The SAE J581 Aux High Beam Thread
SAE J581 is the SAE standard for an auxiliary high beam driving light. This thread is to serve as a discussion point of distance auxiliary lighting.
This thread will be a work in progress for some time.
What is an SAE J581 Driving Light?
SAE J581 driving lights are a street legal auxiliary high beam pattern, meant to aid in the performance of your factory high beams and extend your distance visibility. Driving lights focus on maximizing distance projection while also providing a wider pattern than Spot, to broadly illuminate beyond the shoulders of the roadway ahead. SAE compliance calls for Driving lights to be white, selective yellow is not a legally compliant option. Driving lights are most useful at higher speeds to extend your visibility and reaction time. As they are a high beam pattern, they are only appropriate to use when you would run your factory high beams, aka not with vehicles ahead of you.
What about ‘Combo’ Driving Lights?
Many companies use misleading nomenclature and call combo pods/light bars a ‘driving light’. That is inaccurate and does not server the same purpose. Combo pods/bars have a short range flood/wide cornering optic paired with some distance optic. Actual Driving lights minimize short range foreground light, as that is more harmful than helpful at speed as foreground light reduces your distance vision. Combo lights are best suited for off road use, where short range foreground light may be helpful on the trail.
Several products are evaluated in this thread to demonstrate proper distance driving lights. However, while my SAE J583 fog thread has been comprehensive in product performance testing, this will not be, although I will continue to add products over time.
Lumens vs Candela
As not every possible light will be evaluated in this thread, it helps to have some knowledge on how to read lighting specs to have a baseline in comparing lights via spec. Many LED companies provide raw lumen values as a form of performance measurement, which is just a theoretical emitter output value and actually means very little as real lumen output will be far less. Some provide actual lumen values, which is the amount of measured light generated by the emitters, but again tells little on lamp performance. A highly efficient optical design can easily outperform a poor one, even if that poor optics lamp has more input lumens. What really matters is measured lamp performance, not theoretical or actual inputs to the system (the lamp) but what the actual outputs of the system are.
The best metric for understanding output performance is Candela. Candela tells you the beam intensity, and beam intensity is what directly translates to distance projection. Not to over-simplify things as there is certainly pattern area and beam type to consider, but in looking at what beam will project furthest for distance performance, you want to look at Candela.
Obviously there are many products not covered in this thread. Most notably Rigids SAE driving light bars and Diode Dynamics SAE Driving light bars which I would encourage you to also look at.
A distance light should be mounted higher up on a vehicle, optimally near headlight height, for best perspective and to minimize shadows. A driving light mounted down low, like the fog location is easily obstructed by changes in the roadway elevation. Mounting lights above the headlights and having them uncovered on the street is not legal in some states, despite the light being SAE compliant. Mounting in locations like the A-pillar or roof also have the possible complication of hood glare, which will reduce your eyes ability to see distance at night which is counter productive to the purpose of the driving light. The more focused the light, the less of an issue hood glare becomes, but the most ideal location is forward of the hood. Without an aftermarket bumper, auxiliary high beams can present unique mounting challenges. Behind the grill is a possible solution with the BAMF mount, though that does depend on your grill setup and some losses will be incurred.
Driving lights should be aimed directly forward, with no degrees of tilt down or to the sides. Since these lights project significant distance, a few degrees off can have a big impact, aiming can be more challenging than it would seem. JW Speaker has good aiming instructions for SAE J581 lights here.
When mounting SAE J581 lights in a compliant location, I would recommend wiring the lights to automatically come on with the high beams. This simplifies the operation for the driver so that when you pull the high beam lever you get both your factory and auxiliary high beams. Approaches for how to do this will vary by vehicle, but you’ll typically tap the high beam wire to trigger a relay to power the aux driving lights. This approach makes the setup perform as a seamless extension of your OEM lighting with no additional buttons or switches to fuss with.
Here are a few SAE J581 Aux High Beam Products
Diode Dynamics SS3 Sport Driving
Well known of the forum with interchangeable TIR optics and available 6000k or 4000k (with lens swap) color temp.
Pattern. Peak lux 2204 lux @ 18′.
Cibie/PIAA Driving Lights
These lights made are made by Valeo, a major OEM automotive lighting manufacture supplier and provider of Toyota’s OEM LED and halogen fogs. Valeo is the parent company to Cibie and owns a major stake in PIAA’s parent company, hence no surprise in these pods being sold under these brand names.
What is unique about the high beams is they use an OEM style sloped reflector, just like the OEM Tacoma LED high beams. These lights produce a focused hot spot with a very broad and naturally smooth wide spread pattern, like the OEM high beam.
I have the Cibies at drawing 17.9w shown below vs the SS3 Sports drawing 14.6w
SS3 Sport Driving vs Cibie/PIAA Driving
You can see the Sport just edges out the Cibie/Sport in peak output. I’d consider the patterns nearly equivalent in peak output intensity and instead focus on which provides the more useful pattern for your purpose.
Diode Dynamics SS3 Pro Driving
You’ll notice the pattern is noticeably larger and rounder than the SS3 Sports. While the Pros are higher in output, they also have less focus. But the output intensity in the Pro is still higher, which will translate to further distance projection.
In evaluating round lamp performance
KC Pro6 6” Driving vs Cebie Super Oscar 9” Driving
The 9″ Cebie model is huge! One of the interesting things here, is the KCs use LEDs pointed to the sides of the reflector assembly, whereas the Cibie’s use LEDs pointing up and down. KC uses the up and down arrangement in their G4 gravity lights (primarily fog), but all other gravity lights are to the sides.
Though both an SAE driving compliant beam, the beam patterns are quiet different. The Cibie have a very full and wide driving pattern carrying higher intensity light further toward the edges of the patterns and overall being wider than the KC while also producing less up light, whereas the KCs are more of a spot focus with lighter side proximity lighting.
Cibies draw 14.5w
KCs draw 22w.
Although larger reflectors are more efficient, the KCs also pull 50% more power.
Looking at peak intensity alone isn’t a great comparison in this case, because of the pattern difference. KCs spot-like pattern will project further, but I think the Cibie pattern is going to produce a more moderate/usable light pattern for most street driving scenarios, even though it will not project as far. So I wouldn’t say there is necessarily a clear winner here.
While on paper the KCs are a decisive winner on paper at 46% higher peak intensity, in practice it is a bit more complicated when factoring the pattern coverage, although the KC’s do it in a much smaller package.
Again this is to serve as a Aux High Beam discussion thread, not a comprehensive test source at this time.
The highest output intensity SAE J581 compliant driving lights I have found thus far are the excellent performing 5000k KC Pro6 Driving lights, and that is what I currently run on my truck.