The skate helmet certification requires multiple impacts, while the bike certification does not. But, some bike certified helmets claim to be multiple impact...
1. MULTIPLE IMPACT SKATE HELMETS (THE ASTM STANDARD)
The ASTM F1492 skateboard helmet standard requires skate helmets be capable of absorbing multiple impacts. The softer foam liner inside these helmets absorbs impacts and immediately rebounds to it's original shape. So, skate helmets that meet the ASTM skateboard helmet standard are designed to be multiple impact helmets. However, this does not mean ASTM F1492 helmets are approved for bicycle use! To be approved (and legal) for bicycle use, the helmet must also meet the CPSC bicycle standard.
2. SINGLE IMPACT BIKE HELMETS (THE CPSC STANDARD)
The CPSC bicycle helmet standard requires helmets to protect the rider from a single impact. In a typical bike helmet, the hard foam liner inside the helmet crushes as it absorbs the force of the impact. This is by design, so the foam absorbs the impact instead of your head! But, since the foam crushes at the point of impact, the helmet will no longer offer the same amount of protection in that area. How much protection is lost? It depends on how fast you were going, what you hit, the condition of your helmet, etc. etc. Helmet manufacturers recommend (naturally) that you replace your bike helmet after any significant impact. What is significant? Can't say for sure. For certain, if the shell is cracked or you can see that the foam is crushed - replace the helmet. But, not all damage is visible. So, ultimately, it's your call.
3. MULTIPLE IMPACT BIKE AND SNOW HELMETS
Does a multiple impact helmet for bicycling and skiing exist? The bicycle helmet would need to meet the US CPSC safety standard. Here's what our suppliers say:
- ProTec, in past years, offered their SXP line of multiple-impact helmets. According to ProTec, due to "advanced chemical structure and sophisticated processes used to create SXP liners", their SXP helmets rebound to their original shapes to maintain their impact qualities.
- Bell and Giro - historically - did not claim their helmets to be multiple impact helmets. Prior to introducing the "patent-pending, impact-absorbing dual density Vinyl Nitrile (VN) liner" Bell/Giro argued that helmets, regardless of the liner material used, couldn't be assured to offer unlimited multiple-impact protection. There is no way to predict how hard - and where - you might hit your head the next time you fall. As a result, Bell and Giro both recommend replacing your helmet after a "serious impact." (NOTE: with the new Giro VN liner, they have changed the decision criteria and conversation about multiple impact capability)
- What's our take? Both sides of the argument have merit. It comes down to this: what are you comfortable with? One guideline may be this: if the impact was hard enough to make you say "wow, that was a hard hit", then think about replacing your helmet.
Not sure whether you need to replace your helmet? Check out our articles: