Windshield noise

[deilenberger]

Don,

On your next ride, take your left hand and cover up the right wind tunnel. That effectively covers both with your elbow over the left tunnel. I would be very surprised if you didn't get a significant reduction in helmet noise. At least this a free and easy experiment compared to what you have been up to.

It wouldn't surprise me at all if that does effect a change in noise since I've done that sort of thing when researching the CalSci shield with Mark Lawrence. What we realized was it was the change in my head position caused by reaching forward and down that actually made the change happen. It's easier and a more effective test to simply move your hand around the bottom of your helmet and see if the noise changes. If you have a well sealed helmet (the Schuberth Concept-II gaskets the neck quite effectively) I don't think it will. If you have an open-face or open-bottom helmet, I think it will.

It's a complex situation - air coming from all directions, and the riders body/head position and shape change the air patterns... dunno if there is one answer (actually I'd bet money there isn't.. but that's me.. doubting-don.)

Noise isn't a real issue for me. I am deaf enough already, and always wear custom-fitted earplugs on the bike, so noise isn't a big annoyance for me. What bothers me riding is turbulence - head-shake, and that's what I'm trying to lessen or eliminate.

A report on the 20" Cee-Bailey mounted in the tilted-back touring bracket: It's warmer (which was good this AM - 42F when I started out for work), but it actually seems to cause a bit more turbulence in my helmet at speeds above 70MPH. Most I got up to last night was a few bursts to 80MPH (GPS, not BMW speed - BMW speed was ~90..) Turbulence wasn't awful, and if I ducked down about 1" it went away. That's despite the shield being 2" larger than the 18" one that worked really well as far as turbulence. It is much better than my memory of the same shield mounted in a non-modified mount, so this is a good thing. I rarely go over 70MPH for any length of time in winter, so it will make a suitable winter shield.

I also looked at the BMW touring mount last night. The one I'm using has a modified loop on the bottom where it fastens to the body. The same thing could be accomplished a whole lot easier by getting two longer screws, and some tubular spacers for under the bottom mount. The bottom mount screws into the bike at an angle that spacing it out would have the same effect as the modified/longer loop.. and it would require no welding/painting/etc and be very easily reversable if someone didn't like it. There is a very slight bend of the two upper mounting arms required so they line up nicely with the upper mounting holes - but again - easy to do, and easily reverseable if you hated it.

As usual - YMMV, NTTAWWT..

[GOTJ]

OK Don, plug the tunnels like I have and try it. Why are you so convinced it won't work? I ride with a Schuberth C2. I also tried the hand around the helmet. It doesn't prove anything about the source. I also tried the hand around the wind screen. The I tried the hand on the tunnel. Works for me anyway.

Bobby, I have to import my "rolled up stuff" from a far-away land. It was custom made for JUST the R12R. You don't want to know what I would have to charge for it. So you can do what Don says doesn't prove anything and use the hand test I suggested to him. If you find it DOES change the placement of your helmet so much that the movement is the cause of the noise reduction, then you may have to resort to me.

BTW, I'm riding with the BMW tall windshield with no buffeting. The seat is close to a standard I think but it started as a low seat and modified locally. I also use a pumped-up Airhawk. I'm 6'1" with a 32" pants inseam.

[dderrig]

GOTJ (Ghost of Tom Joad?) I believe there are 2 things we deal with on our R's, buffeting and noise (noise in the sense of the low pitch stuff that your ears just can't handle, regardless off ear plugs).

IMHO the noise thing is related to where your helmet is in relation to where the air comes onto your body/head. If your winshield directs it in just the wrong place on your helmet you will get that noise (it's very similar to the noise you get in your car when the widows are cracked just the wrong amount).

Buffeting or turbulance is the flow of the air, is it clean and steady or all jumbled up! I do believe after now having the Wudo fairing that buffeting/turbulance is greatly reduced. I believe you and others who think the air colliding from the tank etc. adds to this turbulance.

The key IMHO is blocking that turbulance and getting your helmet in the right position in relation to the airflow over the screen.

