Large Helmets

For all discussions about this "lively" subject. All topics that are substantially about helmet usage will be moved here.
Steady rider
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Re: Large Helmets

Post by Steady rider »

The topic is 'large helmets' there is some data, (yes wondering maybe), it provided peak rotational acceleration (PRA for ease of discussion) from impacts at 8.5m/s,and used 3 head sizes, A, E and J, roughly A = 50 cm, E = 54 cm and J = 57cm. Larger sizes M = 60cm and O = 62 cm were not included in the table, the table only provided for PRA on E and J. For E size the average value was 5334 rads/sec/sec and for J size 13506 rads/sec/sec. Table 4.9 https://trid.trb.org/view/810710

It suggests larger helmets incur higher levels of rotational acceleration compared to medium sized helmets. It could be an issue worth further investigation. I would be concerned at wearing any large helmet.

ps
Assuming that the response of the unhelmeted head is similar to the helmeted head during an oblique impact at 8.5m/s at 15º, this may generate between 7500rad/s² and 12000rad/s² of rotational acceleration. This is potentially more severe than the 3000rad/s² to 8500rad/s² measured during abrasive and projection oblique tests with size 54cm (E) helmeted headforms. However, for the most severe cases using a size 57cm (J) headform, rotational acceleration was typically greater than 10,000rad/s² and increased to levels of 20,000rad/s², a level at which a 35% - 50% risk of serious AIS3+ injuries is anticipated.
Unhelmeted 7.5 to 12k, J size 10 to 20k, who knows what M or O size would result in.
tim-b
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Re: Large Helmets

Post by tim-b »

The topic is 'large helmets'
The first post is quite clear, "A member of my family who shall remain nameless has a head that is too big for any of the helmets we have tried so far. Can anyone recommend helmet brands that fit "larger" heads please"
If you want to research your suggestion that larger helmets incur higher levels of rotational acceleration compared to medium sized helmets then please go and do it and start your own, related, thread
Thanks
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Steady rider
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Re: Large Helmets

Post by Steady rider »

A member of my family who shall remain nameless has a head that is too big for any of the helmets we have tried so far. Can anyone recommend helmet brands that fit "larger" heads please.
The details I have quoted shows larger helmets may pose a serious risk and should be considered. I do not intend to start a separate thread, as at present there would be little to add.
Jdsk
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Re: Large Helmets

Post by Jdsk »

You've been asked politely not to divert this thread from its useful purpose.

You've raised this paper many times in other threads, and it has been discussed in those.

Jonathan
Steady rider
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Re: Large Helmets

Post by Steady rider »

Can anyone recommend helmet brands that fit "larger" heads please.
I am not preventing anyone from recommending brands but if the larger sized helmets pose an added risk, should they be recommended without any warning?

The person buying the larger size, may wish to ask British Standards or Cycling UK about the risks or buy the smallest available that will still fit. Is there a list of helmets with available helmet sizes?
drossall
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Re: Large Helmets

Post by drossall »

Please stop this. For those of us needing larger helmets to take part in events, there is generally a choice of one make, if we are lucky. Can we get the thread back on track? Please?
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pjclinch
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Re: Large Helmets

Post by pjclinch »

Steady rider wrote: 7 Aug 2022, 9:37pm
Can anyone recommend helmet brands that fit "larger" heads please.
I am not preventing anyone from recommending brands but if the larger sized helmets pose an added risk, should they be recommended without any warning?

The person buying the larger size, may wish to ask British Standards or Cycling UK about the risks or buy the smallest available that will still fit. Is there a list of helmets with available helmet sizes?
It's about shape as well as size. What is generally accepted is that for a helmet to work properly (i.e. according to its design spec) it has to fit properly, so you pretty much sort out what you need to sort out by trying them on. "Fit properly" precludes needlessly over-sized.

Should narrower tyres be sold with warnings that they can provide less grip?
Should luggage be sold with warnings that it can affect balance and handling?
Should clipless pedals be sold with warnings that they can cause enormous embarrassment at traffic lights when you botch unclipping?

Pete.
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Nigel
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Re: Large Helmets

Post by Nigel »

drossall wrote: 7 Aug 2022, 10:32pm Please stop this. For those of us needing larger helmets to take part in events, there is generally a choice of one make, if we are lucky. Can we get the thread back on track? Please?
For lower-level events (club TT's and the like), does anyone actually inspect things, or is it just "wearing helmet, off you go" ? Because I wonder if the solution for the purposes of box-ticking is to modify something so it does fit, either carving out material to create space, or a "cut&shut" to enlarge ? Of course such changes remove any possible protection, but if its "box ticking", then box ticked.
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pjclinch
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Re: Large Helmets

Post by pjclinch »

Nigel wrote: 8 Aug 2022, 9:02am
For lower-level events (club TT's and the like), does anyone actually inspect things, or is it just "wearing helmet, off you go" ? Because I wonder if the solution for the purposes of box-ticking is to modify something so it does fit, either carving out material to create space, or a "cut&shut" to enlarge ? Of course such changes remove any possible protection, but if its "box ticking", then box ticked.
The Box That Is Ticked is almost always that it is certified to some recognised standard (typically EN1078), because that's easy to write down and relatively easy to work with.
As soon as you alter a lid from what is sold you no longer have what was tested to the standard, so there goes your ticked box.

