Daniel Stern's Headlamp Aim Page Revised

[Alaric Darconville]

http://www.danielsternlighting.com/tech/aim/aim.html has been revised!

People familiar with this link may have stopped clicking it by now, but it's worth clicking for a reread since it's been revamped. It's got a link to the VW instructions for using the Hella VAS 5107 Universal Beamsetter IV (quite the mouthful), which shows the results for various (VW) cars, but is a good reference for what YOUR vehicle aim should look like.

Also of note is that there are no longer different declination recommendations for ECE and VOL; all these lamps get the VOL declination recommendations. The ECE angles are much too low in Europe, and super extra WAY far too low in North America, meaning extremely curtailed low beam seeing distance.

For those unsure of where to find a shop with an aimer, it gives information on locating those dealerships or shops by way of querying the manufacturers.

Another thing that should go without saying (but I say it a bit, and it's said in this document)-- for many composite headlamps (and, of course, sealed beams) that the low and high beam offset is set within the lamp and is not independently adjustable-- always aim on low beam with such lamps. The high beams will then be correctly aimed unless you have a poorly-designed or just plain broken lamp. Only aim high beams separately if they can be independently adjusted without disturbing the low beam aim (generally, when they are a separate, and single-function, lamp).

Horizontal aim gets more than just a mention, with information on how to check and correct horizontal aim. Note that in the U.S., this function is typically locked out by law through the use of caps over the adjustment screws.

Fog lamps, which should be left OFF are easily aimed and the process is mentioned there.

 

[jaycee88]

Another thing that should go without saying (but I say it a bit, and it's said in this document)-- for many composite headlamps (and, of course, sealed beams) that the low and high beam offset is set within the lamp and is not independently adjustable-- always aim on low beam with such lamps.

Are motorcycles the exception to this? I seem to remember Virgil mentioning that motorcycle headlamps are to be aimed using the high beam, and J.W. Speaker's motorcycle headlamp aiming instructions also say to aim using high beam.

 

[jeffsf]

Also of note is that there are no longer different declination recommendations for ECE and VOL; all these lamps get the VOL declination recommendations.

Would you be able to summarize the current recommendations for VOL aim declination (or confirm that the DOT VOL numbers on Stern's page are current)?



My previous research has turned up, at least paying attention to details for private passenger vehicles with headlamps at around 28" above ground (with auto-leveling, in my case)

https://www.fhwa.dot.gov/publications/research/safety/humanfac/04148/aiming.cfm FHWA-HRT-04-148, December 2005

VOL systems have a vertical aiming plane 0.6° below the vertical reference point on the alignment board.

(0.6° ~ 1%)


​

Daniel Stern's response to the NHTSA light-glare queries states

aimed to US VOL specifications, with the cutoff set at 0.7%/0.4° down​

Edit: For completeness, his previously linked aiming page indicates 2.1" drop at 25' for headlamps up to 80 cm above ground, 0.7%, as does the linked VW document from that page, for US headlamps, which states, "Set the inclination % to 0.7% by turning the dial at the back of the box. The % indicated in the molding of the headlight is for Europe ONLY."​

https://www.hella.com/techworld/us/Technical/Automotive-lighting/Headlight-adjustment-835/ ("E-code" specific)

Marked on the light for recent vehicles (1990 and later)

Passenger cars (also combination motor vehicles) -- 1.2%

Motor vehicles with level-regulating suspension or automatic tilt compensation of the light beam -- 1%



​

https://www.jwspeaker.com/blog/how-to-aim-headlights-high-low-or-low-beam-headlights/

surprisingly doesn't indicate any drop suggested for the horizontal cutoff


​

https://www.truck-lite.com/content/news/quick-guide-aiming-headlights (not surprisingly for trucks, which usually have higher mounting positions)

suggests 2" at 25', or about 0.7% or 0.38°​

 

[Alaric Darconville]

Are motorcycles the exception to this? I seem to remember Virgil mentioning that motorcycle headlamps are to be aimed using the high beam, and J.W. Speaker's motorcycle headlamp aiming instructions also say to aim using high beam.

This may be because if the high beam aim is correct, ostensibly the inbuilt aim declension for the low beam will take care of the rest. Since a motorcycle headlighting system is only required to provide half the performance of an automobile headlighting system, it's crucial that high beam aim is correct as the motorcyclist will have a high reliance on it in high beam conditions.

Note that the low beam on a motorcycle headlamp is vertically symmetrical, also, so there's no upsweep to the right or left side regardless of what traffic directionality the motorcycle is sold or used in (remember, the bike leans this way and that on corners anyway, so controlling glare on a motorcycle is difficult). Thankfully, there's only one lamp producing glare, but it is a disadvantage for the motorcyclist to have just that one lamp.

 

[-Virgil-]

- FHWA got it wrong; they were citing the ECE spec, not the US VOL spec.
- Hella got it right in a nutshell/capsule-summary kind of way -- for Europe.
- Truck-Lite got it mostly right for the US.
- JW Speaker's aim advice is pretty scrambled up. I don't imagine anyone's giving them any pushback about it; this is America. Next time I'm President of JW Speaker, I'll be sure to fix it, LOL.

- Motorcycles seem to be absent from Stern's page. I don't remember if they were there before. Some motorcycle headlamps are aimed straight ahead on high beam; others with a straight-flat cutoff on low beam get aimed by positioning that cutoff.

UNECE low beams (European/rest-of-world lamps), for their type-approval testing, get aimed 1% down -- that is 0.573°, often rounded to "0.6°" in discussion. US VOL low beams, for their certification testing, get aimed 0.7% down (0.4°); VOR low beams get aimed straight ahead (cutoff at the horizon, 0% down).

