Helmet Lifetime - Really?

[Claud]

I was a bit surprised yesterday that the local Bikeability trainer told my son's class that they needed to check the 'date of manufacture' on their helments, and "should" get new ones if they're more than 3 years old - got me going on a good old rant to my son, that did! Is this really necessary, or have the trainers been duped by helment manufacturers who just want to increase their profits by getting people to dump a piece of kit that's pretty much as good as it was when new? Is there some genuinely independent info on this somewhere?

[hubgearfreak]

Is there some genuinely independent info on this somewhere?

yes, i think that there's some quite thorough research about the effectiveness of helmets.
i don't think that old ones are less effective than new though

[stewartpratt]

Polystyrene degrades in an outdoor environment, mainly through UV exposure, does it not? Plus there's also the potential cumulative effect of knocks over time which can also reduce the capacity to absorb energy.

Three years is going to be an "on the safe side" figure, but I think the principle has foundation.

[Vorpal]

The plastic outer shell deteriorates more quickly than the polystyrene. UV will make it more brittle with time. If the wearer is not a frequent cyclist and has stored the helmet out of direct sunlight, it is reasonable to assume a longer life than 3 years. Additionally, older helmets (more than 10 years old) have designs that perform better in laboratory tests. Although the plastic may have become more brittle, the protection may still be comparable to a new helmet (if it's been looked after, not dropped or bumped, etc.)

However, children are rougher on helmets, and less likely to ensure that they aren't dropped or bumped. If you believe that your son needs a helmet, it's probably a good idea to replace it at least every 3 years.

cyclehelmets.org used to have some information about replacing helmets, but I can't find it on their site.

[xpc316e]

I saw a woman yesterday in Cambridge who had a helmet that was obviously bought when God was a boy. Nearly all of the outer plastic shell was missing and as I understand it, this serves to distribute forces over a larger area should the helmet be impacted. This particular helmet needed to be replaced, but sadly any new one would probably be worn as this one was - on the back of the head and with straps so loose as to render it useless. This kind of report needs to be more widely brought to notice.

[Steve Kish]

FWIW, my 1991 Spesh Sub Zero is still in active service but if I ever have a wallop in one, it's a one way trip to Dustbin City for it!

[NUKe]

. Nearly all of the outer plastic shell was missing and as I understand it, this serves to distribute forces over a larger area should the helmet be impacted.

The plastic on cycle helmet is little more than decorative. The forces dispersion idea comes from Motorcycle helmets, where the shell is much harder and designed to disperse forces. As does the 3 year rules which comes from ACU racing rules of the 90's. They may be even stricter now.