There are approximately 70,000 tennis balls used each year at the U.S. Open.

But it’s actually a tale of two balls at the New York tournament.

It turns out, to the surprise of many close to the game, that men use different balls than women during their Grand Slam tilts.

According to the United States Tennis Association, the balls — manufactured by Wilson — are identical in every respect except for the yellow felt coating.

“Men and women use the same ball in terms of size, pressure and design,” according to a USTA statement. “The sole difference is that the men compete with an extra-duty felt ball while the women compete using a regular-duty felt ball.”

But this slight difference can have huge effects on speed and ball action, experts says.

Doubles specialist Bob Bryan uses both balls regularly at the Open, playing in men’s events and mixed doubles, where the women’s balls are also used.

Bryan told New York’s Newsday that he could coax an extra five or six miles an hour out of the less-felted ball, calling it “a real BB”

And York University tennis coach Michael Mitchell, who has studied the game for 25 years, says Bryan is likely right.

“Is there any truth to that? Absolutely,” says Mitchell, who was well aware of the fuzzy difference.

“They (the men) would probably hit the serve 175 miles per hour if they were using that (women’s) ball.”

Mitchell says the reason so many balls are used at top tournaments is to ensure the fuzz quotient remains constant, with worn balls tending to travel and spin much faster. He says, however, that the ball is suited to each game: with the regular, “hard-court felt” tending to slow down the men’s game and the lighter-felted balls speeding up the women’s.

Eugene Lapierre, director of the Rogers Cup tournament in Montreal, says it’s standard practice to use more felt when the men are in town and less with the women, who alternate between his city and Toronto each year.

Lapierre says men at Rogers use a ball manufactured by Penn when they’re in Montreal and Toronto because it’s part of an endorsement deal on their circuit. Women use a Wilson ball, he says, to get them ready for the U.S. Open, which typically follows hard on the heels of the Rogers event.

While Lapierre says his tournament simply employs the balls they’re told to use, it’s his understanding that the women’s version is made for clay courts to help speed up the game on that slower surface.

“I guess that’s the answer: They want the women’s game to be a little bit faster,” he says.

“But I’ve never (asked) why the women would use that different ball. We just take it for granted.”

That two balls were being used at the U.S. Open became news this past week when it was reported that retiring American star Andy Roddick was mistakenly handed one of the women’s balls — marked in red as opposed to the men’s black — during a match.

“See, the women use a different ball than we do, and I did what I normally do, get three or four balls and look for the one that looks the lightest to serve,” Roddick told Newsday.

“I have no idea where it came from,” he said, adding he resisted the temptation to serve the ball.

Not everyone agrees the ball with the less-felted pelt would move faster, however. Rick Janes, an expert on the sport’s technical aspects, says a lighter ball may actually slow down faster.

Loading... Loading... Loading... Loading... Loading... Loading...

Janes, a technical consultant for the Babolat tennis gear company and holder of 32 tennis equipment patents, said players who believe they’ll get more speed with the women’s ball “don’t live in a scientific world.

“He (Bryan) could be correct,” Janes said, “but that’s not necessarily the case. A lighter ball slows faster. Think of badminton. When they swing at the shuttlecock, it’s going really fast. But, within six feet, it literally stops, like a parachute effect.”

Janes said there was one certainty about the more densely felted ball: “if it hits you at 140 miles per hour (it) will hurt more.”