How do Adaptive or Cornering Headlights work?

Motorcycle companies since the ’80s have been coming up with patents and mumbling about adaptive headlights. BMW was the first to market over 10yrs ago offering an adaptive headlight on the K1600 GT. The headlight unit used a servo to rotate the normally fixed beam reflector around an axis, depending on the lean angle of the bike. All very trick in its day!

K1600 GT Headlight
K1600 GT Headlight

These days, all the bigger manufacturers like KTM, Ducati, Yamaha, and others are now offering adaptive headlights on higher-end models, fortunately, they are a little less complex and more reliable, except for BMW’s new system or Indian’s recent patent when it comes to complexity. More on this below 🙂

Why do you need adaptive headlights?

The main reason for the use of adaptive headlights is filling the blind spot when cornering at night. The fixed horizontal beam pattern in most headlight units creates a blind spot at the apex when you lean into a corner, it gets worse if you are counter-steering. If you have ever ridden at night in poorly illuminated areas or unlit roads, you know this can be an issue.

How do manufacturers solve the problem?

Different manufacturers have different approaches.

KTM, Yamaha, and Ducati use driving lamps on either side of the main headlight, that have multiple LEDs that illuminate based on the lean angle of the bike.

The latest BMW system is integrated into the main headlight and steers the dipped or low beam into the corner.

Indian motorcycles have a recent patent on a speed-sensitive adaptive headlight. The width of the beam path changes depending on the speed.

Let’s look at the current systems in a little more detail….

The lighting units contain a reflector and three LED’s that are activated separately based on the lean angle data received from the onboard IMU (Inertial Measurement Unit) on the motorcycle.

The KTM 1290 uses the following parameters for its adaptive headlights:
Lean angle of 10°+. 1st LED on the right-side lamp turns on.
Lean angle of 20°+. 2nd LED on the right-side lamp turns on.
Lean angle of 30°+. 3rd LED on the right-side lamp turns on.

The more you lean, the stronger the light output, and the more you illuminate the curve.

Video of the Yamaha system in action:

The BMW system uses a servo that moves in and out depending on the lean angle of the bike.

The servo meshes to a cog connected to the lamp. This cog rotates back and forth keeping the low beam lamp level with the horizon. The low beam lamp will stay level with the horizon up to a lean angle of 35°. In addition, the lamp can also pitch up and down 2° based on the acceleration, braking, or loading of the bike, pretty trick!

I’m not sure if I did a good job of explaining how the BMW system works, so hopefully, the photo and video below does the talking.

Servo (brown) with cog attached (orange)
Servo (brown) with cog attached (orange)

Video of the BMW system in action:

Indian Motorcycles:
This for me is the most interesting. It works much like the KTM system, with the added twist of increasing or decreasing the width of the beam path based on speed. At low speeds the beam has a wide path and at higher speeds narrower and more focused, throwing the beam over a longer distance.

Headlight Beam Patterns
Headlight Beam Patterns

At 90 kph, the beam will extend 3x longer than at 30 kph but will be 2x narrower.

If you really want to get into the Indian Motorcycle tech, the link to the full patent is here.

Can you fit aftermarket adaptive headlights?

Yes, you can, but they do not come cheap. Companies like JW Speaker make after-market adaptive headlights that can be fitted to just about any motorcycle, for around US$500-700 per unit. They work on the same principle as the KTM lights I described above. The only difference is they have an integrated lean angle sensor in the light housing, as opposed to using the bikes onboard IMU or lean angle sensor. Take a look at their website for more information.

I also found a Kickstarter campaign for a group called ALLight. Unfortunately, it appears to have stalled due to a lack of backing. The campaign page is worth a read if you are interested in this type of technology, the link is here.