StolSpeed Vortex Generators on a Ducati Multistrada

With the Roar flaps, F. Fabbri screen, and Aztec spacers, the silence was golden. Unfortunately, that bubble of calm air wasn’t very wide. If I moved my head just a couple of inches left or right, my helmet would again be thrashed with turbulent air and my ears tortured by the deafening roar. And if I happened to pass a large SUV or truck, the bubble of calm air would mostly disappear.

To better understand where the turbulence was being generated, I covered my windscreen with homemade telltales, pieces of yarn taped down to show the direction of airflow, and rode at various speeds. I realized that a significant source of turbulence came from the screen pushing the air diagonally upward to the left and right at just the right angle to hit the bottom of my helmet when I leaned slightly to either side.

So I mounted StolSpeed vortex generators with 30 mm spacing at 15° angles to the streamlines indicated by the telltales. Wow, what an unbelievable difference!

I can now move my head almost a foot in either direction and stay in smooth air. Who knew a handful of tiny plastic vortex generators could widen the sweet spot so much?

Rider Feedback

“It took a few tries, but your vortex generators fixed the buffeting problem better than I thought possible. Once I got the locations right, the generators changed the buffet I was experiencing on the top of my helmet into a smooth laminar flow. I still get a pretty good wind blast across the top of the helmet, but it’s smooth rather than rough, almost like the difference between swimming in a current versus swimming in surf.”

“I should note that I also filed the windshield mounts to decrease the angle of attack of the windshield (I brought the top back about an inch). Changing the AOA alone didn’t fix the problem, but adding the VGs after adjusting the AOA made all the difference. I also discovered that dropping two sets of VGs an inch below the others significantly improved the airflow. I wouldn’t have predicted that, but I found it worked much better than a linear arrangement.”

— Noah, Texas