Mayf and List
I too thought there would not be any difference due to the calculation
method but because of the mathematical rules applied there can be a change
to the second and third decimals of speed. Probably not significant to
some but it clearly was to the governing body. They made the change in
January 1978 and made all records prior to that date "absolute" and
"therefore cannot be broken".
The 'new method' provides the average mean speed of two consecutive runs.
Times are required to be recorded to three decimal place of a second. (The
average of two times may then create four decimal places). Speeds are
finally stated at three decimal places (although this may be two when a
zero is the third decimal).
Whilst the FIM work in kph, I did the maths of averaging the times and then
calculating speed for a mile - in mph of course (I took two times slightly
above and below 12.800 seconds myself but do if you wish try others). Then
I did the calculation of the two run speeds from each time. Each mph will
be to as many decimals as your calculator or computer has character spaces
and should not be rounded or corrected. Then these speeds are averaged at
which point you take the figure at three decimal places. The difference
between the two methods for my figures was 0.005 mph.
(At 20 to 21 seconds the difference was 0.06 mph).
Try this some winter evening when its too cold in the garage and tell me if
you find the same.
Whatever the result the FIM changed its complete records lists in 1978.
Malcolm Pittwood, Derby, England
|