As mentioned, mostly to give a place to hang all the stupid crap those guys are required to carry.

At least some electronics are to prevent cheating, which is rampant in World Enduro and ISDE rally. Also to note, a few Dakar racers have been killed when they were squished through all that metal in the Nav tower in crash.

Having hard parts aimed right at your chest and stomach is something I would never do. I'd rather be lost.

The Dakar guys get up to very high speed, despite running just 450's. In the old days of 1000cc twins, when in Africa, speeds often topped 100 mph for long sections.

Nav towers were half the height they are now. So many riders died every year. They kept lowering engine size over and over. 1000 twin, 650 single, and now
450 single.

Now the tall Nav tower look has become "fashionable" I raced AMA Enduro 8 years, had two computers and a clock, no Nav tower or shield of any kind.
It's all just so stupid now. But KTM have sold this look to the public ... and it's pretty successful ... for now. Trends and fashion come and go. Most Americans have no idea what the Dakar is ... and could care less. KTM have built an entire industry on it.

it now costs over $100K USD to run the Dakar. So, a "rich kids" sport and really only KTM do a full factory effort. With about 70 guys riding KTM ... how can they lose?

bier

Something with a big barn door fairing / screen and a pocket of still air where the rider sits can get to the point where it's a health hazard in really hot conditions. My two hottest days ever on bikes were both on GoldWings, although different models, one naked and one 'screened'. The feeling of riding the screened one in parts of Texas, around Phoenix and through the Mojave was, at its worst, close to being drunk. We had to stop in the Mojave as my wife thought she was going to faint. There's just no air flow at all - presumably what the designers intended.

The effect is a bit like driving a no air con car with the windows open but having to wear all your bike gear. Every other Wing we encountered had some kind of vent set into the screen that they could open when the temperature went up. Despite being able to buy them for $25 my UK brain couldn't see the point. Well I can see it now.

My rough 'how hot do I feel' calculations worked out that the fairing / screen was worth about 7-8C. When the mercury hits 40C in the shade and you're riding in the direct sun, that extra 7-8C you're feeling compared to the bloke on the (mostly) naked bike (riding with us) is a big deal. On the other hand up in Wyoming where it was 0.5C and sleeting that 7-8C bonus and (slightly) drier environment was very welcome. I got damp and chilled. He got soaked and frozen.

Right. Fixed the stock shorty screen to the FZ1S and did a few hundred KM over the weekend. Takeaway:

1) The road noise was maybe better - subjectively it felt that way, but it could be wishful thinking. Certainly was not worse. In that sense, yes, having your helmet in clean air is good for noise.

2) However, it was still not as good as standing up on the pegs. I guess the body of the bike spoils the air enough, and the engine noise drops off severely when you stand up, but standing on the pegs with the shorty screen gave the same effect as with the touring screen - FAR quieter than sitting down.

3) The downside of the shorty screen is the chest pressure; even in this heatwave, where coldness is not a concern (in fact I was wearing a mesh jacket), riding at any serious speed with the shorty screen meant leaning forward into the wind. Whereas with the touring barn door screen, I could sit comfortably upright even at speeds of... er, no, officer, I was not doing anything close to that.

4) Another downside is that with the shorty screen, the helmet's aerodynamics were suddenly important. I was using a Grex G9.1, essentially a rebadged Nolan N90, and at speed I could tell the difference between how it cut through the air and how my Shoei NXR did. Both straightline and, especially, doing shoulder checks at speed. The Grex was not terrible, but it was now A Concern, whereas with the touring screen, it wasn't.

5) What the shorty screen does give you, though, is exhilaration and sense of speed; and more maneuvering confidence. So for purely urban riding, I would actually stick to the shorty. But for extended trips, the barn door is going back on.

sounds like you are getting nearer to a quieter screen.
As I'm sure you know, there are several things you can do that may help the wind noise and buffeting.

Spacers can be used to change the angle of attack.
Height adjustment UP or DOWN can sometimes have a positive affect.

