How much of a windshield is required to 'shape' the air?

[Badot]

With both my helmets if I tip my head back a little (~15 degrees) while riding it gets drastically quieter -- the low booming turbulence goes away completely and there's just a bit of wind noise left, almost like being in a car. I figure I could get a small shield to get the wind moving in a bit of an upward direction to do the same thing. But how big of one do I need?

I'm not looking to be out of the wind at all... in fact I generally like being in the wind. I just need something to give the air a bit more upward flow. Would a small flyscreen do, or will I need something larger?

I'm looking at this one in particular since I don't think it'd look too bad on the bike, but any suggestions are appreciated.

[mcg2000]

Well, what sucks is that you have to go pretty large if your looking to "shape" the air flow around you. You have to consider that not only is the air moving up the windshield, but as soon as it leaves the surface, the high pressure is now pushing that air back towards you again. And it's going to effect it very quickly. Not only that, but you also have the low pressure behind the windshield pulling the air back.

However I'm not talking from ownership experience, at least on a sport bike. I had a big windshield on my 1st bike, a cruiser, and it still hit the top of my helmet. Bikes already have the worst drag coefficients of all vehicles, and adding a windshield is going to make it a LOT worse. Frankly, I'd just stick with what you have and forget the convenience of less wind noise.

[Janx101]

Hrrmmm ... Ok so I realise you have an e ... And probably want to keep it that way apart from screen... But for a comparison point .. I have a 06 F ... The standard screen on that keeps the air buffet off me mostly... (I'm 5'11") .. I did have the bike naked last year and the head/shoulders difference is noticeable with the fairing back on... The turbulence is not gone! .. But pretty good... A mate has one of this double bubble zero gravity whatever thingies on his and he reckons its even better .. But he is shorter by 3" ...

Several lads on here have changed or altered to other screens...

Rake angle is just as important as shape and height ...

Personal preference in the end I guess

[gsJack]

I did my first 250k miles on 4 Hondas and the first 50k miles on my 97 GS all with a big Plexi 2 size windshield.  All smaller 400-750cc bikes.  The only time I ever hit triple digits on a bike was in the mountains of upper NY state and that was with a big Plexi 2 on my 97 GS.  After that for trips to the Smoky Mtns I put a Spitfire shield on and ended up changing shields spring and fall for the last ten years.  We did 400 mile first and last days on the Interstate on those trips at 70-80 mph indicated.  I found the Spitfire with a FF helmet quite comfortable on the Interstate at those speeds and an absolute delight compared to the big Plexi 2 shield on high wind days.  In the rain and in Jan-Feb here in NE Ohio the big Plexi wins hands down.

There's a line of turbulance off the top of a shield that is extremely annoying if it hits you right in the face and it took some adjustment to height and rake to get the Spitfire comfortable at speed with the line of turbulance hitting about neck/shoulder high.  The line was/is over the head with the big shield on the GS but still a problem on cruisers,  we sit much closer to the shield than one does on most cruisers. I was 6' 2" for decades and wore 30" inseam pants so I was short limbed and long in the middle and sat rather high.  I'm down to 5' 11" now and declining but most of you don't have to worry about that for a few decades yet.      A shield needs to fitted to your size to be right for you.

[Badot]

Hmm, too bad there's no 'try before you buy'. I'm 6'7" so I probably can't go off of others' experience too much.

I may try to build my own, I can't really justify spending $60+ on something I'm not even sure will suit my needs.

[Higgins13]

Neat looking windscreen, I like the blue one.

[Kiwingenuity]

I see in the past that a few members have purchased the zero gravity "double bubble" screens - How have these worked out?  I have a real issue with the stock windscreen directing rain to the middle of my jacket which eventually soaks through..

I am a little concerned about increased issues with handling in wind if I fit a larger screen - we get an awful lot here, and it quite often gets between 70-100kph gusts (43-62Mph for those are not so familiar with SI). Is the larger screen more noticable in wind?

Any comments would be welcome

Cheers

[Bluesmudge]

I have the zero gravity touring screen. It takes a lot of the air off my chest which is nice, but I notice more wind noise because it dumps all the air right into my helmet instead of below my neck. Maybe some day I'll add something to it to get more wind coverage. I commute every day in Seattle so I welcome more wind/weather protection.

