During a fit of boredom at the office this morning, I think I have
derived the formula for figuring speed based upon final gearing & tire
diameter (LTD? - "loaded" tire diameter).

                   MPH/1000rpm = 2.975 x D/G          D = tire diameter
(inches)

G = final gear ratio

Hope this adds to everyone's worries about whether or not their speedos
are accurate.

BOB - WA4RRN
'85 GL - speedoless

ps-now, how do we know that our tachs are accurate???