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Davemc37 |
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Davemc37 Nova Slayer
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pepperami |
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pepperami Super Spammer
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NJD |
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NJD World Chat Champion
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Kawasaki Jimbo |
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Kawasaki Jimbo World Chat Champion
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chickenstrip |
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chickenstrip Super Spammer
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Posted: 00:39 - 21 Feb 2018 Post subject: |
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When I switched to my current choice, it was a revelation. Never had less buffeting from wind, including Shoei and Arai lids I had years ago. And I've ridden the same model of bike with various height of screen with these particular lids - makes no difference, still better than any other lid I've used in that regard. But I wouldn't call them cheap either. What bothers me about answering questions like this though, is if I tell you what lid it is, and you go out and buy one, I just know what will happen ____________________ Chickenystripgeezer's Biking Life (Latest update 19/10/18) Belgium, France, Italy, Austria tour 2016 Picos de Europa, Pyrenees and French Alps tour 2017 Scotland Trip 1, now with BONUS FEATURE edit, 5/10/19, on page 2 Scotland Trip 2 Luxembourg, Black Forest, Switzerland, Vosges Trip 2017
THERE'S MILLIONS OF CHICKENSTRIPS OUT THERE! |
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Kawasaki Jimbo |
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Kawasaki Jimbo World Chat Champion
Joined: 09 Oct 2015 Karma :
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Posted: 01:00 - 21 Feb 2018 Post subject: |
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chickenstrip |
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chickenstrip Super Spammer
Joined: 06 Dec 2013 Karma :
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Posted: 01:01 - 21 Feb 2018 Post subject: |
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No, but that's my preferred gimp suit ____________________ Chickenystripgeezer's Biking Life (Latest update 19/10/18) Belgium, France, Italy, Austria tour 2016 Picos de Europa, Pyrenees and French Alps tour 2017 Scotland Trip 1, now with BONUS FEATURE edit, 5/10/19, on page 2 Scotland Trip 2 Luxembourg, Black Forest, Switzerland, Vosges Trip 2017
THERE'S MILLIONS OF CHICKENSTRIPS OUT THERE! |
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stinkwheel |
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stinkwheel Bovine Proctologist
Joined: 12 Jul 2004 Karma :
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Posted: 01:13 - 21 Feb 2018 Post subject: |
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I wear a very cheap airoh lid which has a tiny shell. Catches the wind less and causes a lot less neck strain over longer journeys. A mate commented that it looks like it was painted on. Super noisy though.
Safety, meh. Look at any objective helmet effectiveness tests and price doesn't seem to come into it. In fact, often cheap lids do best in energy transmission tests because they tend to smash to bits on impact.
Helmets don't help as much as most people seem to think. Try not to fall off and if you do, try not to land on your head. I wear one mostly to keep the wind and rain off. You ever tried to do 100mph without a helmet on? You can't keep it up for long. ____________________ “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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chickenstrip |
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chickenstrip Super Spammer
Joined: 06 Dec 2013 Karma :
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Posted: 01:20 - 21 Feb 2018 Post subject: |
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stinkwheel wrote: |
Helmets don't help as much as most people seem to think. Try not to fall off and if you do, try not to land on your head. |
Except to say that I have scraped several ( ) helmets in accidents. I still have a face It ain't very pretty anyway though ____________________ Chickenystripgeezer's Biking Life (Latest update 19/10/18) Belgium, France, Italy, Austria tour 2016 Picos de Europa, Pyrenees and French Alps tour 2017 Scotland Trip 1, now with BONUS FEATURE edit, 5/10/19, on page 2 Scotland Trip 2 Luxembourg, Black Forest, Switzerland, Vosges Trip 2017
THERE'S MILLIONS OF CHICKENSTRIPS OUT THERE! |
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M.C |
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M.C Super Spammer
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DJP |
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DJP Crazy Courier
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stinkwheel |
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stinkwheel Bovine Proctologist
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Landy10 |
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Landy10 Renault 5 Driver
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Bozzy. |
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Bozzy. Scooby Slapper
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Polarbear |
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Polarbear Super Spammer
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Evil Hans |
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Evil Hans World Chat Champion
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M.C |
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M.C Super Spammer
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Bozzy. |
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Bozzy. Scooby Slapper
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hellkat |
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hellkat Super Spammer
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Bonnie Lad |
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Bonnie Lad Nitrous Nuisance
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NJD |
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NJD World Chat Champion
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M.C |
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M.C Super Spammer
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TheGazWaz |
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TheGazWaz Nitrous Nuisance
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Teflon-Mike |
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Teflon-Mike tl;dr
Joined: 01 Jun 2010 Karma :
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Posted: 17:05 - 02 Mar 2018 Post subject: |
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The Aerodynamic 'efficiency' of a shape, is measured by its cD or co-efficient of drag. An index that compared the shape of an object to a perfectly 'streamlined' teardrop, and a perfectly unstreamlined brick... in relation to its length and frontal area, to derive a pure 'index' a number with no dimensional units, like height, width or weight... A-N-D... to all practical extents and purposes its almost utterly irrelevent!
The drag-force exerted on an object moving through a fluid, is most significantly proportional to the objects frontal area... more area, more force. Next, on the density of the fluid... denser the fluid, more force to move it. Then on the speed of the fluid; faster the fluid moves, more has to be shifted by the object in any period of time, so more force... all pretty simple stuff.
