Absolutely true.. I've often suggested to people who complain about noise and own a Schuberth helmet that the problem is noise induced by the windscreen. If they go for a ride screen-less they're usually amazed at how good a job the helmet makers (at least Schuberth) have done in a wind tunnel. I really enjoyed the clean air that the BMW sport screen produces (it provides almost no protection, so any turbulence it kicks up is down around my ample belly..)Ferenc wrote:Yestreday I must have been really frustrated as today I went through all of my screens in short comparative rides. Cee Bayley 23", than the BMW touring, than the BMW sport ... and finally something I have not tried earlier: no windscreen at all. Clearly, definitely and absolutely the best setup for minimizing noise, roar and buffeting is the setup without any screen at all! If I'd be sure to achieve with a taller 25" screen the same experience I'd try it yet once again irrespective if Cee Bailey or CalSci.
Problem is - bugs/rain - stuff like that. I don't like getting stung by yellow-jackets and hornets when riding (and I've had it happen WAY too many times on naked bikes), and I like some protection from rain hitting my chest (the Aerostich Roadcrafter is good - but it's even better with a bit of help.) Plus - hanging on at speed (70MPH or so - 120kpm?) becomes tiring.
So - I've ended up with a collection of windscreens (available for loan/trials to anyone who bothers to stop by my house.. I'm not shipping them..) Here is the collection, and my dimensions (which are important.. someone was collecting head-height from the bike, but I don't think he got enough data to be useful):
Me - 5'7" (on a tall day), 28" inseam (actually probably closer to 27"), I'm using a Sargent modified BMW "low seat". These are usually mounted in a BMW touring mount (unless noted) that has been modified (bottom mount extended) to tip the mount back about equal to a DonC 1" block. I normally ride with an RKA medium size tankbag.
- CeeBailey 16" Gen-I screen - my screen of choice for warm weather. Used with the modified mount - it provides nice clean air to my helmet, deflects bugs and provides some protection to my chest. The air starts out at about my chin level. There is some noise from the air - but no real turbulence at any speed I might go. A friend that tried this one and the new CB gen-II screen much preferred this one, he's about the same size as me, but is using the BMW "Comfort Seat" (which is ~ 3/4" taller then my low seat.) The visor on my Schuberth C2 will close itself (cracked open at the bottom - about 1/2") at around 60 MPH with this screen (the "City" position works fine - where one side of the visor - or both - are pulled forward.)
- CeeBailey 18" Gen-I screen - my all-round screen. It's been on since last fall. We had a mild winter, so I didn't feel any need to swap to my winter screen. This hits me at about mid-visor on my Schuberth. You can see a "bug-line" on my faceshield. Again - mounted in the modified touring mount - the air is clean, and no real turbulence.
- CeeBailey 20" Gen-I screen - my winter screen. I don't ride long distances at high speed when it gets below about 40F, but I'll do an occasional slab-blast. This provides the most protection of any of the CB Gen-I screens (obviously) - and used with the modified touring mount, turbulence isn't too bad, but it's more noticeable then the shorter ones. What I do find annoying (but not dangerously annoying) is the "sail effect" - where gusts of wind, and turbulence when passing trucks on the highway causes feedback into the bars.
- CeeBailey 25" Gen-II screen. It's on the shelf. IMHO - it's too tall for me. At the time that was the only height they had (that has since changed). I'm tempted to take a saw to it and cut it down a few inches to see how it does.
It has very little turbulence off the top edge - used with a stock mount or the modified mount. Above 65MPH it was a LOT of turbulence off the sides (where the wing like protrusions) stick out. The turbulence at 70-75 MPH (as fast as I felt comfortable with it) was enough to shake my shoulders. The turbulence hits me right about at shoulder height, and I tracked it down to air off the sides with moving my hand around. As it neared the side of the shield, my hand could feel the turbulence. Putting my hand in the air-stream off the top revealed clean air flowing off the top edge. I tried the screen with a stock touring mount, and my modified one - not a lot of difference in the turbulence from the sides, a bit of difference off the top (tipping it back helped this.)
As mentioned above my friend - who is roughly my size - and had borrowed my 16" Gen-I screen and tried it out on his unmodified touring mount on his 2011 R12R.. he thought it was great and was going to buy one.. until I asked him if he'd done a highway run with it. He hadn't - he did - and came back looking for a Gen-I to buy. Luckily someone here had a 16" Gen-I for sale, and he's a happy camper with it.
Another friend (John M - who is on this forum) borrowed it and liked it - but John is about 6' and I suspect he is a much better fit for the 25" height screen. I seem to recall he used with a DonC block (John?)
- CalSci 25" (from memory) screen. This was the beta-screen from Mark Lawrence for the R12R. I bought the first one he had offered, and thought it was so bad that I contacted him about sending it back. He immediately refunded my $$, and asked if I'd help him make it better.
So.. a number of his screens were shipped back and forth. The differences were primarily in width, and the size of the cutouts in the screen. Mark thought the turbulence from the screen could be made better by making the screen more upright, and making the holes in it larger. We tested that theory and found that making the holes bigger really didn't seem to help at all, and making the screen more upright made it worse. We tried making the holes much smaller - no real difference.
On my own, I used the spacers he provided to make it more upright to make it more tipped back, and it was immediately obvious that was the way to go (somewhat to Mark's surprise.)
Tipped back it was quite good for noise and turbulence, but it was simply too big for me (I like some air..) and it had too big a sail effect (pushed around by side-winds and truck turbulence.) So it's on the shelf. It's somewhat hacked up since Mark had me making the holes bigger, and I'm only so good a using a jigsaw on plastics.. I have not tried it on the modified mount that I now have, I suspect it would work just about as well as it did spaced out (about 3/4") from the bottom mounts to a stock mount. I could feel down-force on my front wheel when I got to speed with this one, enough that it was quite noticeable.
- MRA VarioScreen - This is the 2 part screen where the upper part sits in front of the lower part and is adjustable in height. There is a slot between the two halves that allows air to come up the inside of the upper part.
I was trying this with the BMW touring mount, which required me to drill some additional mounting holes in it, and slightly change the bend in the bottom part. There is a mount available for it (which I have and have never mounted) that allows the user to adjust the angle of the screen.
Using it with a stock BMW mount - the turbulence off the top edge was fairly awful. I never got around to trying it on my modified mount (guess I should some time..) Adjusting the height just moved the turbulence up and down. I tried blocking the slot between the two halves with some foam rubber - it had no effect at all, so to me that mean the slot wasn't doing anything useful.
It might work quite well if it was tipped back enough, I never had the ambition to install the MRA mount so I dunno. If someone wants to try it and wants to come by, you're welcome to give it a test. I don't remember noticing a big sail effect.
- BMW Touring Screen - I don't think I still have this one, but my impression of it was it directed turbulent air to my chest at about nipple height and was noisy. I never tried it on a modified mount. It didn't impress me a lot, and someone wanted to buy it - so it's gone.
- BMW Sport Screen - and mount. On the shelf. Gives quite nice clean air. Unfortunately - it provides almost no protection. If I only rode on sunny days and always below 70MPH this would be my screen of choice (but bees/wasps would still be a concern..)
That's my screen collection, and thoughts on all of them.
The conclusion I drew was you can reduce the turbulence coming off the top edge of any screen by tipping it back more (makes sense - less of a sheering action into the wind). Tipping back the screen with the turbulence off the side edges had no effect (which also makes sense since you're not changing the sheer angle.) Bigger isn't always better. And most important: There is no perfect windscreen for everyone.
