Helmet Safety vs Aerodynamics
Here's what Grayham Rayne has to say about todays helmet options, which i found very informative;
"the charly visor fits pretty good, but needs some tape. You definitely loose some useability since you can't flip your visor up, but if you can forego looking ultra-sleek then this is the helmet.
Once you take off the visor of the stock helmet, the form factor for the bell drop is like inflating the surface area of a charly by .5" to 1" all around. It IS bigger, but it is also much, much safer. The helmet was made specifically for downhill mountain bike racing and spoke volumes to me.
When Justin Metcalf was injured, the road wasn't what did the damage, it was the trees and rocks off the side of the road. While Charly's are a great shell, and in most racing situations I believe they are safe for road impacts. It is the non-road impacts I worry about and was confronted with after Justin's accident.
So, the shopping began and the Bell Drop was what I found to be best.
To outfit it for longboarding was easy. A charly visor fits with electrical tape and the aero fairing is dead simple, but takes some revision to make it fit just right. The important thing to mention here is that the emphasis of building this helmet was to make something FAST, but very safe. The Bell drop was a starting point. Adding a visor and sealing up vents with electrical tape was step #2. The final step was really to point our that aerodynamics do not have to come at the expense of safety.
The aero helmets on the market right now have some fatal flaws that we should all be aware of:
-Paragliding helmets are made for light impacts. This is ok for road impacts, but trees - bad news.
-RISCH and LID TECHNOLOGIES: This is a topic I haven't breached because it is opinion, but it should be voiced. DON'T TRUST HELMETS MADE BY SKATEBOARDERS! they may look good, but they have not been tested. The guys behind these helmets NEED to invest in proper testing before exposing themselves to liability, and to ensure that their trusting audience isn't going to break their neck. This is a SERIOUS warning. DO NOT BUY THESE HELMETS. Pressure the manufacturers into extensive testing.
Also, I have concern for Concrete Wave for publishing ads that advocate helmet use, yet also publish articles about untested and potentially unsafe helmets (RISCH).
My primary concern about these helmets is the testing - it hasn't been done, or if it has there is no rating. The second concern is their usability. Before embarking on making my helmet fairing I read a few books on aerodynamics and my conclusion is that shoulder fairings are completely useless. Shoulders are aerodynamic on their own. In the dynamic nature of a downhill skateboarder the rider changes stances and in many situations shoulder fairings add additional surface area (increased drag if you are not in a tuck). Complicating matters is of course the fact that there are shoulder fairings. They get in the way and in the case of a crash, my prediction is that before long we will see broken collarbones as a result of these shoulder fairings.
What I did glean from my aerodynamic studies is that on Aero Helmets the tail fin is adding a significant amount of benefit. In the case of aero helmets this is a fixed composite construction. This concerns me. In event of a crash we do not know what outcome this will have on the rider. The fact that most helmets on the market for virtually EVERY sport allow the neck to move in the event of a crash is testimony that fixed tails are a bad idea.
My SOLUTION: For the fairing I used a piece of snowboard P-Tex because we have a lot at the shop and it fit my safety requirements. This was used because if taped on it will crush in the event of a crash, leaving the helmet to take any impact. I made 3 revisions to the fairing before it worked really well for me and as a comparison test I have ridden a LID helmet and had similar benefits speed-wise in comparision with a charly, or a Bell Drop sans fairing".
this is what he uses
thoughts?
"the charly visor fits pretty good, but needs some tape. You definitely loose some useability since you can't flip your visor up, but if you can forego looking ultra-sleek then this is the helmet.
Once you take off the visor of the stock helmet, the form factor for the bell drop is like inflating the surface area of a charly by .5" to 1" all around. It IS bigger, but it is also much, much safer. The helmet was made specifically for downhill mountain bike racing and spoke volumes to me.
When Justin Metcalf was injured, the road wasn't what did the damage, it was the trees and rocks off the side of the road. While Charly's are a great shell, and in most racing situations I believe they are safe for road impacts. It is the non-road impacts I worry about and was confronted with after Justin's accident.
So, the shopping began and the Bell Drop was what I found to be best.
To outfit it for longboarding was easy. A charly visor fits with electrical tape and the aero fairing is dead simple, but takes some revision to make it fit just right. The important thing to mention here is that the emphasis of building this helmet was to make something FAST, but very safe. The Bell drop was a starting point. Adding a visor and sealing up vents with electrical tape was step #2. The final step was really to point our that aerodynamics do not have to come at the expense of safety.
The aero helmets on the market right now have some fatal flaws that we should all be aware of:
-Paragliding helmets are made for light impacts. This is ok for road impacts, but trees - bad news.
-RISCH and LID TECHNOLOGIES: This is a topic I haven't breached because it is opinion, but it should be voiced. DON'T TRUST HELMETS MADE BY SKATEBOARDERS! they may look good, but they have not been tested. The guys behind these helmets NEED to invest in proper testing before exposing themselves to liability, and to ensure that their trusting audience isn't going to break their neck. This is a SERIOUS warning. DO NOT BUY THESE HELMETS. Pressure the manufacturers into extensive testing.