There's nothing in US national laws or regulations (FMVSS 108 or anywhere else) that specifies how headlamps should be aimed on vehicles -- only how they should be aimed for their certification tests. It's just kind of assumed they'll be aimed that same way on the roads, and many (most/all?) optical headlamp aiming scopes, the US version of the Hella Beamsetter, for example, have a setting marked "VOL" (0.7% that is 0.4°) and a setting marked "VO - VOR" (0%), as opposed to the rest-of-world versions which have a range of percents on the dial.

That Hella remark about vehicles made after 1990 refers to the aim angle specification to be found on or near the headlamp of cars made after a certain date. That specification is determined according to a formula in UN Regulation 48 that accounts for mount height and the range of pitch motion allowed by the vehicle's suspension in response to specified weight loads, etc.

For lamps "in service" (on vehicles, on the road) the Europe/ROW prescribed settings start at 1% (0.573°) and they go down pretty fast with increasing lamp mount height and/or vehicle pitch range, down to 2.5% (1.44°). Alaric is right, all of these figures are much too low for adequate seeing distance no matter what country the car's being driven in.

As you can see here, the UK inspection protocol (other ROW countries are similar) allows low beams mounted up to 85 cm/33 inches above the road to be aimed between 0.5% down and 2% down. This allowable range means a low beam mounted at a fairly typical 60 cm above the road is permitted to give the driver anywhere between 30 and 120 meters (98 to 394 feet), an inappropriately huge range. In practice, most garages aim the lamps on the low side "to be safe" -- which it is not.

To look at this from another perspective, it means if you're aiming the lamps on a wall 25 feet away, the difference between the cutoff being 2" or 3" below horizontal is the difference between 60 or 86 meters (197 or 282 feet) seeing distance, a difference of 43 percent. From just one lousy inch of difference on the wall! You might begin to see why shining lights on a wall (while the car sits on ground that's sorta/kinda level) is only barely better than doing nothing.

The US specs for vehicles in service kind of don't matter; just about nobody ever checks. There are still a few states that do aim inspection, but they mostly just look for the lights that are high enough to spot planes or low enough to hit 3 feet in front of the car. For many years the SAE J599 lighting inspection code that most inspecting states used, and the few remaining inspecting states probably still use, okayed +/- 4 inches above/below horizontal and /left/right of center (at 25 feet -- this is an allowance of 0.764°) for all headlight beams. This is just about a pointless inspection, especially with today's lights -- a low beam aimed 4" up is, in effect, a high beam. Or it's practically not much better than a fog lamp if it's aimed 4" down.

So headlamp aim is a mess in the US and nobody cares, what else is new (except the IIHS, in their own way). Headlamp aim is more frequently checked in some other countries but they allow/encourage the lamps to be set too low...basically a different kind of mess.

Given all that, I'd call Stern's recommendations, at the very least, defensibly appropriate. And the careful (if wordy...like I'm one to talk!) explanations that go along with them probably encourage productive, helpful attention to getting the headlamps pointing where they should be.

 

[-Virgil-]

Note that the low beam on a motorcycle headlamp is vertically symmetrical, also, so there's no upsweep to the right or left side regardless of what traffic directionality the motorcycle is sold or used in

But also remember that car-type headlamps with asymmetrical low beams are legal on motorcycles all over the world. Many motorcycle headlamps do have symmetrical low beams, but others don't.

 

[Alaric Darconville]

But also remember that car-type headlamps with asymmetrical low beams are legal on motorcycles all over the world. Many motorcycle headlamps do have symmetrical low beams, but others don't.

I'd say the biggest problem is that once you set the static aim of the motorcycle headlamp (which moves with the forks and changes angles constantly due to leaning and such), that attempting to aim them almost seems like folly.

I nudged Daniel about it and he should have some updates for it in the next few days.

 

[Alaric Darconville]

Note: This thread will be unstickied on or before Wednesday, April 1.

 

[-Virgil-]

I'd say the biggest problem is that once you set the static aim of the motorcycle headlamp (which moves with the forks and changes angles constantly due to leaning and such), that attempting to aim them almost seems like folly.

That's why JW Speaker's adaptive motorcycle headlamps exist -- they work as claimed. The concept is a lot older; certain Japanese makers patented what amounted to gimballed headlamp mounts for motorcycles in the 1980s. I don't think any of them went into production.

I nudged Daniel about it and he should have some updates for it in the next few days.

Good deal; I'll keep hitting "Refresh" until my browser tells me to stop it

 

[Alaric Darconville]

Daniel Stern also reminded me that until recently, SAE J584 only provided for high beam aim (a throwback to the sealed-beam only days).
Another update is that there will be more (and better) aimed-beam diagrams-- no more MacPaint!

 

[Alaric Darconville]

And we have information on motorcycles. And better pictures!

 

[jaycee88]

Some motorcycle headlamps are aimed straight ahead on high beam; others with a straight-flat cutoff on low beam get aimed by positioning that cutoff.

Are there markings on the motorcycle headlamp lens to indicate which method of aim to use?

 

[-Virgil-]

Are there markings on the motorcycle headlamp lens to indicate which method of aim to use?

Unfortunately not; it's only in the latest revision of SAE J584, published this past February (or maybe the one before that; I'd need to dig), that a "VOM" marking has been added to indicate low beam aim by cutoff position. And since FMVSS 108 doesn't automatically or periodically get updated to refer to the latest SAE standards, there is no requirement for a "VOM" marking. Without getting too far off into the weeds on the subject, you're more likely to be able to do an accurate job of aiming by manipulating the low beam cutoff (if it exists) than by trying to set the high beam hot zone dead-ahead.