Date: Wed, 24 Oct 2001 22:56:17 -0700
Reply-To: mike miller <mwmiller@CWNET.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: mike miller <mwmiller@CWNET.COM>
Subject: Re: spedo/odo error confusion
In-Reply-To: <20011024.234025.-567345.9.wilden1@juno.com>
Content-type: text/plain; charset="US-ASCII"
On interstates [and in California, other highways] road signs give the
distance between city halls, if any, and if not main post offices. As these
move rarely are the signs corrected. I don't know about maps being
corrected. I supposed that's up to the map companies.
The mile marks on highways, the ones supposed to be for speedometer checks,
are set with wheels much like, or identical to, the ones used to lay out
football fields, etc. Not accurate by surveying standards but plenty good
enough to check speedometers.
So you can trust the mile markers more than the mileage signs.
hope this helps someone.
Mike
also hope it's still correct, been a few years since I surveyed highways.
> From: Stan Wilder <wilden1@JUNO.COM>
> Reply-To: Stan Wilder <wilden1@JUNO.COM>
> Date: Wed, 24 Oct 2001 23:40:24 -0500
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: spedo/odo error confusion
>
> I'm using the 185 R 14--Michelin Agilis 61s.and a Spedo from an 85
> Vanagon (in an 83 Air-Cooled) with the black box from a 805 spedo and the
> 85 Vanagon Speedometer that has an 820 on the face.
> Too many numbers and getting confusing, but I'm getting a genuine 60
> miles an hour when I clock between highway mile markers at 60 second
> intervals.
> My trip meter is very close to the odometer miles and the published
> distances from one small town to the next. City to city is not an
> accurate measure against published distances.
> I resurrect some old 80-83 Westys as I find them and I always buy
> speedometers when I find them in wrecking yards. (I avoid those that have
> been wet.)
> Just from my experiences with speedometers I have found that the ones
> with just a little lag before they register 10 mph tend to be more
> accurate, must be because they are tighter in some way.
> I hope I've been able to add to the confusion.
>
> Stan Wilder
> 83 Air Cooled Westfalia
>
>
> On Wed, 24 Oct 2001 21:14:59 -0700 Todd Last <Rubatoguy@MINDSPRING.COM>
> writes:
>> The number "805" is the number of revolutions per mile that the
>> speedometer is
>> allegedly calibrated for at the factory.
>>
>> Todd
>> '88 Westy
>>
>> Joe Romas wrote:
>>
>>> I would venture that the wrong spedo has been put in your van
>> somewhere in
>>> the past. There's a little number on the bottom of the face. My 84
>> gl is
>>> "805" and it's a VDO brand. It has something to do with your
>> problems. Maybe
>>> others will know more about the numbers.
>>>
>>> Joe
>>>
>>> ----- Original Message -----
>>> From: "Richard A. Jones" <jones@COYOTE.COLORADO.EDU>
>>> To: <vanagon@GERRY.VANAGON.COM>
>>> Sent: Wednesday, October 24, 2001 6:47 PM
>>> Subject: speedo/odo error confusion
>>>
>>>> I just returned from a 3100 miles trip in El Jefe. Well,
>>>> 3100 according to its speedo, or rather its "odo"....
>>>>
>>>> I've know the speedo reads high from some time. Then
>>>> I watched the odometer between some mile posts and
>>>> decided it was high, too. I thought it was gear driven
>>>> and should be OK even if the speedo was off because of
>>>> the calibration of the spring. What do I know?
>>>>
>>>> I have the stock size tires--185 R 14--Michelin Agilis 61s.
>>>>
>>>> Then I decided to take advantage of I-70 which starts
>>>> from I-15 in Utah, with mileposts to the east.
>>>>
>>>> Here's what I recorded
>>>> my trip odo I-70 milepost
>>>> 77.8 0
>>>> 186.2 100
>>>> 292.0 200
>>>> 323.0 230 (Colorado state line)
>>>>
>>>> Converting to percentages:
>>>> 8.4%
>>>> 7.1%
>>>> 6.6%
>>>>
>>>> So if I drove an arbitrarily large number of miles my
>>>> odo error would be arbitrarily small? What's going on?
>>>> Why should the odo error not be roughly constant.
>>>>
>>>> The only variable I can think of is the day started
>>>> cool and warmed up as I drove, but only cool/warm,
>>>> not cold/hot.
>>>>
>>>> Can anyone explain this?
>>>>
>>>> [Trip report and photos to come later....]
>>>>
>>>> Richard A. Jones
>>>> Boulder, Colorado
>>>> '81 Vanagon Mr Bus
>>>> '87 Syncro Westy El Jefe
>>>>
>>
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