Oh, and in case no one ever told you, no bike helmet is meant to last for ever.
Of course, knowing when to replace your brain bucket isn't always obvious, which is why researchers at Germany's Fraunhofer Institute are developing a bike helmet that starts stinking to high heaven when it's damaged.
Fraunhofer has developed a manufacturing process that injects microcapsules containing odoriferous oils in the helmet's protective polymer.
The plastics produced by the process start to smell if they develop small cracks. Large cracks really cause a stink, the company says.
"Cyclists often replace their helmets unnecessarily after dropping them on the ground, because they cannot tell whether they are damaged or not," explained research scientist Christof Koplin in a statement. "The capsules eliminate this problem. If cracks form, smelly substances are released."
The capsules are added to a polypropylene that is injection-molded to form the final shell fastened to the head gear, Koplin said.
According to Fraunhofer, "a layer of melamine formaldehyde resin encloses the capsules so that they are completely airtight and mechanically sealed. It also protects the tiny pods, which are subjected to temperatures of 200 to 300 degrees during injection molding as well as static pressures of up to 100 bar."
The company has yet to decide on "smell characterizations."
In other words, they're still perfecting the stink.