Bottom bracket assembly

So my bike makes this noise.

To me, it sounds like a buzzing bee, or the rapid-fire vibration of a rattling ball bearing.

Much to my chagrin, I can’t quite figure out why it happens or when it will happen — it comes and goes randomly and without warning. Equally irritating, I can’t seem to locate the source of the noise. Sometimes the dreaded sound appears to come from the bottom bracket/crank area, and in other instances, more from the front fork.

This much I do know: When it gets going, that noise drives me crazy.

I know I am not alone out there, riding my noisy bike. In a couple of my triathlon races, I have heard emissions and other mysterious racket vociferous enough to make one wonder if the bike they belong to might fall apart at any moment. During one race a few months ago, when a teenage boy was passing me, his bike was so loud that I could not hear what he was saying during a few brief moments of friendly chatter.

So what do you do if you have a bike that will not shut up?

“I would probably get it checked out,” says Joel Husmann, a bike technician at Pine Mountain Sports in Bend. “A bicycle is a mechanical machine, so there’s going to be a certain amount of noise just involved with the workings of a bike. But most people have a pretty good sense of what’s an acceptable noise for a working machine and what is off that normal scale.”

In most cases, says Don Leet, co-owner of the Sunnyside Sports bicycle shop in Bend, the sound probably is not cause for worry.

“I would say 90 percent of the time, creaks are not dangerous. They’re just obnoxious,” says Don Leet, co-owner of the Sunnyside Sports bicycle shop in Bend. “But you should get them checked out just to make sure your frame is OK.”

In Leet’s estimation, the most common bike creak cause is a loose wheel. Making sure the wheel is in the proper position and tightening the quick release could be all that is needed to correct the noise.

Husmann, who says customers come to the shop “all the time” complaining of bike noises, notes that brakes are another common culprit. If your brakes are squealing, it could be due to a contaminant in the brake pads or on the rotor, in the case of mountain bikes with disc brakes. Also, the pads may be worn down.

Sometimes, Leet points out, brake pads even pick up some of the metal on the wheel rims.

“Then it sounds like you have sandpaper rubbing onto your rims,” Leet explains. “And instead of that smooth rubber-to-metal feeling, you actually have this kind of grating, weird, louder noise, and you think there’s something really wrong with your bike.”

Leet — though he was not willing to oblige me with any imitations of bicycle noises — did list a number of other noise sources: derailleur hangers, loose chain rings and pedals, and even loose or missing bolts in locations such as the seat stay.

In many cases, all that is needed to fix the problem is some lubrication (such as to a chain) or a new part (such as that absent bolt). Or the solution may be a simple adjustment, such as to brake calipers that have been knocked askew — causing brake pads to rub against rims — and can be moved manually back into place.

“It’s not that you shouldn’t worry, it’s just that most creaks are pretty benign,” Leet says. “They’re just loud.”

Of course, the problem could be a serious one, such as a crack in the bicycle frame. In that case, the irritating noise is the least of your problems, as the bike frame could fail.

To diagnose a creak, squeak, clank or crunch, bike technicians work their way through the possibilities until they find the source. Husmann says the technicians at Pine Mountain may ask for information from the bike owners, which can help narrow down the possibilities, but the owners do not always know the cause. Sunnyside technicians, Leet says, will test-ride bikes each time they make an adjustment to confirm or eliminate a potential trouble source.

The solution may be quickly discovered, but sometimes noises do not yield their secrets easily — sounds Husmann calls “mystery creaks” because the technicians struggle to reproduce them. Noises can be tricky because the source of the sound and the location may not be one and the same. Or because they come and go, like mine.

“If it only happens once in awhile, that’s the hardest thing for us to fix,” Leet explains.

Leet recalls one customer who purchased from Sunnyside a Trek bicycle that would start creaking after about a dozen miles of hard riding. But the source could not be discovered, and the customer received a new frame from Trek.

That is not a likely resolution. Instead, chances are that your trusty bike technician will be able to find the source of your frustrations and fix it. And if it does turn out to be a more serious safety issue, at least you are not wheeling around at a high rate of speed on a dangerous machine.

Those are both better alternatives than putting up with the noise indefinitely while riding. You should not have to lose your mind to ride your bike. Like I am.

I should do something about that.

Problem areas on bikes

When trying to figure out where a strange noise is coming from on your bicycle, these are some common places to check:

•Brake assembly

•Bottom bracket assembly

•Cassette lockring

•Quick release assembly