[Healeys] Incorrect Speedo Reading

[Al Malin]

A GPS (Garmin, Tom Tom, etc) will tell you what you want to know.

Al Malin
Tricarb





On May 27, 2010, at 11:17 PM, Bruce Griffin wrote:

> Gentlemen,
>
> This a very basic question, but I am hoping for some insight to see if
there
> is a common Healey reason for this.
>
> I know my speedo has been bouncing, so I want to replace the cable to see
if
> that helps.  My main question is how to estimate my speed based on my
> obviously incorrect speedo reading. I checked my speed with another car and
> knew it was off. Today, I passed a PD temp. speed camera that displays your
> speed. It indicated I was going 40mph, while my speedo showed my speed at
> 55mph. If I remember my engineering training from college, this is related
to
> the gear in the transmission and I should be able to adjust my speed by
using
> the fraction 40/55.  This assumes a portion for correction as opposed to a
> simple add 15mph because the gearing of the speedo drive gear is adjusted by
a
> percentage, not a fixed number.  Any advice appreciated.
>
> This is also a good math problem for my 11yo son.
>
> Regards,
> Bruce D. Griffin
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