Dave

[deilenberger]

OK Don, plug the tunnels like I have and try it. Why are you so convinced it won't work?

I didn't say it won't work.. I said make sure what you're seeing is really the cause of the change. And moving your hand around also moves your head and upper body.

It might be completely different for those of us who have tankbags..

I ride with a Schuberth C2. I also tried the hand around the helmet. It doesn't prove anything about the source. I also tried the hand around the wind screen. The I tried the hand on the tunnel. Works for me anyway.

That's cool.. but as I said - noise isn't a big concern for me. I'm much more interested in zero turbulence.

Bobby, I have to import my "rolled up stuff" from a far-away land. It was custom made for JUST the R12R. You don't want to know what I would have to charge for it. So you can do what Don says doesn't prove anything

That IS NOT WHAT I SAID.

and use the hand test I suggested to him. If you find it DOES change the placement of your helmet so much that the movement is the cause of the noise reduction, then you may have to resort to me.

BTW, I'm riding with the BMW tall windshield with no buffeting. The seat is close to a standard I think but it started as a low seat and modified locally. I also use a pumped-up Airhawk. I'm 6'1" with a 32" pants inseam.

Which puts your head in a much different position than 5'7" low seat, short (27") inseam me. I suspect your head is in clear air using the BMW touring shield.. not the case when I used it. Wind cutoff fell right about mid faceshield. And I assume "no buffeting" means no turbulence.. so we're talking about two different things. I can imagine a scenerio where more noise = less buffeting (greater amount of air behind the screen relieving more vacuum, which moves the vortexes further from the shield.) We might well be at cross-purposes.

[Mollygrubber]

Phew! I didn't mean to start a fight! I was just excited with my own personal results... hope this will eventually turn into a positive outcome. Until then, ommmmmmmmm...

[GOTJ]

Don, just STUFF IT - the tunnels I mean. Then tell us that it has no effect for you. It's a factual situation, not opinion. It either works or not. It works for me using both the hand and "rolled up stuff" so I don't know what else to say. I even have been riding and removed the "rolled up stuff" for a time and then reinstalled it. It DOES make a difference in my case and I think it would in many others, even yours. I'm looking forward to your report on blocking the tunnels with something other than your hand.

Mollygrubber, have you tried my "fix"? I'm interested in others' results. If so, how 'bout some info on height, inseam, seat etc. If not, please provide the same. So much of members' experiences are heavily influenced by that data. Don and I are quite far apart in that respect so we would look for different windshield solutions. In any case, I believe blocking the wind tunnels might benefit a large number of members and it is cheap and easy to try.

[deilenberger]

George,

On the way to the dentist tonight, I tried blocking off the left hole with my left hand (right hand was busy for some reason) at about 60-65MPH. No real change in noise for me, but I was able to follow the airstream from the hole - the wind blast was pretty distinctive. It comes up out of the hole and heads over to the left of my left shoulder. Probably about 10-12" to the left of my shoulder.

Some of that may be due to the tank bag.. but whatever.. In my case I don't think blocking this off would or did have a significant effect on noise. The airstream did feel turbulent (not a smooth flow - a pulsing flow..) so it's possible it may cause some turbulence behind the shield.

I suspect the tank bag has a fairly major effect on deflecting it from hitting me (or my head/helmet).. If I find time I'll find some tubing insulation and try your stuffing it into the hole..

[Mollygrubber]

I'm a little bit pissed - not because of the subject at hand - but because we are renovating our office and this has left me with no time to mess around with this, and has meant I must take my car into work to carry tools/materials so I haven't ridden since Monday.

What I am doing tomorrow is riding without the offending plastic shield in place (4 screws and some gummy glue and it's gone). I think this will settle it one way or the other, for me anyway. I doubt it will be perfect, but If it works, I think I'll silicone the exposed wiring harnesses and leave it at that for the time being.

