5ktq speedometer error

[SJ]

>From: Ameer Antar <antar at comcast.net>
>Subject: Re: 5ktq speedometer error
>
>Larry, that's interesting. Mine has always been off. I guess they
eventually
>straightened it out, but us early type44 owners have to deal with it. Is
there
>any way to calibrate/adjust the reading on the speedo?
>-Ameer

To test the speedo accuracy, take a ride with a partner on an interstate
highway -preferably a flat section. And, preferably on a traffic slow day
and slow time of day - like Sunday morning at 7 AM.
Set cruise control for 60 mph.
Start stop watch, reg watch, whatever, when you pass a  XX.0 mile marker.
Maintain speed at exactly 60 if not using cruise control.
Make a note of the exact time as you pass each succsessive mile marker.

At 60 mph, you will go One mile in One minute, or 60 seconds. A 10 mile ride
will take 600 seconds exactly.

The longer the ride, the better your calibration will be.
A 10 mile ride(10 min) will give you a good calibration for your speedo.

mph=distance traveled/(#sec/60sec/min/60/min/hr)

per mile   Tot
time(sec)  time   dist   MPH
50          500     10    72.00
52          520     10    69.23
54          540     10    66.67
56          560     10    64.29
58          580     10    62.07
60          600     10    60.00
62          620     10    58.06
64          640     10    56.25
66          660     10    54.55
68          680     10    52.94
70          700     10    51.43

On the mechanical style speedos(88-5kq), you can adjust what the speedo
needle will show.

The needle works against spring tension.
The needle movement force is generated by a spinning magnet - a magnetic
field.
So, the magnetic field is working against the spring.

If the speedo indicates 55 when you are actually doing 60, you want to turn
the needle on its post clockwise - 55 position to 60 position.
If the speedo indicates 65, when you are actually doing 60, you want to turn
the needle on its post counter clockwise - 65 position to 60 position.

You can remove the needle off the pivot post, turn and hold post against its
spring, and reinstall the needle. In other words, you reinstall the needle
on a pre-tensioned post.

This is delicate work, and not meant for the ham-fisted.
I used a magnifier head set, good lights, and a set of small
tools(jewelers/watchmakers).

Or, just add a piece of tape on the speedo face . . ."55 = 60 actual"   .
.as a reminder.

Sidenote: most police departments will let you go if they clock you at 65 in
a 60 mph speed zone. Car speedos are not known for accuracy, so the police
make a 10% allowance for speedo error.
60 mph X 110% = 66 mph

Therefore: if you have calibrated your speedo, then you can "safely" drive
at 65 in a 60 mph zone without worrying about speeding tickets. BTDT, and
still doing it . .. for 10 years.
Actually, if you do 65 mph in a 60 mph zone, everyone will be passing you!
Well, almost everyone.

SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q




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