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| kawashima |
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kawashima
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 Posted: 22:38 - 03 Apr 2020  Post subject: how different is a lighter helmet? edit:bought Shoei Z7(NXR) |
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I have Shoei GT-Air (not 2) weighs about 1600g.
This seems to be one of the reason I still feel neck pain when riding.
(I have non good C5/C6 due to bad habit of cracking neck)
Would lighter helmet help ease this?
I have two possible choice.
1) Shoei Z7(NXR in UK) weighs about 1400g but expensive
2) Jet Lid for 125cc weighs about 920g and cheap but not safe
If I instantly buy 1) and still feel neck pain I feel awkward.
So Testing 2) and confirm I don't feel pain with super light helmet before buying 1) seems to be a good idea for me.
1)Z7 (NXR)
https://www.shoei.com/products/assets/model_img_466_471_01.png
2)125cc Lid
https://www.ysgear.co.jp/share/images/Products/907913247W00/907913247W00.jpg
p.s. I recently bought Serow250. Wearing helmet for 125cc is not illegal but not suggested.
____________________
own:2020 Serow 250
owned: 2012 YB125SP, 2008 TDM900, 2005 W650, 2002 LS125R, 2002 CB400SF, NS50F, C50 / Trip to UK(2009), Hokkaido touring(2013)
Last edited by kawashima on 13:47 - 04 Apr 2020; edited 2 times in total |
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| stinkwheel |
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stinkwheel
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Posted: 23:10 - 03 Apr 2020  Post subject: |
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I think shell size/frontal area is more important than weight.
The faster you are going, the more important it is because drag increases with speed squared (2x speed = 4x drag) because it is based on the frontal area of the helmet.
I often do quite high speed riding for long distances and I really notice neck muscle fatigue with a larger shell helmet.
Often (not always) a cheaper helmet will use the same shell size across the range, just with more or less padding inside to accommodate different head sizes. The more expensive brands use a different shell for each size.
Do they have Airoh helmets where you are? They are fairly inexpensive, generally quite low-profile and many of their models use 3 different shell sizes.
Of course, you should really address the real problem which is your posture  I practice Tai Chi which is very useful for developing good posture and alignment but I'm not sure if it's practiced much in Japan? Yoga and Pilates are two other practices you might find useful if you can find a good instructor.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles. |
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| Kentol750 |
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Kentol750
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| kawashima |
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kawashima
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| Posted: 23:37 - 03 Apr 2020 Post subject: |
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| stinkwheel wrote: | I think shell size/frontal area is more important than weight.
The faster you are going, the more important it is because drag increases with speed squared (2x speed = 4x drag) because it is based on the frontal area of the helmet.
I often do quite high speed riding for long distances and I really notice neck muscle fatigue with a larger shell helmet.
Often (not always) a cheaper helmet will use the same shell size across the range, just with more or less padding inside to accommodate different head sizes. The more expensive brands use a different shell for each size.
Do they have Airoh helmets where you are? They are fairly inexpensive, generally quite low-profile and many of their models use 3 different shell sizes.
Of course, you should really address the real problem which is your posture I practice Tai Chi which is very useful for developing good posture and alignment but I'm not sure if it's practiced much in Japan? Yoga and Pilates are two other practices you might find useful if you can find a good instructor. |
Thanks for your input Stinkwheel.
My GT-Air has so big shell not only it's heavy.
Z7(NXR) seems to have four different shell for each size.
I agree cheaper helmet use smaller size shell and less inner. I tried above cheap lid and it was so thin and felt unsafe.
I've checked Airoh helmets. Famous helmet for motocross made in Italy and looks nice and light, but I couldn't find them being sold here.
I will try to keep good posture too.
I'm going to test some lids at motorcycle parts shop today. 
