Why Rory McIlroy's Iron Switch Isn’t as Radical as It Sounds

Rory McIlroy sent shockwaves through the golf world this week after pulling his longtime TaylorMade RORS Proto blades from the bag and replacing them with a custom set of P7CBs. The explanation was simple: he wanted more forgiveness. That single word lit the internet on fire.

The prevailing take was immediate and loud—if Rory McIlroy needs forgiveness, nobody should be playing blades. But that reaction misses an important point: Rory didn’t abandon blades. He slid a half-step sideways within the smallest margin modern iron design allows.

Rory’s new P7CBs are still very much in the players irons category. When looking at them on the spectrum of irons in today's game, they are still closer to being a blade than something like a hollow body P770 or Callaway Apex. In today’s modern world of club design, there are way more categories of irons than in the past. Let's consider how we got here and what this all means in the scope of the modern game.

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Where It Started

Before Karsten Solheim developed the first set of cavity back irons in the early 1960s, the only options golfers had were single-piece forged blade irons. This innovation was born after Karsten demonstrated with the Ping 1-A putter that, when weight was moved away from the middle and redistributed behind the heel and toe, it would resist twisting on off-center hits thanks to increased MOI (moment of inertia). This discovery led him to try this in irons, and in 1961, the Ping 69 Ballnamic forged irons were brought to life.

Image Credit: Ping

This brings us to the late 1960s as Karsten continued his innovation with the PING K 1 Irons—one of the first irons to be produced from a cast 17-4 stainless steel. After that, in 1978, the Ping Eye irons were introduced. The “Eye” name came from a cavity in the back of the club that resembled the shape of an eye, which helped improve feel and once again increased forgiveness.

Four years later, the famous PING Eye 2 irons hit the market, forever changing the way manufacturers thought about irons.

Where We Are Today

Thanks to improvements in technology and design, only a small section of modern touring pros still elect to play blades, and even of those, many still play some sort of combo setup with more forgiving, longer irons. However, of those using blades or small cavity irons, they are still playing clubs a long way from a player's distance or game improvement irons.

Technology and manufacturing improvement have gotten to the point where many smaller-profile irons are hitting game improvement forgiveness levels with irons like Cobra’s 3DP Tour, and Mizuno’s M15.

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That evolution in iron design is important to understand, because what helps the average golfer often creates a different set of problems for elite players.

This is another reason why, even though most pros are switching to irons with “more forgiveness,” you will never see them take the jump into players distance or performance models. When they hit a club, they want it to go exactly that distance—and not a yard further. Hitting a driver 10 yards longer is sick. Hitting a 7-iron 10 yards longer is an automatic bogey.

This is all to say that Rory switching to his new set of irons is certainly a story, but it isn’t as far of a jump as some are making it out to be. Modern blades and CBs are much closer to each other than you'd think.

Blades Versus Cavity Backs

Most blades and CBs are manufacturered through the process of forging where the metal is shaped from a larger piece of steel rod. There are cases where other materials are used in the process to help redistribute mass, but overall the shaping porcess remains the same.

Where they begin to vary is how mass is distributed within the clubhead. Karsten’s original discovery still holds true today, where you see more mass around the toe and heel sections of most cavity backs to help stabilize the face on off-center strikes.

You will also see more mass lower in the head to help with adding height to the golf ball. This is one reason you see many players who still like blades implement a combo set. Once you get to clubs like 4 and 5 irons that are much lower in loft, it is tougher to get a muscle-back up to an ideal peak height. This is where that extra mass comes into play.

Above: Wilson's recently released Staff Irons offered in Blade (left) and CB (Right) Models. | Image Credit: Ryan Barath

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However, even though they have more mass, the goal behind both of these irons is very similar. Elite players want to know that when they strike a ball in the middle of the club face, the ball is going to fly a very specific distance. One of them just helps a tad more when striking it off-center. The difference is truly marginal, but when the margins are as razor thin as they are on TOUR, you take what you can get.

So this bears the question, why are some pros still playing blades?

When Blades Get Put Into Play

You hear all the time that blades are more workable than their more forgiving counterparts. While the best players in the world are able to curve the ball in any direction with any build, where I find truth in this statement is the ability to manipulate height.

I mentioned that golfers who don’t hit it high enough would switch to a cavity back in a longer iron. But, if you are someone who doesn’t struggle with this, blades are going to be easier to manipulate your ball into different “windows.” You hear tour pros talk about this all the time—wanting to make sure they flight their ball through a very specific section of the air.

This is why you will never see Tiger play anything other than a blade. He is notorious for using different clubs to hit different shots because it is what that shot demands. In any given round of golf, you may have 3-5 shots a round where you give it your standard “stock” swing. Outside of those you are going to need to make something happen, and with all things being equal, a blade will make it easier to accomplish this.

However, the main reason I think you see guys still gaming blades is a simple one: it’s what they grew up using.

When you look at players that still game blades—Adam Scott, Tiger, Max Homa, Scottie, and Tommy Fleetwood to name a few—they haven’t played anything other than blades. When you spend so much time working with a specific profile, your entire game can be thrown off if you make a switch.

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Sure, the data in fittings never lie, and will usually lead you to a correct decision in what to put in the bag. However, comfort is a data point that no TrackMan or GCQuad are able to measure. When millions of dollars are on the line coming down the stretch, you are going to want to lean on something you have a history with, not something that a computer says is theoretically better.

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