Buffeting or Turbulence from the Windscreen

[MagicSquirrel]

On 6/7/2020 at 9:33 AM, Aleksandar13 said:

This is the screen from power bronze, like mentioned before sport screen is a life saver for me.. Clear air and no more buffeting at 196cm tall with rally seat as well. 

Next on the list side wings

Most modern low screens seem to have a lower bit at the middle and 'shoulders' on edges.
I was wondering if it would be worth doing the same with my DIY molested Ermax screen.
Any idea what's the logic behind having the lower section in the middle?

[Jonas]

37 minutes ago, MagicSquirrel said:

Most modern low screens seem to have a lower bit at the middle and 'shoulders' on edges.
I was wondering if it would be worth doing the same with my DIY molested Ermax screen.
Any idea what's the logic behind having the lower section in the middle?

The only thing I can come up with is that buffeting can become strong on a lighter motorcycle in faster speeds. Buffeting is the turbulent wind trying to even out different pressures front-side-behind the screen. Buffeting can potentially be destabilizing at higher speeds if also the wind is shifting.

 

??? Only a theory. On my older bikes, I had no screen at all, T/ is my sec. with screen.

[Aleksandar13]

45 minutes ago, MagicSquirrel said:

Most modern low screens seem to have a lower bit at the middle and 'shoulders' on edges.
I was wondering if it would be worth doing the same with my DIY molested Ermax screen.
Any idea what's the logic behind having the lower section in the middle?

I think it has something to do with Vortex effect ... turbulent wind get deflected by the side longer pieces away from the rider ... just a presumption.

 

Aleks

[REDHORSECA]

Can someone help me out and measure the side wind screens for me please. I don't have my T7 yet.

 

I want to vinyl wrap the side wind screens and I want to make sure I order a piece big enough.

 

Thanks, much appreciated!.

[CaptainBackfire]

@Alexandar13 Hi, im 193 cm, (about 6.4) Just got my T7. And, yaikes the wind noice is BAD. Standing up and it's all fine. I think I am going your way with the screen and perhaps a rally seat. Have you tried the low screen without the rally seat?

[Aleksandar13]

1 hour ago, CaptainBackfire said:

@Alexandar13 Hi, im 193 cm, (about 6.4) Just got my T7. And, yaikes the wind noice is BAD. Standing up and it's all fine. I think I am going your way with the screen and perhaps a rally seat. Have you tried the low screen without the rally seat?

Tried both with rally seat and without... Its far better with the rally seat but a good improvement over stock anyway.. I'm loving mine now... Couldn't hear my thought at 70mph before. 

Aleks 

[Colddog]

Just got this on this morning for the ride in to work.  Buffeting is gone with the extra width and height, can hear the tunes with earplugs in now at highway speeds!  Givi 2145S model, ordered from Ebay, comes from Italy through a shop called shop.pogliani.  Fast shipping with everything well packaged for the trip, seems to be a great bunch of folks there!

   I was wearing my loudest helmet on the morning ride, got great hopes that this will be my long distance screen for the ride to where the riding is!  Short original screen will either be modded, or I will make a lexan mini screen for snotting around in the bush and mud.  With the 4 screws holding the screen on, it is a quick exchange to swap them as the little screen can be carried in the tail bag if wanted.

[CaptainBackfire]

On 6/22/2020 at 1:30 PM, Aleksandar13 said:

Tried both with rally seat and without... Its far better with the rally seat but a good improvement over stock anyway.. I'm loving mine now... Couldn't hear my thought at 70mph before. 

 

Ok, så the bronze screen is ordered and it appears I'm taking the rally seat out of moto3:s hands

Thanks Aleks for the tips. Now I just need to hold off the urge to get the sm moto rims. Great writeup. Knowing myself, I will get those rims at some point.

 

@Aleksandar13

Edited June 24, 2020 by CaptainBackfire
Got the quoting wrong

[Aleksandar13]

3 minutes ago, CaptainBackfire said:

 

Ok, så the bronze screen is ordered and it appears I'm taking the rally seat out of moto3:s hands

Thanks Aleks for the tips. Now I just need to hold off the urge to get the sm moto rims. Great writeup. Knowing myself, I will get those rims at some point.

 

@Aleksandar13

A picture to help take the decision...  might be in order or more than just one ..  

