How old a used helmet really is, and what to do when the date is gone

A used helmet almost always looks newer than it is. The shell gets polished, the visor gets replaced, the padding gets washed. What cannot be polished is the age of the materials.

Why about five years

The figure used here, roughly five years from the production date, is not a law. It is the common recommendation from helmet manufacturers and safety bodies, and the reason for it is in the materials.

The layer that actually absorbs an impact is not the outer shell but the EPS inside it: a hard foam that works by crushing in a controlled way when a head hits something. That material ages whether or not the helmet is ever worn. Sweat, sunlight, the heat of a bike's top box, and time on its own make it stiffer, and foam that has hardened absorbs less and passes more of the blow through.

Which means a helmet that is "still spotless, hardly used" can be the worst example of all: spotless because it was stored, and ageing the whole time it was stored.

The production date is inside, not on the box

If the helmet still carries one, the production date is usually in one of three places: printed on a label under the cheek pad, printed on the chin strap, or moulded into the inside of the shell near the neck. The format may be a month and year, or a four-digit code.

The important part: it is the date it was made, not the date it was bought. A helmet can sit in a distributor's warehouse for a year before it sells, and the count still starts at manufacture.

When the date is no longer legible

This is the common case. The label has years of sweat on it, or a previous owner pulled it out, or it was printed somewhere that has worn away.

The production date used to be required when listing a helmet here. That was the right idea with the wrong question: half of used shells have no legible date left, and requiring one produced exactly two things, honest sellers who could not finish a listing and other sellers who invented a number.

The question is now one the seller always knows: how long they have owned the thing. It does not replace the age of the shell and does not pretend to. A shell made in 2015 is out of date whether its owner has had it a week or a decade. But "owned since March 2024" is a fact somebody can stand behind, and an invented production date is not.

When a listing shows both, both are true and both are useful. When it shows only one, that is not the seller being careless.

Estimating the age without a date

There is no certain method, but there are several that are good enough:

• The model and when it was on sale. Most helmets belong to a generation you can look up. If that model stopped being made six years ago, not one unit of it is still within its service life.
• The state of the cheek pads. Foam that has gone flat and does not spring back points to long use rather than long storage.
• Strap and stitching. Webbing shows its age more plainly than a shell does.
• The visor and its seals. Rubber that has hardened and finely cracked is an honest marker, because nobody bothers replacing it for a photograph.

What the listing page does

A helmet's age is shown as an age, not as an expiry date you have to count backwards from, and it appears only on helmets that actually carry a date. The row does not appear with an empty dash when the data is missing, because a blank field reads as an incomplete listing when what really happened is that the question was never asked.

The SNI status is stated on every helmet, and that has a piece of its own: what is guaranteed and what is not.

The rest is between you and the seller, in the order chat, before the money moves.