I looked at installing some kind of deflector alongside the headlight boss, but there just isn't much clearance against the tank at full lock. Too bad, because those headlight boss mounting screws looked like just the ticket. As Churchill said, "Never never never give up.".

To those of you talking about stuffing the 'channels', aren't you concerned about loss of turning lock? I'd be scared to try that...

Well this has turned into a lively debate for better or worse. If nothing else it's reinforced my appreciation for you all, it's been nothing but educational with no harsh words spoken.

Thanks folks, we'll keep pounding away on this till we get it fixed I guess!

Peter

[Mollygrubber]

What I am doing tomorrow is riding without the offending plastic shield in place (4 screws and some gummy glue and it's gone). I think this will settle it one way or the other, for me anyway. I doubt it will be perfect, but If it works, I think I'll silicone the exposed wiring harnesses and leave it at that for the time being.

Results after removal of shroud:

Riding with a tank bag - it was worse! Picked up a pretty high amplitude mid frequency buzz which actually made it hard to focus my eyes at 120kmh (75mph), so the shroud is going back on tonight. I guess it does serve some purpose.

Oh well, that would have been too simple.

[deilenberger]

Peter - this is the black plastic shield on the front of the tank? I could understand how having the channels under the tank open might increase noise.. think of a flute.. Good (and easily reverseable) experiment.

[GOTJ]

Don, Very interesting. Good to get your report. I will be installing a tank bag in the near future and report on what effect, if any, it has on this issue on my bike. It may be that the stuffing won't be needed with the tank bag. But, for those who don't use a tank bag, I still think the stuffing would be a big help.

Peter, the only time the forks hit the stuffing is when I'm rolling the bike around in the garage and even then it offers no resistance to the forks hitting the fork stops on the bike. It just compresses slightly and then, when the fork is rotated outward, expands back to it's original position. I think it would be very difficult for the forks to contact the stuffing while riding at any speed above that where you didn't have your feet out for security.

BTW, the channels are not "stuffed", only blocked by a single piece of pipe insulation stuffed under the triple clamp at the top. You can see that there are still some small gaps to be filled in but this is my first iteration. I had hoped this was a fully "mature" subject with many simple and effective solutions already implemented by other members. Then I would use the one I like best.

One person mentioned that Ducati put some deflectors on the lower triple clamp. Our bikes don't have that. Putting something on the bottom of the headlight housing to block the channels might work though. I'll look at that next.

[GOTJ]

Don, I had the pleasure of visiting your web site and looking at your bike with it's TANK BAG. Good grief! If I had understood what you had mounted, I would have understood many of your comments. My preference in tank bags runs much smaller, more like a quarter to a third of what you use. So of course, I envisioned my preferences on your bike. I'm not sure why you even need a windshield with that big of a bag.

[deilenberger]

George,

Can't see how you'd carry your air compressor with a smaller tankbag.. much less 3-4 pairs of gloves..

[Mollygrubber]

I tried George's pipe insulation trick, it does make an improvement.

The type I used has a peel-off sticker along one edge, which I stuck to the leading edge of the tank, then stuck another piece underneath giving a stepped result (picture will follow, I'm at work today). I have used two (well, four) smaller pieces rather than one long one, and I have to say it still looks ghastly, but not as ghastly as George's 'baseball bat'.

Compressibility is good, giving full-lock steering. How long I can stand to look at it (and answer smart-ass questions about it) is ongoing.

I sent an email to BMW Motorrad regarding this FYI. I figure it's worth mentioning, if it will eliminate this issue, however small, from the next iteration of this bike.

[GOTJ]

Peter,

Ghastly is as ghastly does. However, my newest idea is to determine whether it takes something as thick as that insulation tube to get relief. I'm thinking of that sticky-backed weatherstipping that is used to fill cracks in doors and windows. The thickest I have found in a brief search is 7/16" but maybe it could be doubled up and work. It also comes in black so it would be less obtrusive. It even might be effective when placed lower down thus even less ghastly. I know we'll find a way.

