Bogart
89
Master Eight Days - 3-Day Performance Results
I am measuring the 8-day performance of the M8D as well as two other long-reserve, manual wind watches: The Chopard Quattro and the Lange 1. The watches are primarily being kept in a horizontal resting position (face up), although I reserve the right to wear each of them for brief periods during the test. I know this destroys the purity of the test, but that's a price I'm willing to pay. The reference is a radio-controlled quartz desk clock.
The JLC uses two barrels to achieve an 8-day reserve and runs at 28,800 bph. The Chopard uses four barrels to achieve a 9.5-day reserve and also runs at 28,800 bph. The Lange uses two barrels for a 3-day reserve and runs at 21,600 bph.
It has been 72 hours, requiring a rewinding of the Lange 1, and this seems like a good time to report the results so far. The numbers below the cumulative results are daily variations (in seconds).
The JLC Master Eight Days has lost 15 seconds
-5
-5
-5
The Chopard Quattro has lost 5 seconds
-6
-6
+7
The Lange 1 has gained 6 seconds
-1
+6
+1
For reference, COSC requirements are: The rate of the watch must be within +6 seconds and -4 seconds per day, in addition the greatest deviation between the fastest and slowest rate must not exceed five seconds, and the average deviation must not exceed a maximum of two seconds per day. The Chopard has been certified by COSC for an 8-day run.
