datsun-roadsters
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Re: Fixing a Speedometer - Possible?

To: "Nathaniel Leeds" <nmleeds@mindspring.com>
Subject: Re: Fixing a Speedometer - Possible?
From: "John F Sandhoff" <sandhoff@csus.edu>
Date: Mon, 28 Aug 2006 11:30:08 -0700
> Once I finally calmed down I noticed that the speedometer was still running
> about 130% fast...

What size tires are you running? If you've swapped to a low profile
remember that your speedo will now be off (but probably not by
as much as you're seeing). Original 14" Roadster tires from the factory
were around a series 78. That's a pretty tall sidewall and a significantly
larger circumference than today's low profile offerings.

To see if the calibration is off, and assuming your odometer is working
(most of them aren't any more - cheap gears), measure out (using a
known-accurate car, or GPS, or roadside mileage markers) exactly
one mile (or 5 or 10...) then drive that in the Roadster and see what
your odo says. If the odo agrees, then your tire size/tranny drive gear/
speedo head are all in calibration. But if they're off, figure out the
percentage and I bet it'll be about 130% high...

-- John
     John F Sandhoff   sandhoff@csus.edu   Sacramento, CA




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