[azimuth551]

I have just put on a CaliSci 20" wind screen. I was torn between the Cee-Bailey 18" I chose the CaliSci due to the design of the two ports. They help counteract the effect of the wind swinging back around and into the rider. I previously had the BMW Touring shield, while I like the looks a lot better, it does not offer the protection. My main complaint is the wind noise, even with good earplugs in, the noise makes ridding all day unbearable at times. I had a chance to go on a quick trip with this new windshield and I am impressed. The wind noise has gone down by at least half of what it was. I could ride now without earplugs and even hear the big twin under me, more than before. BTW, I am 5'9" with a 32" inseam with the regular seat height and I am using an Arai Quantum helmet.
Now I read about the "airscoope" on the front of the tank. I put one hand over an opening at about 70mph and the wind noise totally stopped with the exception of the wind at the top of my helmet. I was astonished to witness this design flaw. While the tank looks really cool, why would they design this into it? We have got to come up with a solution for this one. I don't know what can be made because the forks use this area when locked to either side. Does anybody have any thoughts on this?

Brent

[AncientMariner]

All this talk about airflow problems is quite worrisome to someone whose R12 is supposed to be built in 7 weeks (this has got to be the longest Christmas Eve of my life).

I test rode an R12 with the Sport Windshield and was amazed at how much turbulence and wind noise I experienced. At the time, I was not concerned because I knew, or so I thought, that the remedy was the hardware from the BMW touring shield with a Cee Baily 18" windshield attached.

Now it seems that the design of the fuel tank channels airflow right up at the rider, adding to the chatter. Well, I wonder if trying to block that flow is the right idea. Wouldn't it be better to redirect it off to the sides or perhaps up over the rider's head.

A pair of PVC elbows mounted at the top of the channel and aimed to the side might succeeed in throwing this air wake overboard.

An even more elegant solution might be to mount the sport windshield to the top of the channel so that it can direct the airflow up and over the rider. If this works it would be a welcome relief.

Not only that, but it would help to utilize all the sport windshiels that are no doubt languishing in people's garages.

Since I won't actually have a bike to try this on for some time, perhaps one of you fellow tinkerers could try this out and let the rest of us know.

Thanks in advance,

Bruce

[Mollygrubber]

Peter,

Ghastly is as ghastly does. However, my newest idea is to determine whether it takes something as thick as that insulation tube to get relief. I'm thinking of that sticky-backed weatherstipping that is used to fill cracks in doors and windows. The thickest I have found in a brief search is 7/16" but maybe it could be doubled up and work. It also comes in black so it would be less obtrusive. It even might be effective when placed lower down thus even less ghastly. I know we'll find a way.

I have a feeling that more blockage is better than 'tuned' blockage, for those of us without a wind tunnel at least. The layered pipe insulation nearly fills the gaps, and helps a lot. The pieces of yarn idea is cool, and one I have not yet tried.

I too, however, am looking for something slightly more elegant.

I have recently been thinking of mounting some louvres (sp?) on the front of my tank bag. Too much lateral thinking?

[deilenberger]

BMW used to make a pair of accordian sort of boots for the K100RT series bike that were to seal off the fork-tube openings in the bottom of the fairing. Something like this might work if it could be fastened to the bottom of the R12R tank.

PN: 2 in http://www.realoem.com/bmw/showparts.do ... g=31&fg=10

FWIW - in riding mine yesterday I played around with blocking off the openings some more. My results were diametrically the opposite of what's being reported here. Noise went up when I blocked off the left opening.

I do have a shield that purposely is pushed out at the bottom to channel air up the inside of the shield (relieving the vacuum that forms behind a shield), and I do have a largish tank bag.. both may make a difference. I was careful to make certain I moved no part of my body except my left-hand/arm.. since moving my head down and a bit forward does reduce wind noise caused by the top vent in my helmet (easily proved by shutting the top vent.)

YMMV and so may your noise levels.. nothing about this is simple, and there are a LOT of variables (meaning what works for one person may not work at all for someone else.)

[dderrig]

What wind chanels?