BMW Motorrad testing S 1000 RR and rider in wind tunnel

Backriding may be allowed now, but one of the conditions is the installation of a barrier between the rider and his or her backrider. Motorcycle safety experts, engineers, manufacturers and the riding community have unanimous aired their opposition to it, calling it unsafe and an unnecessary burden to the already tough economic situation many are facing now due to the pandemic.

The government, however, maintains that the approved barrier shield design has undergone strict scrutiny from their select experts and is therefore safe for riding public use.

"Not aerodynamic"

Nonetheless, many continue to doubt the required barrier has undergone "thorough study" as the government claims they have. The one common issue many experts point out is how the barrier is detrimental to a motorcycle's aerodynamics. Many say the barrier can trap or catch air, particularly when the motorcycle is moving, making it harder to operate and causing it to consume more fuel.

BMW shows how they test a motorcycle’s aerodynamics using a wind tunnel image

What is aerodynamics?

So just what is aerodynamics, and why is it important to motorcycles?

To give our readers an idea of how aerodynamics matter to a motorcycle, BMW Motorrad showed us how they test their models for aerodynamics properties. This is extremely vital, particularly for the fastest, sportiest models and race bikes. This is because aerodynamic drag (air trapped in and around a bike) can actually slow it down. For race bikes, every kilometer per hour of extra speed and every millisecond of time shaved off a lap is vital. As such, they run their bikes through wind tunnel testing to make them as fast as possible.

Here, they are testing the BMW S 1000 RR and rider for the World Superbike Championship (WSBK).

“To simulate the flow conditions as realistically as possible, it is not enough to simply position the bike in the wind tunnel by itself. Out on the racetrack, there is also a rider on the bike, creating his own air resistance, even if his riding position has also been optimized aerodynamically. For that reason, the whole package of motorcycle and rider is used in the airflow, which is generated by the wind tunnel’s 2,600-hp electric motor and can reach speeds of up to 255 km/h. To make this possible, BMW Motorrad Motorsport has turned to an innovative method: 3D scanning,” says BMW Motorrad.

BMW shows how they test a motorcycle’s aerodynamics using a wind tunnel image

BMW Motorrad has also built a life-size model of their rider, Eugene Laverty, using 3D scanning. “He [Laverty] was trying to find the ideal sitting position on the RR and, while he was in that position, we took detailed measurements with a 3D scanner,” said BMW Motorrad Motorsport Director Marc Bongers.

Detailed measurements mean every individual glove finger, every contour of the helmet, every seam in the leather overalls, every crease that affects the aerodynamic drag and with it the airflow.

“Based on the data from the 3D scan, we created a plastic model made of two halves. It took about a week to get all the details right, however, our 3D Eugene was then ready for action,” Bongers added.

Since the rider double was completed, it has already undergone over 50 tests around the wind tunnel, providing valuable information to the BMW Motorrad racing team to further improve the S 1000 RR.

Why this kind of testing is important

Indeed, aerodynamics is usually more important for faster motorcycles. It's hardly ever an issue on slower, city-bound bikes. While we hardly see city scooters and underbones go through wind tunnel testing, the lessons learned from these faster bikes still influence the design of mass market models like scooters and underbones.

We're not asking for the government to run the backrider barrier through a wind tunnel test, but some consideration for its aerodynamic effects could have prevented a few accidents. And as an engineer proved, all it takes is an hour and a half to mock up a computer model and find out its effects.