Mike’s (Noisy) Bike

By Jim Langley

Almost with the dawn of the Internet, in 1998, I started a cycling website. I don’t get to work on it anywhere near as much as I should or would like to. Yet, it has still swelled to more than 200 pages of what I like to think is helpful and fun bike stuff.

One of the most popular pages on my site is my Keep It Quiet resource, literally thousands upon thousands of words on finding and silencing the clicks, creaks, clunks and things that go bump on your rides from your bicycle – and drive you bonkers.

Lots of the most interesting noises and solutions have been contributed by roadies like you; thank you. I add them to my page along with the new ride-ruiners I discover and shut up.

So you’d probably think I could find a noise when I need to, right?

Well, sometimes, but not always. As proved the case with my buddy Mike’s bike last weekend. I think there are some good lessons for finding noises here, which I’ve put in bold.

Mike’s rattling Cervelo

Mike is on our masters racing team and I admire him a lot because he’s fully committed himself to taking up road racing. Only a year ago, he was tootling around on an ancient Fuji several sizes too small for him and hardly knew what a paceline was.

Now he’s on a new Cervelo aero road rig, racing throughout the season. And he’s about my age, so we race in the same group as teammates.

All of this, and the fact that he’d do anything to help anyone, makes me want to help him. So, when he emailed and said his bike was making a loud rattling when he was in his 34-tooth chainring and 2 largest cassette cogs, I told him to check for rubbing on his front derailleur cage, thinking he might not have adjusted the inner limit screw correctly, since he recently went to easier gearing.

Mike wrote back that the chain definitely wasn’t rubbing and said he’d demonstrate the problem on our Saturday training ride the next morning.

Wow, what a racket!

Getting someone else to hear a noise is one of the best ways to find and fix them, because they might hear it better than you can and/or have a new idea on where it might be coming from. Like the car that won’t act up for your mechanic, though, a lot of times, a noise that’s driving you crazy isn’t easy to create so that other people can hear it.

But, all Mike had to do is pick up the rear end of this bike, spin the crankset around a few times, and rattle, rattle, rattle – the noise was as loud as can be. Everyone was eager to get going on our ride so I couldn’t look very closely, but it was clear the noise was not coming from a rubbing front derailleur.

As we rolled out, Mike rode alongside and we could all hear his bike rattling away, like there was something loose and vibrating inside his carbon frame. It didn’t seem dangerous in any way, so we decided we’d try to figure it out after the ride. But, clearly, Mike was annoyed having to put up with it, as were the riders listening to it, making the usual funny comments.

Upon closer inspection

Mike came over to my house later and we put the bike in the repair stand. Sometimes a bike won’t make a noise unless you’re riding it. But his Cervelo was only too happy to sound off in the stand.

With two of us looking as I pedaled by hand, we determined that nothing obvious was rubbing. The rattle only occurred during pedaling and only at a certain pedaling speed, too. We both noticed that the noise was loudest at the base of the seatpost and inside the frame.

Noises often travel and make you think they’re coming from someplace else. That can add to the wild goose chase. But, to rule it out, you might as well investigate.

Mike’s rear brake is held onto the carbon frame with an unusual bolt-on metal plate rather than the standard 5mm recessed allen nut. Since that plate was located close to the rattle, it seemed like there might be a loose brake bolt or part causing the noise. We removed the brake entirely but the blasted noise persisted.

Parts swap

Another helpful technique you can do if you’re working with a friend who has a bike with parts that work, is change out components to use the process of elimination to figure out what’s causing the noise.

For Mike’s bike, we decided to try putting my rear wheel into his frame. So I swapped out one of my rear wheels with a 10-speed cassette with 28-tooth largest cog to match Mike’s setup. But Mike’s SRAM Rival kit has a SRAM chain and cassette, while my setup is all Shimano. I also have a standard 53/39 versus his compact 50/34 crankset.

While my wheel was significantly quieter in Mike’s bike than his, we could still get his bike to rattle. Argh.

Mike figures it out!

With Mike’s wheel back in place and the rattle as loud as ever, Mike wondered out loud if his new longer-cage rear derailleur might be the problem. He explained that he’d had it put on by the shop when he went to lower gearing and found his previous derailleur didn’t allow him to run a long enough chain for the bigger cog.

Nothing was rubbing, so it didn’t seem like the derailleur could be at fault. With that in mind, I suggested that maybe it was the chain. I’ve seen and had bad chains on occasion, and Mike also said his chain was brand new, so maybe….

We thought about that as I pedaled at just the right speed and his Cervelo made the awful noise, like an old rattletrap instead of the svelte speed machine it is.

Mike then reached over, put his finger on the derailleur cage behind the lower pulley and pushed it forward. This changed the relationship of the pulley to the chain so that less than half the pulley teeth contacted the chain, and the noise stopped cold. Mike and I looked at each other amazed, and commenced dancing around my garage, high-fiving.

The fix

To explain a bit more, earlier this year I had checked the alignment of Mike’s derailleur hanger so I was sure his frame was fine. And, his derailleur was brand new. So I had assumed there couldn’t be anything wrong with that pulley. It just goes to show that with crazy noises/problems like this, you can’t assume anything and have to check.

Carefully looking at that lower derailleur pulley from various angles, Mike and I could see that it was clearly canted to one side, causing the chain to ride off the teeth. There were no signs of any damage, so it must have come that way from the factory.

No wonder it was so hard to find what was causing Mike’s rattle! This simple glitch back at the pulley caused the obnoxious noise because it traveled through the frame and was amplified by the hollow carbon frame that acted just like the speakers in your stereo.

All it took to fix it was bending the derailleur cage sideways until the pulley was aligned so that each tooth met the chain perfectly.

Ahhh, silence at last. And it only took two cyclists and about a day to find it! To help save others from a similar fate, please be sure to share your crazy noise story in the Comments below.

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Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s streak of consecutive cycling days has reached more than 8,000. Click to read Jim’s full bio.