The GCR 5.01 iron featuring Transitional Mass™ technology is a high performance cavity iron designed to be easy to use and to allow golfers to achieve more enjoyment from their game.

501 Iron

Transitional Mass™ technology is progressively biased lineal weight movement throughout the set to create a lower centre of gravity in long irons which makes it easier to get the ball airborne, and a higher centre of gravity in the short irons to produce a lower, more controlled ball flight. Transitional Mass™ weight distribution is also employed in the face thickness of each iron throughout the set that concentrates more mass in the exact centre of gravity in each iron for unmatched feel, feedback and forgiveness.

The 5.01 Irons begin with a clean and classic profile and are produced in heat treated 431 stainless steel to create a soft telegraphic feel at impact. What changes from a classic iron, and changes the shot making dramatically, is the positioning of weight (mass) in each iron head. While building in four way perimeter weighting to reduce the loss of distance caused by off centre hits, and optimised by each iron being 11% oversize, the real innovation is the mass in each iron transitioning vertically by 0.5mm per number, from the #3 iron right through to the sand iron.

But what benefit is this in simple terms? The centre of gravity on the #3 iron is just .42” from the level ground on which the 1.68” diameter golf ball is sitting. Now if the centre of gravity is focused on impact at the bottom 25% of the ball, where else can it go but up? That makes sense….. doesn’t it? The centre of gravity is then dynamically positioned slightly higher in each successive iron so that the focus moves from achieving distance through higher flight in the long irons, to turning off centre hits into acceptable results with the mid irons, and finally to controlling the trajectory of the short irons so that the ball doesn’t “balloon” in the wind. And while Transitional Mass™ controls trajectory, the moment of inertia, or twisting caused by off centre impact, is controlled by the flow design of the wide cavity and the density applied to the perimeter weighting maximises the shot dispersion pattern, meaning that direction will be more consistent. The combination of trajectory control and directional control leads to just one conclusion; every shot will achieve a better result which leads to lower scores. And isn’t that what we are all looking for?

In addition to the application of Transitional Mass™, the sole of each iron has been dramatically sculpted to achieve a number of benefits. When a 5.01 iron is placed in the address position, it automatically aligns itself square to the target line by way of the wide channel sole, which not only helps to hit straighter shots, but prevents digging at impact as it glides through the ball creating crisper contact, which means more ball control. In conjunction with the transitioning of mass throughout the set, the channel sole progressively narrows as the angle of impact changes with the shorter irons and higher lofts.

To ensure that each set of GCR 5.01 irons is a proper set, each entire set is built one at a time rather than making batches of individual irons. Technicians precisely match the weights of each head to each shaft, ferrule, and grip. Lightweight Transitional Mass™ steel or graphite shafts are not only perfectly calibrated for correct flex, but weight sorted for consistency across each set. These measures ensure that every iron in every set will have unrivalled consistency from the #3 iron to the Sand Iron.

5.01 Iron


The world class quality in GCR golf equipment is undeniable, and the result of Transitional Mass™ and channel sole technology in the new GCR 5.01 irons is unparalleled ease of achieving straighter shots with optimum trajectory, proving you can buy a better game. And get more enjoyment from the game.

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