[CaptainBackfire]

VERY nice! It totally looks factory! Yamaha will have to produce that at some point

[CaptainBackfire]

Can't stop starring at those pictures... That is totally the best looking bike north of the crouch rockets!

[CaptainBackfire]

On 6/23/2020 at 4:04 PM, Colddog said:

Just got this on this morning for the ride in to work.  Buffeting is gone with the extra width and height, can hear the tunes with earplugs in now at highway speeds!  Givi 2145S model, ordered from Ebay, comes from Italy through a shop called shop.pogliani.  Fast shipping with everything well packaged for the trip, seems to be a great bunch of folks there!

   I was wearing my loudest helmet on the morning ride, got great hopes that this will be my long distance screen for the ride to where the riding is!  Short original screen will either be modded, or I will make a lexan mini screen for snotting around in the bush and mud.  With the 4 screws holding the screen on, it is a quick exchange to swap them as the little screen can be carried in the tail bag if wanted.

I @Colddog How tall are you and what seat are you using? I have ordered the rally seat and a low sport screen. I figure that to be my goto nr1, but for weather protection, it would be nice to have a backup. When measuring I kind of figured that I needed minimum 150 mm to get the wind over the helmet with the rally seat. Depends greatly on stature of course... so how tall are you?

[Richard]

On 10/2/2019 at 1:44 PM, ahamay said:

I have read that the stock handguards are ineffective. What say you all? Do they not deflect enough cold wind or rain?

My hand guard hasn't broken yet but the bars are bent on both sides and the clutch lever bent like a noodle, but did straiten without breaking.

Falls were first gear or stoped and dropped. 

Looking for bars and bark busters. Not much good for off road if your bike can't fall over without breaking and possibly leaving you stranded.

Any suggestions for bars or levers.

[Colddog]

5 hours ago, CaptainBackfire said:

I @Colddog How tall are you and what seat are you using? I have ordered the rally seat and a low sport screen. I figure that to be my goto nr1, but for weather protection, it would be nice to have a backup. When measuring I kind of figured that I needed minimum 150 mm to get the wind over the helmet with the rally seat. Depends greatly on stature of course... so how tall are you?

I'm 1.83m tall with 34" (.86m) inseam.  So far the screen is 90% what I'm looking for, I have a T7 adjuster kit coming so I can fine tune it now.  I have a calm bubble of air, and the buffeting from the sides has been negated, even in crazy cross winds I can tell the improvement.  There is one more size taller yet than this one, but it is really quite good already.

  I made a screen to try some different sizing, liked it a lot but it was not wide enough to eliminate the side buffeting as much as I wanted.

I do have one more tall screen to try from a Czech seller, built in Turkey, it is also tall, but not as wide as the Givi.  I will see if that brings back the side buffeting or not for me.  I do like a short screen for bushwacking and mud bogging, but I love the tall screen for the highway miles.  Plan is to incorporate a pouch into my tail bag to hold the spare short screen when I need to take both.

[CaptainBackfire]

Ok, 90% is not bad but 100 would be nice. Let us know how it works out. It really would be nice to hear from someone who has totally nailed it

It would be nice to have a section on this forum that keeps a list of products and peoples success with them. Out of the gate I feel I need some lever protection and some engine and radiator protection. Barkbusters and doubletake mirrors seems like the first logical step but it would be nice to know what fits specifically to the T7.

[Osprio]

This is from another post of mine on the forum:

From an older GS, cut, bend with heatgun, made new holes and here it is. Nowhere near as big as it looks in the photo and no wind or noise whatsoever with lip up. Warmer or rainy days lip down, plenty of wind but no buffeting, just clean air.

 

[CaptainBackfire]

Powerbronzebsport screen and rally seat on. Tested and failed. I feel I need the screen to be 50mm lower. Tried without the screen but standing up is still far better. Turbulence from the crossbar i suspect.  Now what...

[CaptainBackfire]

On 6/26/2020 at 3:42 PM, Osprio said:

This is from another post of mine on the forum:

From an older GS, cut, bend with heatgun, made new holes and here it is. Nowhere near as big as it looks in the photo and no wind or noise whatsoever with lip up. Warmer or rainy days lip down, plenty of wind but no buffeting, just clean air.

