[ilovewatches]

Why bicolor? And why does the scale -going clockwise -start off with 60 to 50 then breaks off and begins at 250 at the 3 O clock mark. I thought tachy. Scales start with high numbers going clockwise and end up with 60 when you get back to the 12 o' clock mark?

 

[feca67]

The blue part of the scale is for converting time to speed for durations of less than 1 min, the red part for more than 1 min. E.g. 1 mile in 30sec = 120mph. 1 mile in 70sec = 51.4 mph.

 

[ilovewatches]

but...

Suppose you have 1 mile in under 15 sec then you can't compute it unless the assumption is that nothing short of a missile or rocket can go this fast.

 

[Chronomaster]

but...

Suppose you have 1 mile in under 15 sec then you can't compute it unless the assumption is that nothing short of a missile or rocket can go this fast.

ilovewatches- The bezel of the 6139-xxxx was never really intended for precise analytical mathematical splits smaller than one mile traveled in less than 15 seconds. One can obtain a "ballpark" measurement by taking the one mile traveled in 15 seconds at 250mph and counting backward in increments of mph into the red zone of the bezel. There are other watch models and brands better suited for figuring these formulas and results.