making a very loud and annoying noise that is extremely difficult to diagnose (but dead simple to fix) is the cable housing ends in the cable stops on the frame. IF there is corrosion or debris in the cable stop it will make a creak noise with any slight movements of the handlebars, and this noise echoes through the frame. To fix this, first try pulling the cable housings out and wiping down the ends of the cable housings and the inside of the cable stops. The noise migh also be from inside the cable ferrules (cable housing ends caps) if the ends of the housing are not cleanly cut.

Thanks all, and a quick follow up. I tried swapping out to an old pair of pedals and went down the driveway in my loafers and the noise was still there. I also swapped out to a seatpost/seat from another bike and still had the noise. I road down the driveway and today heard the popping/crackling really ramp up when I stopped pedaling and coasted down the driveway. This is driving me mad! I had the bike completely overhauled in Feb.

If the noise occurs when coasting can it be the BB? If it is the BB, I would think if it would only happen when pedaling.

Thanks, Wilfred for the suggestion about cables. I'll check it out. It does sound like whatever it is it is echoing through the frame.

I'm still going to ride it. Can't be home day after day and not ride.....

Chris

Follow up to my follow up. I listened to the rear wheel and there is some noise there, a faint clicking which sounds unusual. Maybe the bearings or cone as ForceD suggested When I am on the bike could the added weight cause the sound to be transmitted to the frame and echo?

Noises travel well in a bike frame. The sound usually isn’t coming from where you think that it is coming from. Keep doing what you are doing. Check one thing at a time, and try again.

Bike noise drives me crazy, but you get better at diagnosing with time and practice.

Got it. It's coming from the rear wheel. It is amazing how a little grinding noise from the hub due to bearings or mis-adjustment is being amplified by the frame. It sounds like the carbon is fracturing apart! Now, onto the hub....

Just want to reiterate...you said you are hearing the noise when you're NOT pedaling. Therefore...how/why could it be the pedals or BB? Usually, when cones/bearings have gone bad the "popping" or grinding noise they make won't be heard when spinning the wheel when the bike is on the work stand. But, as you point out, will be heard while actually riding. Take the cassette off, disassemble the rear hub, and check the cones/bearings. I will bet they're pitted and need to be replaced.

Dan