Awhile back someone pointed out that the Vanagon speedometer has a three digit
number inscribed on the face indicating the factory calibration.  This number
is the wheel revolutions per mile at which the speedometer reads accurately.

I checked Reinhardt ('82 Westy Diesel) and found 820 on the speedometer.  I
checked the Tire Rack website and found the Yoko 356's 185/14C's do 808
rev/mile.  I think this means my speedometer would read LOWER than my actual
speed if I run these tires.  Is that right?

Then I checked my newly acquired '82 GL Diesel and found 805 on the
speedometer.  I was surprised to find such a different calibration number
between the two vehicles.  With this vehicle, I would expect the speedometer to
read HIGHER (insignificant?) than actual speed with Yoko's.

Neither of these vehicles have Yoko's, or are on the road (yet).  I just wanted
check my understanding of the relationship between the calibration number and
the tires.  Anybody have a different perspective on this?

Maynard Southard  OvO '79
'82 Westy Diesel "Reinhardt"
'93 EV GL "Klinger"
'00 Golf GLS TDI "WooHoo"
'84 Jetta GL TD "Donor"
'82 Vanagon GL Diesel {as-yet unnamed}