That error is very common in the early Vanagons. To a point it is
intentional to slow you down. The odometer also over reads by ~3-4%. Your
tires turn at about 830 revolutions per mile. Your speedometer is marked 805
so that is the first error source. The speed over read is an attempt to make
you drive slower both for safety and economy. If you do plan to regularly
drive that fast get a cylinder head temperature gauge installed and use that
as a guide to slow down. Those engines don't freeze up or boil over, they
just melt.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Karl Ploessl
Sent: Monday, May 06, 2013 4:29 PM
To: vanagon@GERRY.VANAGON.COM
Subject: speedometer accuracy

so I finally got a GPS in my van. And what do I notice?
Speedometer says 60 mph and GPS says 45 mph! At 70 (speedometer) the GPS
says 62!
I am running Michelin Agilis 61 in size 185/14 C and it is a Westy 81
aircooled. And it is in Delaware to satisfy Scott.
The question I have: does this discrepancy also affect the odometer?

------
Karl
1981 Westy "Jenny"
2000 VW Jetta GLS VR6
Wilmington, DE