Air... has a density that is pretty constant. Changes a bit depending on the humidity level, and you can add a bit of rain into that, but in the real world its density is pretty much constant.
Speed? A motor-vehicle, may crawl along at under 20mph on suburban streets, limited by council signs, and may get up to the 70mph allowed by other council signs, before they start getting worried by yellow boxes or blue lights, and continue up to maybe around 120mph, when fear of losing hard won licences tends to start to take effect. On a track, where yellow-boxes and blue lights don't influence things, speeds of perhaps 180mph or more might occasionally be attained.... the range of wind-speeds a person on a motorcycle may experience though, is pretty limited and constrained, more often to up to about 60mph, where even very big differences in measured Aerodynamic Efficiency or cD makes very very very little real difference to drag compared to everything else.
Frontal area... probably the biggest variable in this little trilogy... how big is your head? A-N-D sticking a hat on it is only going to make it bigger, so subject to more drag.
Here, is about the only place 'expensive' helmets may start to win over cheaper ones, where manufacturers of more expensive hats may have a range of shell sizes they pad down to fit different head sizes.... but still some-what pot luck whether you win on that score.... if you have a middle-sized head and are lucky that a middle sized shell size sleeved to fit it has a smaller frontal area than if you have a little head in a hat with a lot of padding to sleeve a bigger shell size, you 'may' get a little less drag..
But, in the real-world, wind comes from all directions, not just straight ahead; and unlike a wind tunnel where an artifact is bolted to the tunnel floor pointing directly along the axis of flow.... we move our heads...... a perfectly tear-dropped ski-jumper or speed-cyclists helmet is no-where NEAR as aerodynamic, if they turn their head to look side-ways or over their shoulder! And that is before you start to consider 'turbulence' wind buffeting in any and all directions off other obstacles, like a motorbike fairing, even in a wonderfully idealized wind-tunnel model.
So, short answer, is that the 'aerodynamics' of a motorcycle crash hat make bog all practical odds to anything! There are simply too many variables in the equation, and so many more of them so much more influential than aerodynamic cD in any one 'plane' of travel.
As to buffet... now we are considering not so much the actual force the hat experiences, but how much it moves about on your head in travel....
We are now looking at a model more closely related to suspension systems than aeroplanes, and how much 'bumping' you experience driving accross a plowed field on a tractor with little more than a sprung seat, compared to say a Land-Rover crossing a smoother grasy pasture with cart-springs, or down a bit of corporation road, with pot-holes, in a Bentley!
Little asside, interestingly, in years of off-roading trials bikes and Land-Rovers, the only place I have suffered a suspension failure was taking the dang Landy to an MOT down council maintained tarmac! Welsh tracks did not bother its springs! Err... do we count lost ball-joints on an MG metro on the by-=pass as suspension failure?! Humm... still!
Point is, its SO cirtcumstance dependent, that the aerodynamics of a lid, as measured in a lab are almost completely irrlevent, the shape of a hat is almost inconsequential to its size, and both to how fast you go or how 'blustery' ambient weather conditions.
Hint... you want to suffer less drag, more les buffet, you will get more reduction in ANY situation by SLOWING DOWN, and only a couple of mph, than you will almost any facet of design!
When you look at the design facets of motorcycle crash helmets FIT IS ALL!
In any sircumstances, how closely the hat fits, the space or lack-off between hat and head for wind to grab and tug at, will make more difference than its shape or cost.
There 'may' be some small difference in how much 'complience' a hats padding has, and here a more expensive hat is likely to have better pading that limits movement more, but more significantly, it is likely that that padding is just more durable, and will over time relax les than in a cheaper hat...
Which is where more expensive hats are more likely to score, they tend to last longer, so practically you will probably experience less buffeting, les often in one, than a cheper hat thats gone soft on you... but still in the lap of pretty much, A-N-D the biggest influence remains how good a 'fit' you got to start with, then how blustery the weather, A-N-D how fast you try go.....
Remember, a 3bhp moped can push a person sized shaped object through air at around 30mph. Takes about 9bhp for a 125 to push that same person shaped and sided object through the same air at 60mph, and around 27bhp to shove still the same sized snd shaped person-like object through air at 90mph.... ie, at twice the speed you are subject to the the force squared. That is how aerodynamics work.. with the same sixed and shaped object, you will always get far bigger difference from a change of speed, than you will from a change of frontal area, and even that, more than any question of cD factor!
Basically the answer to the question is that its pot luck, and there's no guarantee that a more expensive hat will be less buffeted than a cheaper one.. there are just far too many other variables in the equation.
But you 'probably' stand a better chance! ____________________ My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
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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Enduro Numpty |
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Enduro Numpty Could Be A Chat Bot
Joined: 31 Oct 2012 Karma :
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Posted: 21:39 - 02 Mar 2018 Post subject: |
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After 10 years of crashing in Scottish Enduros I think I can speak with a bit of authority on the effectiveness of helmets. I've nutted trees, bikes, handlebars, peat bogs, dry stone dykes, fence posts, other helmets and just about anything else that it's possible to nut on an enduro course. Like Chickenstrip, I ain't that pretty but after trashing 6 helmets in 10 years I'm just glad that my only head was in a helmet .
It is of course better not to crash |
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Old Thread Alert!
The last post was made 6 years, 56 days ago. Instead of replying here, would creating a new thread be more useful? |
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