Extra or regular duty -- which flies faster/further and why?

[corbind]

Extra or regular duty -- which flies faster/further and why? Please state your reason at length and if it is theoretical or from several tests. I always buy Wilson US Open Extra Duty but bought a can of Regular duty by mistake. Regular duty has less fuzz.

[minitraveller]

I always find the regular duty balls to fly more easily because they feel lighter. The extra duty balls to me seem harder and it's easier to hit a 'heavy' ball with them. Nothing theoretical, just my opinion. My guess is that it has to do with the amount of fuzz on the different types, as you noted.

[mikeler]

As you already noticed, regular duty has less fuzz on them. Less fuzz = less resistance to air making them fly through the air faster. It also makes them easier on your arm. For me, using regular duty balls on a hard court is not a big deal, but if you use extra duty balls on a clay court, they just becomes rocks as the extra fuzz just loves mating with clay particles.

[corbind]

Other opinions?

[Overheadsmash]

Regular Duty. Less fuzz, espcially important on clay (I play on Har-tru). Mikeler is 100% right.

Penn ATP regular duty are my faves.

[SystemicAnomaly]

The difference in air drag is the most significant factor. Fact, not opinion. Regular duty balls have less felt than XD, hence less air drag (friction). Note that a 120 mph serve will typically slow down to 90 mph just prior its the bounce -- this is a significant reduction in speed to to air drag. I'm certain that a noticeable/significant difference would be seen in the pre-bounce speed of a RD ball compared to an XD ball.

The bounce itself will also reduce the speed of the ball. However, I would not expect a RD ball to be significantly different from an XD ball in this respect -- unless the internal ball pressure and/or the rubber parameters of the 2 types of balls are different. After the ball bounce, there would be some further slowing of the ball due to air drag.

Some have speculated that and RD ball might be lighter than an XD ball. There may be a very slight difference, if any. According to the rules of tennis, the rebound height, diameter and the weight of an ITF/USTA-approved tournament ball must fall within a fairly narrow range. The allowed weight range for an approved ball is 1.975-2.095 ounces.

While the weight of a RD ball might be (slightly) lighter than an XD ball, it is the difference in air drag that is the most significant factor in the speed of the ball.
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