For the minority
who are prepared to swallow the truth, an understanding of the five standards
applied to golf balls is essential:
Weight – The ball can’t be heavier than
1.62 ounces. A ball a little
heavier would probably travel a little longer.
Size – The ball can’t be smaller than
1.68 inches in diameter. A smaller
ball might be advantageous – especially when played into the wind. The test used in the USGA lab calls for
balls to be tested at 75 degrees Fahrenheit after preparation in an
incubator. It’s such a sensitive
test that a five-degree drop in temperature can make the difference between pass
and fail because the ball contracts as it cools.
Velocity – The standard is expressed as 250 feet per second, with a 2%
tolerance, on the USGA apparatus, which features a metal flywheel as a
striker. The tolerance is a
scientific message saying that the device might fluctuate by as much as five
feet per second. Manufacturers are
confident that the performance is much better than the 2% tolerance
indicates. Many tend to build right
up to 255 feet per second – the standard plus the tolerance. Occasionally a brand will fall over the
line – ever so slightly - and is
stricken from the USGA list.
Symmetry – This test was introduced in 1983 following development of a
ball with an asymmetrical dimpling arrangement advertised as being a preventer
of extreme hooks and slices. A
symmetrical ball will do what it’s supposed to do – swerve off line when struck
improperly. It was on this
principle and to introduce the symmetry standard that the USGA
Distance – Introduced in 1976, this vital test is performed by robot –
the celebrated Iron Byron – which hits balls into a fairway outside the USGA
Research and Test Center. Iron
Byron used a conventional wooden driver with a loft angle of 11 degrees. At the instant of impact his club is
traveling 109 miles per hour, about the speed of a long-hitting touring
pro. A calibration ball is launched
at nine degrees. The clubhead is
laminated, not persimmon, because it simply doesn’t matter – in terms of
distance. About every 4,000 hits a
shaft snaps, which makes for a lively few seconds in the
Test Center as the clubhead ricochets off a wall or
For a ball to flunk the overall distance test, it would
have to travel 296.8 yeards – carry plus roll – under controlled
conditions. This is stated in the
specifications as a maximum of 280 yards plus a tolerance of 6%. When the Overall Distance Standard was
established in 1976 it was with the understanding that no ball then in existence
or in the pipeline of research would fail.
Thus, manufacturers were given a kind of innovative tolerance amounting
to an improvement on the order of 4%.
That gap has just about been closed.
In other words, the USGA now takes the position that
golf balls, when struck by a mechanical golfer designed to replicate what
happens in real life, are never to go more than a few yards longer than today’s
balls. It’s a shame the USGA
couldn’t have said that 30 or 50 years ago, but it’s useful to be able to say it
Note that there is a modifier in the USGA’s level of
confidence. It applies to
drivers. A variety of factors,
including dimpling configuration and weight distribution, causes balls to
perform differently at different launch angles.
*Adapted from 1987
U.S. Open Program.