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How long is a tree year?
Last Post 05/28/2022 12:56 PM by Dale Dale. 5 Replies.
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05/26/2022 12:57 PM
I ask because I just got a POC Tectal to replace the Trebec I've had since '14.  Nice helmet!  Mounted the mirror, then started reading the instructions.  Of interest - when do I replace it.  Well, and I quote "It is recommended to replace the helmet every tree years at least."

If a tree year is like a dog year, this could get expensive.  The Doug Firs in my front yard are probably good for 2-300 years.  So 90 years ( human life expectancy) / 300 = 0.3 "tree" years or a little under 4 months.

And a little more serious - the Trabec I am replacing is the best helmet I've had by far.  It has held up very well.  I have not repaired or replaced anything, even pads.  I do use a skull cap always as I have for the past several helmets.  Leave the house wearing a clean one.  I haven't tested either it's impact behavior or the MIPS, but comfort-wise it simply disappears.  And that is despite the considerably more coverage and weight than any recent helmet I've worn.  (My old Bell Biker was probably the Trabec's weight or more.)  Trabec - 357g.  This Tectal is 37g heavier with the mirror mounted so I'm guessing 10-30g lighter.

So here's hoping this new one is just as comfortable and it has a life just as boring.
Orange Crush


05/26/2022 01:59 PM
300 sounds about right for Douglas Firs but it varies massively by tree type and region.

For context, Douglas Firs reach their "teenage years" after about 40-50 years. This is when their growth and water use rates are highest. Well documented. I quoted some studies from OR on the matter recently for some work we did on factors affecting declining summertime streamflows.


05/26/2022 08:07 PM
Helmet manufacturers (who of course want to sell more helmets) report that the EPS loses its goodness over time, and therefore they opine with remarkable specificity that we should buy a new helmet every X years. Moto helmet makers make the same claim. No doubt there is some truth that EPS degrades, especially in heat (hot car) and maybe if exposed to ozone (electric motors) or other agents. The actual degradation is unknown to me, and X may be arbitrary.

As for dating helmets in tree years, east coast trees can last a century or more, but tree years here likely are shorter than in Ben's environs.


05/27/2022 09:03 PM
If they are French Canadians, maybe they dropped the extraneous "h", but three years seems a bit too often.


05/27/2022 10:41 PM
Posted By smokey 52 on 05/27/2022 09:03 PM
If they are French Canadians, maybe they dropped the extraneous "h", but three years seems a bit too often.

POC are Swedes.  Don't know what they do with "h"s.  My first has gone 7 1/2 years so the tree year of a 675 year old tree.


05/28/2022 12:56 PM
Most moto racing regs stipulate the helmet must be less than five years old from date of manufacture.

One of the dealers I called on back in the day had a three year old inexpensive helmet that he'd taken to a bandsaw to expose the EPS. It was hard as a rock, absolutely no give when you pressed a thumb into it. I routinely throw helmets out at about four years.
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