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In conversation with my housemate last night he said that if a cycle helmet is dropped, even from a height of a meter or so, onto a hard surface then it needs to be replaced. He said the internal structure of the helmet could be damaged, even if there is no visible dent. I've done a but can only find others asking the same question, with unsatisfactory and variable answers.

If I drop my cycle helmet onto a hard surface, from a height of a meter or so, under what circumstances do I need to replace it?

Goodbye Stack Exchange
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fredley
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    Possibly duplicate? http://bicycles.stackexchange.com/questions/592/when-or-how-often-should-i-replace-my-bike-helmet – Oddthinking Feb 20 '12 at 11:07
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    everything "could be". It "could" have been dropped during manufacture, during transport, in the store, etc. etc. and you'd never know. – jwenting Feb 20 '12 at 11:25
  • I thought this true for motorcycle helmets, but I just read [this](http://www.smf.org/helmetfaq#aDroppedHelmet) from Snell who are responsible for one of the safety standards. The basically say the the helmet is _probably_ ok. Given a bicycle helmet is much lighter, I would think it is unlikely to damaged by a simple drop. – dave Feb 20 '12 at 12:09
  • YES! Absolutely! It could have a defect that’s invisible, and if you fall on that same part of the helmet again, you won’t have the protection that you should. And even if your helmet never takes a hit, it’s a good idea to replace it at least every five years (or sooner if you ride often), –  Feb 20 '12 at 19:18
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    @Karisa - Unless you expose the helmet to *extremely* inclement weather when riding (or you hit a lot of tree branches), how often you ride shouldn't make much difference. Ideally, when you ride, the helmet just sits on your head and isn't actually put to its intended "use". – Goodbye Stack Exchange Apr 09 '12 at 01:50

1 Answers1

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This is somewhat dependent on manufacturer and the quality of the helmet sold, which can vary a lot.

For the USA, there is the Bicycle Helmet Safety Institute which does various tests and gives information.

For bike helmets to be legal in the US, they are required to pass a test of being dropped between one and two meters on an anvil.

All of the standards discussed here require the helmet to pass a lab test where it is placed on an instrumented headform, turned upside down and dropped for a measured distance onto an anvil. The anvil can be flat, round (hemispheric) or another shape like a curbstone, a skate blade or a horse's hoof. Drop distances vary but are generally between one and two meters (3.3 to 6.6 feet).

Their guidelines about when to replace a helmet mention say little about a short drop on a floor.

You can also crack the helmet foam or damage it by dropping the helmet on a hard surface. The cracks may be small and hard to see, so you need to look carefully. Cracks in the foam always require replacement of the helmet.

So, look for visible cracks very carefully.

In general:

Did you crash it? Replace!

Did you drop it hard enough to crack the foam? Replace.

Is it from the 1970's? Replace.

Is the outside just foam or cloth instead of plastic? Replace.

Does it lack a CPSC, ASTM or Snell sticker? Replace.

Can you not adjust it to fit correctly? Replace!!

Do you hate it? Replace.

I wouldn't think that a short drop would have enough force to render the helmet ineffective as a protection device. Going by the BHSI guidelines, unless there is visible damage or it was dropped from a great height, the helmet should not need to be replaced.

Oddthinking
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