But the best I've used are the various adjustable small air foil extension (laminar lip type screen) that attach to your main screen. They allow adjustment which can reduce or eliminate wind noise.

Companies like MRA, Puig and Laminar Lip all make such small adjustable air foil type screens. Some work, some don't.

https://photos.smugmug.com/Misc-Moto...it_300x300.jpg

https://photos.smugmug.com/Misc-Moto...b/O/images.jpg

Yup, that's exactly what I have, and I've found that the best result is angling the lip to look directly into my visor.

When you're following a lorry you're sitting in a pocket of moving air being dragged along by it, so naturally there is less wind noise. What makes the noise is the shearing action between moving and static air, typically as the air stream going past your helmet meets the non moving air inside it. So unless you've got a real "barn door" fairing that deflects all the airflow over your head, your helmet will be in some kind of moving air.

Personally the only advantage I find with screens is they keep some of the wind load off your upper body, avoiding the "sheet in the wind" effect at speed.

That's not what happens though. Unless you are tailgaiting extremely closely, like the hypermiling car guys, you're sitting in the vortex of extremely turbulent air created by the lorry's passing. The absolute most uncomfortable place to be on a motorcycle is behind a lorry. I'd rather ride through a hailstorm.

The reason I brought it up was that if I stand up on the pegs - putting my head significantly outside any aerodynamic business to do with the body of the bike - it gets really quiet. My helmet is still moving through air, obviously.

You don't need to be that close. In my younger days I used to tailgate lorries on motorways a lot, as I had a low powered bike. The "tail" of moving air behind a lorry extends for about a second of travel (I know that's "too close", but I was young and stupid). Once you get outside of that there is a small turbulent zone as the moving air from the lorry meets still air but pretty quickly you're back into still air. And having done many miles with no screens at all I've never experienced a situation where standing up made any difference to wind noise in the helmet. Maybe this is something to do with the airflow set up by your screen?

Lots of things can cause turbulence. On some other forums guys have got into this in a serious way.

Standing IS is indeed quieter if you have any sort of front cowl or small shield.
On a true "naked" bike, would be less, but still a difference sitting to standing. (I measured this with Audiophile pro equipment)

It's been found that even mirrors and bark busters can add to noise.
Who knew?

But, every bike is different and more importantly, every rider is physically different. They sit on the bike differently, are larger or smaller riders, some hunch forward, some sit bolt upright.

All this affects wind noise and buffeting.

And as mentioned, some helmets are better than others.

TIP: having done an actual helmet noise study for USA Motorcyclist magazine (I did sound recording and analysis) we "discovered" that most noise comes from under your chin.

We used a naked bike (1200 Bandit) same rider for all testing.

So ... a chin baffle can quiet things quite a bit ... if you can fit one in there.

In our testing (from early 1990's) Arai was quietest, Shuberth not for sale in USA at that time. Shoei a close 2nd. things dropped off quickly and dramatically after that.

I used "best in the world" lavaliere mics taped onto riders ears with wind screens. Test rider not happy upon removal!
bier

I fit tall screens to all my bikes. And fit universal screens to any bikes that don't have them if I intend to travel on them.

Having a screen takes A LOT of the fatigue out of long distances. And saves your hearing too.

I have found that the top of the screen needs to be in-line with your chin to displace the air over your head.

Helmets with peaks don't help either. Although, I have a peak.

Try one of these.

https://www.ebay.co.uk/itm/232870529652

But do put something between the clamp and your screen as these cheaper ones can make your screen crack.

when your grandpas were riding horses would they wear windscreen ???

http://45.media.tumblr.com/ff9fd687b...i37so1_400.gif

if hiding behind big screen why not to get into a car then :)

When my grandpas were riding horses, they were also dying of dysentery. You enjoy your self-image there.

I've never ridden a horse that could reach 80mph into a headwind.

There's a few bikes that cant do that either :mchappy: