What was the fastest speed of a pitch ever recorded by a pitcher in MLB? Who was it? I think it was either Nolan Ryan or Randy Johnson but I’m not sure.
“The Fastest recorded Pitch was thrown by Lynn Nolan Ryan (then of the California Angles) (b. 31 Jan 1947). It was measured at 162.3 km/h (100.9mph) on 20 August 1974 at Anaheim Stadium, California, USA.”
http://www.hillshawks.com.au/BackOffice/BodyDocs/Records.htm
http://baseball-almanac.com/rb_guin.shtml
The Guiness BoWR still adheres to this record in spite of the fact that lots of folks swear up and down that Randy Johnson has exceeded that. I haven’t found a concrete figure for Randy yet.
And then there was the famous Steve Dalkowski, who purportedly had a 110 mph fastball, and the arm-control of a fifteen-year old kid with a stack of Playboys. He once put an umpire in the hospital for three days.
http://www.sportingnews.com/archives/sports2000/players/175838.html
And let’s not forget Eddie Feigner, “The King.” He’ll be happy to tell you that he had a 110 mph fastball.
Note: yes, I do know that Steve never made it to the majors and The King is a softball exhibitionist. Just don’t let me get started on cricket…
Before his elbow started bothering him this year, Astro’s relief pitcher, Billy Wagner, regularly hit 100 mph with his heater. If he heals up properly, look for him to break good ol’ Nolan’s record.
(So as to prevent people from lecturing me, I will let it be known that I do realize that it is more difficult for a starting pitcher (such as Nolan Ryan) to throw this fast than it is for a relief pitcher (such as Billy Wagner).)
Just thinking about it, wouldn’t it be a kick in the pants for someone to break that record, and have the batter hit a homer off that pitch? Heh. 
You might get two records out of that one.
Ahhh… sure 'nuff. I hadn’t thought of that.
Measuring pitch speeds is a pretty flexible system; radar guns often give wildly differing reads on pitch speed. Several pitchers have exceeded 100 MPH but the measurements aren’t necessarily trustowrthy. Rob Dibble of the Reds was measured as high as 103 in the early 90’s, and may well have been the fastest ever. Billy Koch, now of the Blue Jays, has hit 100 a few times.
The fastest pitch ever hit for a home run, incidentally, was probably George Brett’s famous home run off Goose Gossage in the 1980 American League championship; Gossage’s pitch was 98 MPH, if memory serves, and Brett tanked it into the third deck of Yankee Stadium.
And on the subject of Steve Dalkowski, the guy was, incidentally, mentally retarded. His IQ was tested at Earl Weaver’s request when Weaver managed Dalkowski in the minors, and came out at about 58. Weaver concluded that the reason Dalkowski couldn’t pitch was because everyone and their dog was trying to give this amazing kid advice, and Dalkowski was confused and tried to do everything all at once. Weaver had Dalkowski do nothing but throw fastballs - and he pitched extremely well. Once Weaver wasn’t managing anymore he (Dalkowski) stopped pitching well, and eventually blew his arm out.
Ryan’s record is usually acknowledged as the fastest as it was measured under controlled conditions. Ryan probably threw faster than that in game situations, but I don’t think you can get a reliable measurement during a game if you’re just using a hand-held radar gun.
Bob Feller and Walter Johnson probably threw as hard as Ryan and Randy Johnson, but there weren’t very accurate ways to measure their velocity.
There is a different philosophy of pitching today as Walter Johnson and Feller didn’t have to throw 95+ mph fastballs all game long, but just in important situations. Ryan was someone who would throw 95+ mph fastballs all game long.
What about Koufax? As with Feller and Johnson, there probably was no accurate way to measure his heater. But it’s a fact that he had to take something off his fastball in order to gain control. So even his fastest pitch in his best seasons may not have been the fastest he was capable of.
From The Physics of Baseball by Robert K. Adair:[list]Fastballs lose about 8 mph on the trip from pitcher to plate, so you have to throw it 108 to make it cross the plate at 100.
Besides those pitchers already mentioned, others who are believed to have come close to the 100 mph mark are Smokey Joe Wood and Lefty Grove in the white leagues and Satchel Paige and Slim Jones in the Negro leagues.
Speeds of pitches were measured as early as 1914 with a ballistic pendulum.
What, softball doesn’t count?
Peace,
mangeorge
Softball is a different ball delivered in a different way, as is cricket. It’s like comparing apples and oranges.
Well, tangerines and oranges maybe. 
Peace,
mangeorge
I think it’s more like oranges and grapefruits if you go by the size of the two different balls.
Last season or the season before, Detroit Tigers youngster Matt Anderson hit 103 mph on a radar gun. He’d hit 100-101 a few times prior to that as well. So maybe it was a radar gun glitch; maybe not.
(They’ve since changed Anderson’s delivery in order for him to better control his pitches, and now he gets “only” in the 95-97 mph range.)
Obviously hard to say about the pre-radar gun era pitchers. I’ve heard Walter Johnson probably brought near-record heat.
Didn’t another Astros pitcher, J.R. Richard, used to exceed 100?
Anyway, I’d always heard the fastest pitch attributed to Nolan. But I’ve gotta believe that’s one record that some of these young phenoms coming up will eventually break, if they haven’t already.