Design advances in woods have everybody talking. From larger clubheads to the use of exotic materials, today's woods are not only designed better, they're also manufactured better. Add to these changes the advances made in shaft technology, and you have well-crafted metal woods engineered specifically to help you chop strokes off your golf handicap.



But advances in iron design are helping players as well. Golfers don't talk as much about these advances as they do about those in woods, but they're just as significant for improving your game. Iron advances, like those made in woods, help you hit the ball longer and straighter, and shave strokes from your golf handicap. Let's take a closer look as some of these design advances.

Perimeter Weighting and Investment Casting

The revolution began forty years ago when Karsten Solheim turned traditional iron design on its head by introducing the concepts of perimeter weighting and investment cast manufacturing. Since then the advances have continued apace.

Perimeter weighting (PW) creates a large sweet spot on the club. PW repositions the weight of the clubhead around the perimeter of the clubface instead of at its center. If a player always hit the ball dead center, he or she would want a small sweet spot and no perimeter weighting. That way the club would have as much physical mass directly behind the impact point as possible. However, if the player is off even a millimeter, his or her shot goes astray. By perimeter weighting golf clubs, manufacturers' create maximum forgiveness in the club.

Investment casting is another key advancement in iron production. Many manufacturers produce irons by pouring molten metal in a pre-shaped cast. Cast irons provide the user with less feel, but are less difficult to hit consistently, and are therefore better suite for players with high golf handicaps. Forged irons have a softer feel and are less forgiving to a user, but they cause the ball to turn more off line when mis-hit.

Thinner Designs

Solheim's advances were followed by the introduction of new materials, like scandium alloys, and of improved manufacturing techniques, like computer-milled faces, in iron design. These advances also took iron design and construction in new directions.

Club engineers were gaining a better understanding of how each characteristic of a clubhead, like moment of inertia (MOI) and center of gravity), impacts club performance, and were beginning to take advantage of this knowledge. Today's clubfaces, for example, are thinner than their predecessors. Thin design frees up more mass that designers can redistribute to lower the center of gravity (COG) or improve moment of inertia (MOI).

Re-positioning the COG, as I've explained in my golf tips, creates a more forgiving iron, with a larger sweet spot along the blade. Thus, a mis-hit with an iron whose COG has been re-distributed is more likely to stay on target than a similar shot with an iron whose COG has not been redistributed. Why? Because a redistributed iron twists less in a player's hand when the ball is mis-hit. The ball is also likely to travel farther on a mis-hit as well.

MOI is a property of physics that indicates the relative difference in how easy or difficult it will be to set any object in motion about a defined axis of rotation. The higher the MOI of an object, the more force will have to be applied to set that object in a rotational motion. Conversely, the lower the MOI, the less force needed to make the object rotate about an axis.

Shaft Lean and Swingweight

Shaft lean is another new design concept that has found its way into club design. Shaft lean is the angle at which the club must be delivered to the ball at impact to create optimal pressure. Keep in mind that a ball compresses when hit, which causes it to spring off the face at maximum velocity, which leads to maximum distance. A forward-leaning shaft at impact, particularly when hitting the short- and mid irons is critical to solid ball striking.

Swing weight is also a key iron design feature that affects performance. In non-technical terms, swingweight is a measure of how the weight of the club feels when it's swung. Why is it important? If your clubs do not match in swingweight, they may not all feel the same to you during your swing. That slight change in feel could affect your performance with those clubs.

Philosophy and Intent Remain Key

The introduction of concepts in club design, like swingweight and perimeter weighting, is not new in itself. Club manufacturers have always sought new ways to improve an iron's performance. What's new is their approach. They are now trying to think of ways to improve one area of the club while keeping the other areas consistent.

What's this mean for you? It means that you must decide which design ideas are worthwhile and which are just marketing hype. Next time you buy irons, don't just buy something that's on sale. Study the philosophy behind the model's design and construction and what the manufacturer is trying to achieve with the club. If you do that, you'll get your money's worth and you'll get a set of irons that will help you lower your golf handicap.

Copyright (c) 2007 Jack Moorehouse