I re-read Tommie Smith’s autobiography Silent Gesture: The Autobiography of Tommie Smith (Sporting) and he mentions in Chapter 2 FOUR times that he held 11 World Records concurrently. The "11 World Records" are also mentioned on his Bio on the inside of the back cover.
But nowhere in the book does it list all the records. I am aware of the WRs from 200m and 400m, and perhaps the Imperial equivalent races in yards and meters, straight vs. turn 200 meters, relay races and indoor races.
I expected at the end of the book a detailed chronologically listing his accomplishments for a true autobiography, but it was nowhere to be found except for the clues on pages 150-151.
To quote those pages from Silent Gesture:
"Of the 11 simultaneous world records I once held, four were at the 200-meter or 220-yard distances, on the straightaway and the curve.
I also teamed up for some of the great relays of that time; teams I ran on held outdoor and indoor records in the 1,600 meter, the one-mile, the 880, and the 800 meters."
11 Concurrent World Records
Thanks to Derek Toliver, an Olympic Track and Field Historian, he clarified the world record performances.
In a span of one year from May 7, 1966 to May 20, 1967, Tommie Smith ran 5 races and received 10 World records.
In one race, two finish lines were used for the the 400m/440yd race, and the other 4 races had the Imperial distance bettering the Metric distance. Since the Imperial race in yards is greater than metric distance in meters, the WR is also credited to the metric distance.
Two finish lines are common for 1500m-Mile races and 30K en route to a Marathon road races, as long as they are ratified by the IAAF.
Imperial to metric conversions were used with Jesse Owens’ 6 World Records in 45 minutes, which were really 4 World Records or Equalled World Records plus the 2 equivalent credits.
For Tommie Smith, the 11th WR came from his 1968 Olympic Games 200 meters in Mexico City… a time of 19.83 seconds in altitude.
So in all fairness, he set records in 6 races with 4 coming from equivalent conversions and one from two finish lines.
Thus, 6 + 4 + 1 = 11 WR
It’s an incredible feat that has not been matched today.