I don’t know much about physics and aerodynamics and all that jazz, so I’m just curious how effective are the windshields on motorcycles? Was kinda wondering if they’re actually useful for redirecting the wind while riding, or if it’s more for safety from debris that could get thrown up off the road?
ETA: Thanks for the replies, and for entertaining my curiosity!
It’s for both. Not filling your clothes and visor with bug splats is really nice, as well as the wind that is thrown more around/over you, which also greatly reduces noise.
In higher speeds it will somewhat affect the fuel usage, but hard to say exactly how much. Not a significant amount I’d say, being able to adjust mine.
Personally, I’d say if you’re a touring/adventure biker like me, a windshield is really a good thing to have!
Did you do any tests regarding the fuel usage? I’d argue it’d be lower since drag is reduced. The human body isn’t exactly aerodynamic.
My windshield doesn’t change much, only how high it goes (to push air above my head). It seems to add a little bit on my calculated fuel usage in the dashboard when it’s extended and I have set the cruise control to higher speeds (90km/h+), but it’s not that significant. I’d wager a number between 3 - 5% increase. The windshield has a bigger surface against the wind than my body, so it makes sense (I have the bigger windshield variant installed).
This is not something I have tested rigorously, only what I recall from personal experience on a Tracer 9 GT.
It depends on the bike and the design of the windscreen. I would say that most are designed to shelter you from the wind first. There might be a slight amount of protection from sand and rocks getting kicked up but most motorcycle windscreens don’t provide the rider with full coverage so you might still get drilled in the helmet by a rock even though the aerodynamics are directing airflow above your helmet.
What I found interesting when I was a new rider is that most windscreens aren’t even designed to be looked through. The rider typically looks over the top of the windscreen. I have ridden some cruisers with giant windscreens that are designed for looking through and they’re very annoying because as soon as a bug splatters on the windscreen there’s no way to clean it without pulling over to bust out a rag and some furniture polish.
I’d say the main benefit of a windscreen is comfort. On the highway it can be very tiring to hold your upper body against the wind without one. It also helps prevent buffeting of the helmet and it reduces noise in the helmet quite a bit so you can hear traffic or your music more easily. The downside of the wind protection is that it reduces airflow at low speeds which sucks when it’s hot as balls outside and you’re sitting on top of a hot engine, catalytic converter, and exhaust. Some fancy bikes like my R1200GS have adjustable height windscreens so you can choose between protection from the wind and rider-cooling airflow.
It depends on your riding position and what kind of roads you’re riding on and at what speeds. If you’re planning on doing long stretches of highway (yuk), you’ll want wind pressure relief pretty quickly. Smaller windshields tend to protect your torso and leave your head in the flow, some do almost nothing and some shield you so well you can ride in the rain without getting wet, while listening to music. From experience, the wind pressure gets to you after a while and your neck will hate you. You also want to remember that air resistance increases at the square of the speed, you’re quickly fighting a lot of pressure!
For riding long distances at highway speeds, I’d consider them essential. I remember when I was riding my naked cruiser for a 3 hour interstate highway ride just how physically exhausted I was at the end. The buffeting of the wind against your chest means you have to hang on tighter to handlebars. If you crouch down you get less wind, but now your body weight is shifted to your wrists and back, so up you go again to get buffeted by the wind. I stopped doing long distance interstate highway rides after that.
Massive difference for airflow.
Ride a small bike without one at highway speeds (50mph+) and the airflow hits you right in the chest.
