It is said that there have been many bikers who have become loners because of their cracking. Because what is already annoying on rides alone can really wear down the team spirit on long tours. The problem is that the cause of the clicking is often difficult to find. It takes a lot of calm, the right tools and, of course, the right expertise. What exactly leads to success when "cracking" and "creaking", can now be read in BIKE 2/2021.
But which mountain bike components can crack? And which are the most common problem areas? We provide a brief overview here in advance. In the interview below with Marco Brust, Managing Director of the accredited bike testing laboratory Velotech.de, you can read how professional mechanics go about eliminating even the slightest cracking noises, why even new bikes can make annoying noises and why carbon in particular can be a problem.
Cracking on the bike: Notorious problem areas
Theoretically, cracking and creaking can occur anywhere on the bike where several components twist or rub against each other. So actually everywhere. Nevertheless, there are a few places where the noises occur particularly frequently. Here is an overview:
Drive and pedals: Anyone thinking of cracking will quickly suspect the drivetrain as the cause. The bottom bracket can of course crack, but it can also be the chainrings that are not screwed tight enough to the crank. However, the most common and often overlooked cause is the pedals! No wonder. Because with cleats, click mechanism, axle and bolting in the crank, there are a lot of problem areas in one place.
Saddle and seat post: As the saddle and seat post are constantly under attack from dirt, annoying noises are not uncommon here either. In particular, if cracking occurs when pedalling while seated, the weight shift on the saddle may be the cause. The cracking noise can often be provoked by specifically loading and unloading the saddle.
Rear end: The rear triangle of MTB full-suspension bikes often cracks. No wonder, because the many joints are difficult to protect from wear in the long term and sooner or later the sand eats into them.
Marco Brust in an interview: "Even new bikes can crack."
Cracking is not just a nuisance for private individuals. Large bike companies and even courts often come into contact with the issue. Then professional testing companies such as velotech.de comes into play. The accredited test laboratory specialises in muscle-powered vehicles, including bicycles, and also prepares expert reports on the subject of noise development on bikes.
BIKE: Mr Brust, your company actually specialises in expert opinions on product safety. Are cracking and creaking bikes a big issue for you?
Marco Brust: Of course. Cracking and creaking are among the most common problems that we receive in the laboratory. And cracking can also have to do with safety, for example if it indicates defects or overloaded components.
For whom do you prepare expertises on the subject of cracking?
Our customers are very diverse. Our customers often come from the industry. Because even new bikes can crack. And then, of course, the manufacturer endeavours to find a solution before the product is launched on the market. But we are also sometimes called in as experts in court proceedings. And private individuals also ask us to provide expert opinions if they can't figure out the problem themselves. We simply have completely different ways of getting to the bottom of such problems.
How do you imagine it works in the lab? Searching for the sounds?
Thanks to the various test benches we have here in our laboratory, we can simulate very specific loads without the bike itself moving. Cradle pedalling, loads on the rear triangle and steering head bearings and much more. This gives us the opportunity to listen very closely to the individual areas under load using a stethoscope. It may sound a bit crazy at first, but it's a guaranteed way to find the cause of the crackling!
Why do many hobby mechanics find it so difficult to find the crack?
I think one of the reasons for this is that modern frames make it particularly difficult. We are seeing more and more voluminous down tubes, especially on e-bikes with integrated batteries or carbon frames. They act like the sound box of an instrument and amplify the cracking that would otherwise be barely audible. The thinner the material, the more pronounced the effect. This is why carbon is so susceptible. And because the sound is amplified in this way, its actual source can often hardly be recognised with the naked ear.
Do you have any tips for bikers?
If you have problems with cracking, you can deliberately drop the bike onto the front and rear wheel from a height of around 30 centimetres. A test ride will take you even further. Test the following loads: pedalling with a heavy load, sliding back and forth on the saddle and braking hard on the front wheel and rear wheel separately. This allows you to reproduce many noises that occur under normal load and then narrow them down further.
Adrian Kaether
Editor
