Bruce,
You can get a pretty good approximation from a gearing calculator.
Here's one:
http://www.angelfire.com/fl/procrastination/rear.html
Here's info on the speedo's innards:
http://home.comcast.net/~rhodes/speedo.html
You can 'calibrate' the speedo by repositioning the needle. It'll be
accurate only within a fairly narrow range; I usually shoot for accuracy
around 60mph.
I got a new cable from Moss a while ago that helped the bouncing needle
problem.
Bob
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
>
>
--
*******************************************************************
Bob Spidell San Jose, CA bspidell@comcast.net
*******************************************************************
_______________________________________________
Healeys@autox.team.net
Donate: http://www.team.net/donate.html
Suggested annual donation $12.75
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|