 

Very nice. What material?  How does the wind noice compare to standing up?

 

[CaptainBackfire]

Removed The crossbar and lowered The screen. Better when i reach 90km/hour The turbulence is anoying. Removed The screen complegely with NO crossbar. Yet better but still not as good as standing up. It seems The hole front of the bike can not act like a naked bike. Im starting to close in on the point of selling The bike. The idea was to have a bike with weather protection so this might be an exercise in futility anyways. Bortom line... I need a screen that lowers The wind noice to a level less or equal to The wind noice when standing up. Has anyone achieved this? Please let me know. Geting ready to cut my losses 

Edited July 7, 2020 by CaptainBackfire

[MGG]

With the normal windshield I was not able to hear my thoughts at 120km/h so I ordered a new Givi windshield, installed it ... and noise is gone ... but there is new turbulence that shakes the top of my helmet at  anything above 100km/h ... Touratech Aventuro ... Now I am waiting on a spoiler to fix this problem ... Not sure there is a magic solution other than an electric windshield that acts like a sail and increases fuel consumption by 150%.

I also had to remove my handguards since the Givi screen is larger as well so at maximum turn position the handguards hit the screen ... I guess a handlebar riser is required to move everything backwards.

 

 

Edited July 7, 2020 by MGG
Added picture

[al700]

Anyone installed the T7rally.com screen adjuster? I am worried there may be wind coming through the gap created when you lift the screen.

[Colddog]

37 minutes ago, MGG said:

With the normal windshield I was not able to hear my thoughts at 120km/h so I ordered a new Givi windshield, installed it ... and noise is gone ... but there is new turbulence that shakes the top of my helmet at  anything above 100km/h ... Touratech Aventuro ... Now I am waiting on a spoiler to fix this problem ... Not sure there is a magic solution other than an electric windshield that acts like a sail and increases fuel consumption by 150%.

I also had to remove my handguards since the Givi screen is larger as well so at maximum turn position the handguards hit the screen ... I guess a handlebar riser is required to move everything backwards.

 

 

I have the same findings, waiting for the T7 rally adjuster to try to fine tune this screen.  The turbulence I'm feeling/seeing is seemingly like a form of cavitation where the low pressure area behind the screen seems to induce a popping type of buffeting.  With the screen adjuster, I'm hoping that letting a little more air under the screen may lower the differential pressure enough that the popping will be minimised. 

On another tangent, i have tried out a tall screen from online seller inpreda.  It is the best yet besides the massive barn door I built.  I hope to get the Givi sorted out because I payed so much for it that it seems like it is now family!  Lol!

 

 

[CaptainBackfire]

Ordered the givi too now. Chose the taker one. Also ordered thev t7rally screen adjuster. None of witch seems to be sent yet. I am betting the last chips on this. Or the bike goes. @MGG to be clear is the sound level you experience less equal or louder with the givi then when standing up?

[MGG]

3 hours ago, CaptainBackfire said:

Ordered the givi too now. Chose the taker one. Also ordered thev t7rally screen adjuster. None of witch seems to be sent yet. I am betting the last chips on this. Or the bike goes. @MGG to be clear is the sound level you experience less equal or louder with the givi then when standing up?

The sound level is quite acceptable sitting down and it depends on speed but I would say it's a bit higher than standing but that may be the top of my helmet issue. The vibration resonance may be because of the helmet visor of my Touratech Aventuro.

 I will try a ride without it and report back.

 

Edit:

... did a test and I can confirm the sound level is lower sitting down all the way up to 100-110km/h ... after that the turbulence is taking over and standing up is better. I did remove the visor on my helmet so the actual sound/air pressure vibration is almost gone. I am glad I bought it and even as is I can live with it.

I think that a spoiler or slight mod to the angle or height might fix the vibration issue completely....  

I just wish I had clean air instead of the protected air behind the windshield. 

Edited July 11, 2020 by MGG
typos + update ...

[Combo]

On 6/22/2020 at 12:04 AM, REDHORSECA said:

Can someone help me out and measure the side wind screens for me please. I don't have my T7 yet.

 

I want to vinyl wrap the side wind screens and I want to make sure I order a piece big enough.

 

Thanks, much appreciated!.

A=10 7/8" B=11 1/4"