Also, I have concern for Concrete Wave for publishing ads that advocate helmet use, yet also publish articles about untested and potentially unsafe helmets (RISCH).
My primary concern about these helmets is the testing - it hasn't been done, or if it has there is no rating. The second concern is their usability. Before embarking on making my helmet fairing I read a few books on aerodynamics and my conclusion is that shoulder fairings are completely useless. Shoulders are aerodynamic on their own. In the dynamic nature of a downhill skateboarder the rider changes stances and in many situations shoulder fairings add additional surface area (increased drag if you are not in a tuck). Complicating matters is of course the fact that there are shoulder fairings. They get in the way and in the case of a crash, my prediction is that before long we will see broken collarbones as a result of these shoulder fairings.
What I did glean from my aerodynamic studies is that on Aero Helmets the tail fin is adding a significant amount of benefit. In the case of aero helmets this is a fixed composite construction. This concerns me. In event of a crash we do not know what outcome this will have on the rider. The fact that most helmets on the market for virtually EVERY sport allow the neck to move in the event of a crash is testimony that fixed tails are a bad idea.
My SOLUTION: For the fairing I used a piece of snowboard P-Tex because we have a lot at the shop and it fit my safety requirements. This was used because if taped on it will crush in the event of a crash, leaving the helmet to take any impact. I made 3 revisions to the fairing before it worked really well for me and as a comparison test I have ridden a LID helmet and had similar benefits speed-wise in comparision with a charly, or a Bell Drop sans fairing".
this is what he uses
thoughts?
Tags: Aerodynamics, Helmets, Safety
Views: 1328
Replies to This Discussion
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Premium MemberPermalink Reply by Jacko on -
graham knows his shit i'll tell you that much. his helmet is the best idea ive seen to date, as far as safety/aerodynamics goes... its such a great fairing ive been wanting to put up pics of it for ages but i couldnt find any... the fairing itself is stiff, but you can bend it really easy coz it is thin, and then it just snaps back into place. so if he crashed the fairing would just fold underneath the helmet then the helmet will do the rest of the work.
I think its genius...
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ASRA AdminPermalink Reply by Bugs on -
Yep I agree in general. Whether you're travelling at 5km/h or 100km/h your head hits the road with the same force. It's trees, large rocks and kerbs that can do the damage. Any rigid fairing is going to mess with the way your head naturally rolls in a crash, and that seems likely to increase the rotational force on your brain, which is suspected to be one of the main causes of head injuries.
So if you have a fairing it should be collapsable. And the cushioning of a helmet is only relevant for hitting objects that, unlike the road, are not in the same plane you are travelling on.
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Permalink Reply by nick on
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shit yeah. Bell Drop ftw.
Seriously though. For any prospective helmet buyers the bell drop is amazing. Great visibility light and fairly aero.
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ASRA AdminPermalink Reply by Bugs on -
JudgeK said:I think the speed your head hits the ground is very important...
Not just the speed but the direction. If your head is travelling at 100km/h in a direction parallel to the ground, and you then fall over, your head hits the ground with the same force as if you fell over while standing still.
Hitting a tree with your head at 100km/h is likely to kill you regardless of whether or not you're wearing a helmet.
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Permalink Reply by Ben on
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what bugs said,
has anyone used/tested a giro remedy? they are one of the "staple diet" helmets in canada apparently, but i'm wondering how safe they really stack up to be.....
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Permalink Reply by leighgriffiths on
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yeah, i use the giro. haven't had to put it to the test yet, however it feels like a solid helmet. its too beefy for racing in my opinion.
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Permalink Reply by butnugget oldschool fatass on
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specilized downhill moutainbike pro carbon helmets of the best in there range are the go unless your a titearse...
dont be gay, get awsome helmets with sweet graphics..
because its really just all about fun but looking good has also never been more important than atm.....
peace ! bitches! dont be a retard, your allready wearing body suits in pulic.. haha
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Premium MemberPermalink Reply by Dani on -
What helmet do you wear butnugget? Not a cheetahs head??
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doesn't the transport dept. keep a record of all helmets that are green lighted for use in different divisions (MTB, skateparks,motorbike, racing, etc) ?
i thought they did, it'd be interesting to see what they have to say about it.
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Premium MemberPermalink Reply by nathan on -
Ben said:what bugs said,
has anyone used/tested a giro remedy? they are one of the "staple diet" helmets in canada apparently, but i'm wondering how safe they really stack up to be.....
I have a remedy (so does bugs and a few others) They are solid! and not that heavy, Im happy with it, great vision, quite comfy, and has little earholes so u can hear guys coming up beside u! Most guys have fitted polycarbonate visors which tuck inside the lining quite nicely, I have heaps of polycarbonate but have just been too lazy as its pretty fiddly!!
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Premium MemberPermalink Reply by Steve on -
I have the bell drop and its great, really light awesome vision but it is big ( which is one of the reasons I got it , I have been told I have a massive head haha). Another downside is that because of the mouthpeice you have to make a visor that goes on the outside which is a little tricky. If anyone wants a visor template fot the bell drop let me know
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Premium MemberPermalink Reply by Dani on -
Nathan, mate. Make yourself a visor. You will go alot faster without a big parachute on your head catching all the wind.
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