[jedd]

I'm 5'5", and currently riding my 650 using a 3" taller windshield (from prev owner) vs. the stock one. I've tried putting back the stock windshield, and other than the fact that I can see over the top edge of the stock windshield while seated, I find the stock wind is deflecting the wind high enough to swoop right onto or over the top of my helmet. no wind is hitting my eyes. I can live with that.

But with the taller windshield on the 650, I have to see through the plexiglass while seated. I don't mind it really. HOwever, the wind seems to flow much higher above my helmet that, at times, I am wondering whether this is worse than stock, aerodynamically speaking. I've read where some riders experience sonic booms (or something to that effect) at hwy speeds due to wind turbulence building up behind the rider. Does this sound issue happen only with low windshields or tall windshield?

i mainly want to find the best windshield setting for when I ride on the hwy, doing between 75-85 mph. IN town, the problem with noise or visibility is a moot issue.

 

[MJR]

It all depends on what you like. At 5'8" I found the stock windshield at speed had the lifting effect (like the airflow was trying to pull my helmet up/off). With the Givi I get a bit of push forward feel but I like the added hand protection it provides. I'm right at the peek over/under point on the Givi so I can sit up to look over or drop down to look through. Around here either works but in bug prone areas having a screen to keep them outta your face is nice though you have to clean them off.

 

[Buffalo]

I don't know of any sonic boom noise issues related to windshields. What folks have experienced is buffeting caused by turbulence with the stock screen. This is your head and body being pushed around not a booming noise. With taller screens the issue is a feeling like someone has a hand on your back pushing forward.

As MJR said, it's pretty much a matter of personal preference which you go with. I do recommend having one you can see over if you need to though. If you ride long enough sooner or later you are going to get into a situation where you vision through the screen is compromised.

In my opinion the best way to handle noise issues is ear plugs.

 

[jedd]

OK, I see....it's called buffetting. So does buffetting only occur w/ the stock height shield? Or does the taller WS also produce buffetting, but at a different speed or whatnot?

 

[MJR]

Each windshield will have it's own air flow characteristics and resulting turbulence depending on where you sit in the air envelope they create behind them. Personally I like the looks and hand protection of the Givi but if your riding in warmer weather than more airflow of a smaller shield would probably be better or in colder weather a larger one provides more protection.

 

[JohnK]

For safety reasons it is usually recommended that you be able to just see over the shield when sitting in an upright position with your spine straight.
This would put the shield at nose level and you should be able to see the road over the shield at about 25 feet. During normal sitting you may slouch a little and look thru. However you can sit up straight and look over it should you run into heavy rain or the shield fogs up.

 

[Buffalo]

OK, I see....it's called buffetting. So does buffetting only occur w/ the stock height shield? Or does the taller WS also produce buffetting, but at a different speed or whatnot?

As near as I can tell, most of the buffeting is caused by wind spilling around the sides of the windshield and not over the top so height is somewhat irrelevant. I think the wider width of the aftermarket shields does more to reduce buffeting than the extra height. However as MJR mentioned it is really different with each person. Aerodynamics depend not just on the frontal area but the total shape of the object.

Since each of us is a different size and sit on the bike a different way the aerodynamics of how the air moves around us is different. Move you arms in or out, move your knees in or out, sit up straighter so slouch down, all these things will change the air flow. Adding a top case or strapping luggage to the top of the seat can do the same thing. There is no one answer that is true for everyone. You will have to do some experimenting and see what works best for you.