Perhaps of note is that if you e.g. stick a Go-Pro on then it's no longer what was tested so really shouldn't be allowed under that proviso, but the reality is that you'll find wide variation in the degree of worrying about compliance. I've seen tick boxes for "correctly fitted helmets" in my time for things where folk have had the traditional falling off the back of their head and straps so loose that you could easily get a whole arm between the strap and the head.

Pete.
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Steady rider
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Re: Large Helmets

Post by Steady rider »

https://pezcyclingnews.com/features/a-c ... -tt-bikes/
a bit off topic but shows all aspects need consideration.
Nigel
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Re: Large Helmets

Post by Nigel »

pjclinch wrote: 8 Aug 2022, 11:15am
Nigel wrote: 8 Aug 2022, 9:02am
For lower-level events (club TT's and the like), does anyone actually inspect things, or is it just "wearing helmet, off you go" ? Because I wonder if the solution for the purposes of box-ticking is to modify something so it does fit, either carving out material to create space, or a "cut&shut" to enlarge ? Of course such changes remove any possible protection, but if its "box ticking", then box ticked.
The Box That Is Ticked is almost always that it is certified to some recognised standard (typically EN1078), because that's easy to write down and relatively easy to work with.
As soon as you alter a lid from what is sold you no longer have what was tested to the standard, so there goes your ticked box.
I understand that. But, do those who tick the form at the start of a club TT understand it, or even care (eg. "more effing paperwork from HQ..".) ? If they just go "helmet - tick" then the rider is in the event.
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pjclinch
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Re: Large Helmets

Post by pjclinch »

Nigel wrote: 8 Aug 2022, 1:40pm
pjclinch wrote: 8 Aug 2022, 11:15am
Nigel wrote: 8 Aug 2022, 9:02am
For lower-level events (club TT's and the like), does anyone actually inspect things, or is it just "wearing helmet, off you go" ? Because I wonder if the solution for the purposes of box-ticking is to modify something so it does fit, either carving out material to create space, or a "cut&shut" to enlarge ? Of course such changes remove any possible protection, but if its "box ticking", then box ticked.
The Box That Is Ticked is almost always that it is certified to some recognised standard (typically EN1078), because that's easy to write down and relatively easy to work with.
As soon as you alter a lid from what is sold you no longer have what was tested to the standard, so there goes your ticked box.
I understand that. But, do those who tick the form at the start of a club TT understand it, or even care (eg. "more effing paperwork from HQ..".) ? If they just go "helmet - tick" then the rider is in the event.
"Implementation Dependent"
In other words it will vary.

While there is a huge amount of worrying done around helmets for formal riding settings there is practically zero hard information available in courses I've attended for sports coaching and learn-to-ride instruction about them beyond "this is how they should be fitted". I've had courses taught by folk with hilariously badly fitted helmets, so not only is there no guarantee that an event will have consistent and/or relevant checks, but as far as I can tell there's no real guarantee that people doing the background instruction will have a consistent basis to their teaching.
Part of this is a side effect of helmets being a touchy subject. Official organisations (certainly including British Cycling, for whom I'm a L2 coach) strike me as very reluctant to talk about helmets (when you look at typical helmet flame wars this is kind of understandable, but when you look at their responsibilities to cyclists it's also rather pathetic). So they come up with rules and boxes to tick and sort of assume everyone will be magically clued up enough to implement them by just knowing the right stuff through some sort of information osmosis.

And just like Marianne Vos may tell you, this "well, it's really down to which side of bed the official gets out of" attitude does go right to the very top!

Pete.
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drossall
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Re: Large Helmets

Post by drossall »

Helmets are not checked at our club 10s, nor were they when I did RideLondon. For a start, they didn't notice that it was a 20-year-old model that, at the time, was the only one I had ever found to fit - I then damaged it on the train on the way home :-(

What I will say is that the local officials at my club 10 are my friends, and I won't put them in a difficult position. That said, I can't see the fact that I've carved out a helmet to fit being something that gets them into trouble. It wouldn't occur to CTT to impose such checks because, as far as I know, and with one or two individual exceptions with whom I have communicated, they are blissfully unaware that anyone might need to modify a helmet.

But we're drifting again from the basic point of identifying models that fit larger heads.
Steady rider
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Re: Large Helmets

Post by Steady rider »

Chris Juden in 1991 wrote a 5 page article for Cycle touring and campaigning, 'Helmet Buyers's Guide' and it looks like a modern version is required giving all the manufacturers and sizes provided. A simple list could be used, make, size, etc.
tim-b
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Re: Large Helmets

Post by tim-b »

Found this... https://www.headsdontbounce.com/bicycle ... ads/#table
Apologies if already mentioned
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