Fowlmead lap distances

I noticed the avarage speeds in the results are faster than what my speedo said, either my speedo is under-reading or the lap distance for the results calculation is longer than the actual distance.
As for the actual measurement, I'm not sure on that one.
For the 2 hour the results say 35.7mph but my speedo says 34.3mph avg speed, 2.07.58 time and 73.24 miles ridden. I stopped the speedo just after seeing the chequered flag.
Deviding distance by 35 laps gives me 2.09 miles/lap

Edited by LeeW - 11 June 2012 at 9:05pm

Gerard (the timing chap) said it was 3.1KM as well...

I can adjust the time if we agree on a distance. Fowlmead says 3.5km. Lee's calc gives 3.36km. Still off from 3.1! So does anyone have a better measurement. And as lee points out the racing line of a bike will be shorter than the inner/outer/middle measurement of a track.

KevinJ wrote: the racing line of a bike will be shorter than the inner/outer/middle measurement of a track.

However this makes a trivial difference to the lap length. Assuming a circular track (to make the maths easy) the difference between 3.1km and 3.5km is equivalent to an increase in radius of around 64m. In other words the track would have to be 64m wide for there to be 400m difference between riding round the inside and riding round the outside. A difference in racing line of 5m, which is just about plausible, only adds just over 30m to the lap length.

I recall this coming up in previous years and the conclusion was that the Fowlmead figure of 3.5km was the total amount of track, including the two cut-throughs.


Edited by Andrew S - 13 June 2012 at 1:26pm

So the differences (which are linear of course would be