

| Subject: | Re: speedo/odo error confusion |
| From: | mike miller |
| Date: | Wed, 24 Oct 2001 22:57:08 -0700 |
heard this is true in Germany. don't know about Canada or the US. > From: David Marshall <vanagon@VOLKSWAGEN.ORG> > Reply-To: David Marshall <vanagon@VOLKSWAGEN.ORG> > Date: Wed, 24 Oct 2001 22:31:17 -0700 > To: vanagon@GERRY.VANAGON.COM > Subject: Re: speedo/odo error confusion > > It is all big brother... the government doesn't want speeders, so they make > the car manufacturers install speedometers that read high on purpose. Hence > you can do 70 in a 65 zone and "get away with it" as you are really doing 65 > or 66 MPH. > > The best way to measure speed is with a GPS - very accurate, both in the > speedometer and odometer departments. The speedometer part can easily be > corrected by adjusting the needle - pull it off and reposition it the amount > the error is at 65mph. The odometer will require a different cog at the > pickup. > > My Syncro with 205R14s installed was spot on speed wise and a little low > odometer wise (2%). > > David Marshall > > Fast Forward Automotive Inc. > 4356 Quesnel Hixon Road > Quesnel BC Canada V2J 6Z3 > mailto:info@fastforward.ca <mailto:info@fastforward.ca> > http://www.fastforward.ca <http://www.fastforward.ca> > Phone: (250) 992 7775 FAX: (250) 992 1160 > > . Vanagon Accessories and Engine Conversions > . Transporter, Unimog and Iltis Sales > . European Lighting for most Audi and Volkswagen models > > > > -----Original Message----- > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf > Of Richard A. Jones > Sent: October 24, 2001 3:48 PM > To: vanagon@GERRY.VANAGON.COM > 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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