How big is the sweet spot of your irons?

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In our biggest questions answered series, we decided to find out - just how big is the sweet spot of your irons? 

An iron's actual sweet spot, like any club, is no bigger than a pinhead. It's the point on the club where, when you hit a golf ball, the centre of gravity is moving directly towards the centre of the gravity of the golf ball.

Strike a ball from this point with a square club face and swing path and the resulting shot is straight with maximum distance. So why do we say hitting such an infinitely small dot is "sweet"? It's because when the two centre of gravities (club and ball) collide, you get maximum energy transfer, hence the term "sweet spot". Miss this pin prick of a point though, and the club head twists at impact, losing energy.

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Golf club designers and engineers know that by scooping weight out of the back of an iron and placing it around the edges, any twisting at impact can be greatly reduced. So while better player blades are wafer thin, game-improvement models have cavity backs, wide soles and thick top edges.This strategically positioned mass stabilises the head when shots are hit away from the centre of gravity, meaning less lost energy.

With that cleared up, how does the sweet spot size differ between a blade and a game- improvement iron? David Llewellyn, Director of R&D at Mizuno, reckons shots need to come from the area of a 5p piece on their new MP-18 MB irons, which are designed for top ball strikers. That area increases to the size of a 10p piece on the game-improving JPX900 Hot Metal.

In essence, game-improving tech delivers twice as much forgiveness. No matter what the design, though, shots lose about 10 per cent distance for a one-inch off-centre strike... for many of us that's 15 yards with a 7-iron!

NEXT: What's better - a playing lesson or a range lesson?