Date:         Wed, 12 Aug 1998 08:23:40 -0700
Reply-To:     Michael Harrnacker <harrnack@YAHOO.COM>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Michael Harrnacker <harrnack@YAHOO.COM>
Subject:      Re: What Bentley says Re: Speedo calibration (longish)
Comments: To: Vanagon@VANAGON.COM
Content-Type: text/plain; charset=us-ascii

two ways to forget about all this speedometer calibration stuff and/or
not worry about getting speeding tickets...

1.  Live in Montana where the speed limit is determined largely by
your personal safety level, not the number on the speedo.

or

2.  Drive a Vanagon, where typical highway speed IS top speed.  Only
can get a ticket in town, or in a few eastern states.  Any state with
a speed limit of 65 or more, forget about it.

Mike Harrnacker (covered both ways)
89 Weekender "Nameles"
Missoula, MT



DAPrescott@AOL.COM wrote:
>
> In a message dated 98-08-12 05:43:30 EDT, you write:
>
> > If you look in the Bently manual it states (somewhere) that the
speedo is
> >  purposly set to read about 5% below actual speed in order to meet
us DOT
> > laws.  It also explains the number stamped below the VDO.
>
> Todd et al:
>
> Bentley page 90.30 reads as follows:
>
> As of  May of 1983 the existing regulations (FMVSS 127) concerning
vehicle
> speed indication were cancelled by the Department of Transportation
(DOT).
> Starting May 1983, the only requirement is that the vehicle's
speedometer
> indicate a higher speed than is actually being driven.
> Speedometers having European calibration specifications were
installed in
> vehicles for models years 1984 through 1985 (until December 1984
production).
> These speedometer heads have a basic tolerance of (+) 6.2 miles per
hour with
> an additional (+) 5% of the actual speed driven.
>
> For example
>
>      Actual Speed          50 miles per hour
>      + Basic Tolerance   6.2
>      + 5% of Actual        2.5
> ____________________________________
> Max. indicated speed:  58.7 miles per hour
>
> Speedometers with the former FMVSS 127 calibration are installed
starting with
> December 1984 production. These speedometer heads have a tolerance
of (+) 3
> miles per hour.
>
> For example
>       Actual Speed         50 miles per hour
>      + Basic Tolerance   3
> ___________________________________
> Max. indicated speed   53 miles per hour
>
> Bentley also note on the same page (under the Odometer heading) that:
>
> The number printed on the speedometer face plate beneath the word
MPH shows
> the number of revolutions required by the speedometer cable
mulitplied by 100
> to travel a distance of 1/100th of a mile (52 feet, 9.5 inches)
>
> >  The question is if using the number to calibrate still means that
the speeo
> >  will read 5% slow?
>
> The speedo will, it appears, read as much as 6.2 MPH slow PLUS
another 5%
> slow, whatever you do.  This explains why on our last camping trip
we were
> going 75 MPH (indicated) and getting passed by just about everybody!
> I calculate an actual speed of as little as 62 MPH.  BTW, the speed
limit was
> 65, in case you wondered.
>
> The number (805 on mine) appears to give actual distance travelled,
reassuring
> us that the odometer is reasonably accurate.  Bentley says (-) 1% to
(+)
> 3.75%.  I don't think it bears on speed at all.
>
> Doug
>

==
Mike Harrnacker
89 Vanagon GL Weekender
91 Golf
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