Here are two options I have considered trying:
http://gstwins.com/gsboard/index.php?topic=53630.0
http://gstwins.com/gsboard/index.php?topic=52196.0

[jestercinti]

Electrojake has a crazy contraption of a windshield for his F model.

Search for it. It's quite the setup.

[adidasguy]

I see in the past that a few members have purchased the zero gravity "double bubble" screens - How have these worked out?  I have a real issue with the stock windscreen directing rain to the middle of my jacket which eventually soaks through..

I had the double bubble. For me, it caused constant popping of the air. I switched to the sport touring and the popping went away.
A lot depends on:
1. Where the air goes
2. How tall you are
3. Where your body is based on the style of handle bars you have.

[Kiwingenuity]

Thanks everyone - I may see if they have a sport touring model available.  I have a stock 2007F and riding position seems fairly uprightish.  Worst case I will switch between stock and aftermarket screen during seasons.

I see in the past that a few members have purchased the zero gravity "double bubble" screens - How have these worked out?  I have a real issue with the stock windscreen directing rain to the middle of my jacket which eventually soaks through..

I had the double bubble. For me, it caused constant popping of the air. I switched to the sport touring and the popping went away.
A lot depends on:
1. Where the air goes
2. How tall you are
3. Where your body is based on the style of handle bars you have.

[utzguy]

If you're trying to punch a person-sized hole in the air it take quite a bit. If you just want to clean up the air, it doesn't take much at all.
I made this little screen for mine and it changes the rough, buffeting air into a more steady flow over my helmet. Much easier on the neck. But my GS is an E and started with no screen at all.
Making a screen is not hard if you don't get too fancy with the curves, but it does take a little practice and patience to learn. You may sacrifice one or two in learning to do it right, so it may not end up cheaper than buying one, but you end up with what you want and you can say "I made it myself".

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[Funderb]

If you're trying to punch a person-sized hole in the air it take quite a bit. If you just want to clean up the air, it doesn't take much at all.
I made this little screen for mine and it changes the rough, buffeting air into a more steady flow over my helmet. Much easier on the neck. But my GS is an E and started with no screen at all.
Making a screen is not hard if you don't get too fancy with the curves, but it does take a little practice and patience to learn. You may sacrifice one or two in learning to do it right, so it may not end up cheaper than buying one, but you end up with what you want and you can say "I made it myself".

PLEASE TELL ME HOW. That screen is EXACTLY what I've been looking for. 
AAH!

[Janx101]

dunno how he did it... but i would... make 2 piece mold (upper/lower) with timber blocks so you can adjust till you happy... get perspex or lexan or whatever sheet and stick it in oven on low heat till it gets all soft... but not too hot! .. using gloves or tongs lay sheet in lower half of mold and use upper half of mold to press down and clamp till its cool.... mark and trim final shape with nibbler or bandsaw, smooth edges with fine file, smooth edges more with fine grit paper, mark and drill the mount holes, polish the whole thing with some urethane car polish .. set it on your desired mounts (that you also prepared earlier) ... bolt down and go for a ride... adjust the rake and such a little bit at a time till it suits you best!!...

easy really!   

[Janx101]

oh and UTZ ... that is a schmicko looking shield for a handmade job!! 

[BockinBboy]

Dry humor made a windscreen that turned out pretty good. Just need something to punch the wind first and give it direction.

http://gstwins.com/gsboard/index.php?topic=61724.msg718506#msg718506

- Bboy

[utzguy]

Janx: Thanks! I still consider it a beta version, but it'll do until I have dealt with other issues.

The molds and oven technique would probably work better in the end. I cut mine out with a sabre saw, then used a piece of wood with a rounded corner and a heat gun to bend it to shape. In retrospect, I should have done the bends first, then cut the shape. As I said, there is learning in doing. The plastic is polycarbonate, which is sold under various names. Some other plastics are easier to form but not as tough. If you do use a heat gun, be patient! If you get a spot too hot it will bubble (there are some small ones in mine screen). The oven technique should heat the plastic more uniformly and help avoid this (plus it's easier to be patient when you are not sitting there moving a heat gun back and forth).