____________________
own:2020 Serow 250
owned: 2012 YB125SP, 2008 TDM900, 2005 W650, 2002 LS125R, 2002 CB400SF, NS50F, C50 / Trip to UK(2009), Hokkaido touring(2013) |
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| kawashima |
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kawashima
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| Posted: 23:55 - 03 Apr 2020 Post subject: |
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| Kentol750 wrote: | Have used a gt air and a neotec 2.... and before meh people, a neotec, an xr 1000 and an x spirit 3.... prefer my bell carbon over them all because it's lighter. But, lighter moves my head around more at speed. I prefer feeling safe and knowing that when I crash, my head's ok. Rest of it is down to how cool it looks. |
Thanks for your comment.
Bell carbon looks very cool light helmet. They had HP for here too.
https://www.bellracing.jp/index.html
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own:2020 Serow 250
owned: 2012 YB125SP, 2008 TDM900, 2005 W650, 2002 LS125R, 2002 CB400SF, NS50F, C50 / Trip to UK(2009), Hokkaido touring(2013) |
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| stinkwheel |
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stinkwheel
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Posted: 00:21 - 04 Apr 2020  Post subject: |
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I think the ones in that link are car racing helmets? The visor size and visability is much reduced compared to a motorcycle helmet.
Car helmets are also designed to cope with multiple impacts in the same accident and penetrating objects (like in a rolling car) where a motorcycle one is designed to cope with one big impact (when you hit the ground) and be destroyed.
As such, the car helmet will transmit more energy to your skull in a single impact accident.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles. |
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| Teflon-Mike |
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Teflon-Mike
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| Posted: 00:24 - 04 Apr 2020 Post subject: Re: how different is a lighter helmet? |
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| kawashima wrote: | 2) Jet Lid for 125cc weighs about 920g and cheap but not safe
p.s. I recently bought Serow250. Wearing helmet for 125cc is not illegal but not suggested. |
Its NOT a 'safety helmet', its an effing CRASH HAT... none of them are 'Safe'. Sorry but modern bit of PC indoctrination that grates; we got ordered to stop calling Crash hats crash hats or Skid Lids, 'cos it sounds scary, and evokes ideas of getting hurt and a CRASH HAT is supposed to take away the hurt! No it wont, its an effing crash hat, and CRASHING HURTS! No wanna get hurt.... DON'T CRASH!!! So telling folk its a crash hat and they might crash, and warning them to try NOT to crash, rather than sticking their head in a plastic bucket and thinking alls well and they can crash with abandon, to MY mind seems a better idea... so... I'll call it an effin CRASH HAT if you dont mind!!!
Moving on... WHY the heck should a helmet be any less safe on a 125 than on a 750 or 1000 or a 250 than it is on a 125?.. it just dont make sense.. remember CRASHING HURTS!!! And makes little odds whether you crash a 50, a 500 or a 1500, it still gonna hurt and odds of a head injury are much of a much the same regardless.
Ironically, the idea that the safety is some-how proportional to the engine size, is, if anything, somewhat inverted. If you have a higher cc bike it's probably capable of accelerating harder and going faster, so IF you crash, there is likely to be a bit more kinetic energy involved and an impact could be harder. On the other hand, on a possibly slower bike, probably used on more congested city traffic, and even more likely with familiarity breeding contempt, and even more erroniouse idea that a slower bike 'must' be safer... actual odds of crashing and needing what little comfort a crash hat may offer is likely the greater!!!
Oh-Kay... moving on. I have a few lids, and Following on from the warning that it's not the Sharpe rating that makes a hat any more or less 'safe' and certainly not the bike its being worn above... I have few qualms about wearing my £15 Arashi open face on the 750. My £300 Sharp 'flip' is a dang site heavier... I cant remember the exact weights OTMH but ISTR its dang near twice the mass! Which brings us back sort of on topic.... but the point is that it's not the weight so much as the balance and on the bike, the aerodynamics of the ting that make any difference, really.... and that is little to do with Sharpe ratings or the price on the box.
To wit; the answer if that to all practical extent and purpose the weight of the hat will make but little odds to your pain in the neck problem.
A Comfy hat is a comfy hat, and a practical hat a practical hat, and what works works or not and there's always going to have to be some degree of compromise.
The 'lightest' head-wear you could use would be NO head-wear... heed earlier comment... no crash no need crash hat! Its only IF you crash that it comes into question... and again, no hat is NOT inherently any less 'safe' than something with a 5-star rating... if you crash... for the hat to save you any hurt, head has to hit something! And it has to hit something hard enough that the polystyrene inside actually absorbs some of the impact, but not so hard you aint deaded anyway, and more, a crash hat will only cushion some of the blow to your head... it wot stop you breaking your neck or breaking your legs or cracking ribs..... now the matter becomes significantly accademic.
Slight aside: I started out in School-Boy trials umperty decades ago, not long after the UK compulsory Helmet laws for the road, when the issue was still much debated. When I started in the sport crash hats were mandated for the youth class, BUT interestingly NOT for the adult. It was over a decade until that came along, and for a long while, it was down to the organisers discretion, and entry regs had warnings in them like 'No Hat - No Ride' if the clubs insisted on it.. usually for their event insurance.
However, whilst the matter of compulsory Helmets was still being debated for the road, and muted as being made compulsory, across the board 'off-road', there was a rather interesting argument put forth regarding the mandating of crash hats for youths, and study sited showing that putting children in hats actually INCREASED the likelihood of injury, mainly because of the extra weight on their under developed necks and the added leverage in an accident. Which was all rather intriguing.. but does support the suggestion that a lighter helmet is 'probably' better than a heavier one...
B~U~T the weight alone is but one very small part of the overall equation, but one that is nice and easily measured....
Bottom line... will a lighter hat be more comfy?
Yes, and No and a lot of may-be. Ultimately a comfy hat is a comfy hat, but even then, what's comfy leaning over the handlebars in a a scrunched up sports bike, may not be so comfy leaning back in an armchair cruiser saddle, its STILL very circumstantial.
Pays your money and take your chances, this is NOT a question that can be answered by make and model or brochure specs.
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Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
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Kentol750
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kawashima
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stinkwheel
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kawashima
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Posted: 13:39 - 04 Apr 2020  Post subject: Re: how different is a lighter helmet? |
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| stinkwheel wrote: | | kawashima wrote: |
I bought shouei Z7. |
Seems like a really good option for you. They use 6 different shell sizes and have put a considerable amount of thought into making it slippy through the air.
If I took a rough guess of frontal surface area of a helmet at 0.071m^2 and let's make it have the same drag coefficient as a sphere (a real assumption, I'm not sure how aerodynamic they can be made and I bet none of them are prepared to publish that info).
So the force of wind blast at 60mph is exerting a drag force equivalent to 1.47kg on the helmet. At 70mph, that goes up to 2kg.... At 100mph it's 4.1kg.
As you can see, the aerodynamic drag is just as significant as the weight and can easily exceed the weight of the helmet by a significant amount as speed increases.
So the smaller and more aerodynamic the shell, the lower the force on your neck.
Given I will often cruise at 90-100mph for several hours, I go out of my way to find a very small, aerodynamic helmet. |
Today I've ridden my Serow for about 40miles with the new Z7(NXR) on.
I've noticed that drag force has reduced a lot even at 40-50 mph.
I like this small shell of Z7. And I didn't have any neck pain today  .
Also I bought at a shop which was doing inner pad adjustment service for Shoei lid, it was so lucky because without adjustment I had to choose L size but I could buy M size which has smaller shell than L size. Z7 has minimum air intake and no sun visor but I prefer this to GT Air now. I really did a good purchase.
Thanks for your helpful advices.
Left: GT Air, Right: Z7(NXR)
https://i.imgur.com/b07DRK8.jpg
____________________
own:2020 Serow 250
owned: 2012 YB125SP, 2008 TDM900, 2005 W650, 2002 LS125R, 2002 CB400SF, NS50F, C50 / Trip to UK(2009), Hokkaido touring(2013) |
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Old Thread Alert!
The last post was made 5 years, 97 days ago. Instead of replying here, would creating a new thread be more useful? |
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