Date:         Tue, 19 Feb 2002 14:38:24 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: right sized tires, wrong speed indication
Comments: To: Matthias Kuster <choreboy@CNMNETWORK.COM>
In-Reply-To:  <B897CF0A.1E89%choreboy@cnmnetwork.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 12:44 PM 2/19/2002, Matthias Kuster wrote:
>loaf is an animal, no doubt. My speedometer says 95 mph when I'm at 4100
>rpm, stock engine. Go figure. I let her have it, actually think maybe it was
>something VW did, so when people took it for a test drive, they would be
>convinced that Vanagons aren't such lame ducks. After all, they feel like
>they're going fast.

According To Bentley, a bad ground connection at the transmission can cause
a sneak current through the speedo spring that will overheat it and make
the gauge read high.  It's listed as an item to check if you have a high
speedo reading.

Model years '84 and '85 through end November 1984 have speedos with
tolerance of -0, +(6.2 mph +5% of actual speed).  At an actual 70 that
would give a maximum reading of 70 + 6.2 + 3.5 = 80.  This is the standard
European calibration, apparently.

Other years before and after have a tolerance of -0, +3 mph.  If you pull
your speedo out of the housing you can see the calibration limit marks on
the edge of the scale and tell which one you have.

Odometer has a tolerance of -1%, +3.75% of actual, as required by Federal
Trade Commission.  As of May 1983 the DOT requirement for speedometers is
only that they read high, but apparently customer demand forced VW to
reinstate the closer calibration part way through 1985 production.

However -- this is all based on 805 revs/mile, which is low for a
185-series tire; so in practice they all read a bit high with those tires
even if they're dead nuts on the calibration.

david


--
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"