Myths of the Bike Industry: Helmets wearing out.

Allow me to implicate myself in a scam that I've been unwittingly perpetrating for almost a decade, and that is, the myth that over a period of time helmet foam, like a bologna sandwich, goes bad.

The line I was taught to say ahttp://www.bellhelmets.com/product-faq, http://www.xsportsprotective.com/pages/when-to-replace-your-bicycle-helmet, http://bikefat.com/is-it-time-to-replace-your-bike-helmet/).

Lookin' fly, player.

s a retailer is that a bike helmet should be replaced every 3-5 years. This timeline is backed up by many manufacturers as well as subsidiary blogs and info sites (

The reality, however, is that time does not play a part in the lifespan of styrofoam. Solvents hurt foam, blunt and sharp trauma hurts foam, as do burrowing animals, but time alone plays no part in the lifespan of a helmet. Helmet manufacturers know this, but it's in the best interest of their bottom line not to be totally honest with their consumers.

From Helmets.org, here is part of a press release by MEA Forensic, the company who ran tests disproving the notion that helmets age out:

MEA and collaborator Collision Analysis collected 1,500 used helmets from consumers and eliminated any that showed damage or did not have date of manufacture stickers. The helmets studied had dates that ranged from 1987 to 2013. They crash tested them at 3 m/s (a drop of 1.5 ft.) and 6.2 m/s (a drop of 2 meters--the CPSC standard drop) on a flat anvil in the dry ambient condition. There were only four that exceeded the 300g maximum threshold: three of the oldest models made to meet only the old ANSI standard, and one newer model that had been recalled. So 671 of the helmets passed the current CPSC impact performance standard. 

MEA's analysis showed that there was no significant impact performance change with age. Their 26 year data including all 675 helmets tested produced only a 0.7g per year increase in impact readings at the higher drop height. On average, road helmet models produced results 40g lower than skate-style models, and extra-small helmets were 21g lower than large helmets. Lower g's registered in the headform means less shock passed through to the head, but since they are averages they may not apply for a particular helmet model. 

After crash testing the helmets on a standard test rig, MEA took core samples from an uncrashed area of 63 of the helmets and tested them at the equivalent of a 6.2 m/s helmet impact. This generated data based solely on the foam performance. They collected stress and strain data related to aging of the foam. Again, the findings indicate that helmet liner foam does not deteriorate with age. 

For more, you can check out MEA's website, http://www.meaforensic.com/helmet-testing-research.

Now there are lots of good reasons to replace your helmet, and the bicycle helmet safety institute can spell them out better that I can here, but next time your shop tells you that your helmet's too old, you can tell them their info's too rotten.