Date: Mon, 30 Sep 2002 02:22:03 +0100
Reply-To: Clive Smith <clive.harman-smith@NTLWORLD.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Clive Smith <clive.harman-smith@NTLWORLD.COM>
Subject: Re: Where to aim the headlights? SA grill.
Content-Type: text/plain; charset="iso-8859-1"
Now that sounds like the best advice to date - even main beam wants pointing
down a bit rather than being truly horizontal. Its the low lights in sports
cars etc that pisses me off, if you do the geometry you'll see what I mean.
Take the absurd case (as in calculus) and assume the headlight height is
zero, or on the ground. then there is NO way that main and dipped can be
reconciled, so being higher up than a saloon car is not the problem. I think
you're right (old and wise man), the arbiter is the cut-off point of the
dipped beam, and is anyway, the most defined of all. The other important
criteria is the off-side cut-off on dip, to avoid blinding oncoming traffic.
And what the hell is jacklighting? Ok, I've guessed, but I never cease to be
amazed at the US terms invented to describe just about everything about the
world - including tailgating at night. Is that possible anymore anyway, with
these modern and absurdly over-bright rear lights now being fitted to new
cars, especilaly those bl*** ridiculous circus lights fitted high-up above
tail gates - mad, crazy, how is one supposed to pick the subtelties of the
road ahead by looking through the car in front, or even around it when
you're being blinded at night by lights that are supposed to be for there
for safety. Huh! Modern auto engineers seem to be a bunch of immature
crack-heads out to impress without any real training, study and
comprehension of ergonomics - and thats what a sensible approach to rear
light design is - simple ergonomics. I think they should be banned, but what
has this got to do with headlights - think blue!
Clive
'88 Syncro Transporter
----- Original Message -----
From: "pensioner" <al_knoll@PACBELL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, September 29, 2002 6:01 PM
Subject: Re: Where to aim the headlights? SA grill.
> I've found that the key issue is where the top of the cutoff pattern of
the
> low beam is aimed.
>
> Ideally one would like not to "dazzle" the oncoming traffic yet still
retain
> the best possible illumination with low beams. Since the cutoff area is
> very precise, aiming the lights vertically using the image of the cutoff
on
> a distant wal has produced the best results for me in the past. Generally
a
> wal like that can be found after dark on the side of a Wal-Mart, aptly
> named. The wal is there during daylight hours but not as useful for
aiming
> headlights.
>
> I use a distance of ~100 feet or so and set the cutoffs about level or
> slightly low. Then I mark the wall with a piece of tape and take a test
> drive. Readjustment is often necessary so I have a reference from which
to
> work when I come back from the test drive. If no readjustment was needed,
> the tape is removed and we scurry away to jacklight some tarantulas.
>
> The relationship between cutoff and high beam is fixed for most
reflectors.
> If you aim one the other follows. Except for the Marchal Ampilux and the
> Cibie Bi Oscar of course. Here's where the jacklighting issues arise.
The
> center height of the headlights when mounted up high as in a vanagon is
not
> ideal for the fixed relationship between high and low. If you aim your
high
> beams for "best results", the lows will only be suitable for jacklighting
> toads at close range.
>
> If you aim the cutoffs properly, the high beams are aimed somewhat up,
not
> so up as to be useful for jacklighting owls but just the same above the
> ideal. So since most of my driving at night is done with the low beams, I
> aim those and let the high beam pattern illuminate the trees a little.
>
> Bosch/Hella 7" w 100/80 H4s.
>
> p
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