The most widely quoted response is Nolan Ryan, whose fastball was "officially" clocked by the Guinness Book of World Records at 100.9 miles per hour in a game played on August 20, 1974, versus the Detroit Tigers. A record that's still included in the book.

Did Nolan Ryan throw 108 mph?

Facing Nolan Ryan's Fastball

The guy could even swing the bat a little, like when kicked off his Houston years by hitting a home run off Los Angeles Dodgers' Don Sutton in 1980. According to the baseball documentary “Fastball”, Nolan Ryan? s final fastball, which he threw at age 46, was clocked at 98 MPH.

How fast did Nolan Ryan change his pitch?

Ryan's pitch was measured at 10 feet in front of home plate. When the proper adjustments are made, his 100.9 mph fastball becomes closer to 108.5 mph. If you are keeping score, that is about 3.5 mph faster than Chapman's fastest pitch on record. All hail the Ryan Express!