What has persuaded Cobra to launch One Length versions of the King F7 irons where the shafts are all the same length?
Simple. He's called Bryson DeChambeau and the former physics graduate, US Amateur Champion and now PGA Tour player has been playing single length irons since 2011 when he and his coach re-imagined the previously tried theory of single length irons.
Now that DeChambeau is signed to Cobra to play their clubs and wear Puma clothes, including a retro flat cap, the manufacturer has been quick to embrace the concept as I found out at their UK launch.
The One Length option is available with their King F7 and the King Forged Tour heads, but the same principle applies to both.
As it sounds, the concept is for all the irons to be the same length and in Cobra's case the One Length irons are 37.5 inches long with a 62.5° lie as standard, which is 7-iron set up for them.
The benefit is that you only need one set up for eight or nine clubs because the ball position and posture remain the same for each one as your current 7-iron, which should make the game easier to learn, practice and play.
It's not as simple as putting single length shafts in existing heads. In a Variable Length set the short irons have heavier heads than the long irons because the shafts are shorter. If you want to find out why this evolved this way then check out our Guide To Single Length Irons.
What Cobra did is make the heads of the short irons lighter, for example the 9-iron is 14g less than normal, and in a nice bit of symmetry, the 5 iron is 14g heavier than normal. Making the longer irons heavier also has the effect of lowering the CG and increasing the MOI to make it more forgiving.
You can see how the weighting differs by comparing where Cobra has placed the darker weights in the sole of the standard Forged Tour and the Forged Tour One Length.
Each One Length club should then hit it the same distance as a Variable length club because the slower club head speed from the shorter shaft in the long irons is offset by the increased weight of the head to deliver the same ball speed and hopefully the same distance. The opposite applies in the short irons, so I took out DeChambeau's King Forged One Length irons to see is this was true in practice.
If you read my review of the Variable Length Cobra King Forged Tour irons you will know that I am a big fan of these clubs. The look, feel and performance are everything you would expect from a forged better player iron. I am pleased to say that nothing changes this fact when the One Length shafts are inserted.
In the One Length short irons, the total distance for the 8-iron was almost exactly the same as the Variable Length and with all the shorter clubs I preferred the longer shaft.
It did not really feel much of a change and when you start hitting less than full swing pitches and chips I found that it felt easier. This is mainly due to the fact that it is more of an arms swing than usual so if you are a little jumpy with those half shots then the One Length concept is something you should really try out.
Even with the specialist One Length wedges, you just grip them at the full length around the greens and in the bunkers and they play just as a normal length would.
As I went up the set I started to see a slight difference in the total yardages between the One length and the Variable length clubs, but in the 6-iron the carry was again almost the same.
In the 4-iron there was more of a difference for me and depending on your swing speed, you might find that the 5-iron in the King Forged One Length is your limit as the shorter shaft just may not generate enough speed for the 20° loft, hence why the set stops at a 4-iron.
You can either move onto your hybrids or swap in the King F7 One Length 4-iron which has a higher launch built into larger, hollow cavity back head. The King F7 has the edge in terms of ease of use between the two iron models and for better players, I would suggest going down this route.
However the key thing is that if I was to switch, the distance gaps between each club in the One Length set were consistent and Cobra has done plenty of player testing to back this up.
What took a while was getting my head around playing the 4-iron from towards the middle of my stance with a shaft that is 2 inches shorter. Looking at the flag in the distance with your eyes vertically closer to the ground took a while to trust, but if you do, it will deliver.
Playing the short irons felt no different to me, but other players I have talked to found the long irons easy to adjust to and the short irons harder, so it may depend on something like what side of the bed you get out of as to how you find them.
The other DeChambeau influence is in the grip size as he is also a proponent of thicker grips because then you do not have to hold it as tight and therefore should gain power.
Having recently moved to a larger grip myself, I was pleased to see the One Length irons come with the Lamkin Crossline ACE Blue grip in a diameter equivalent to 4 layers of tape, which is almost a tour standard.
That may sound like a lot, but trust me it will work for you as I usually take a medium glove and it feels fine to me. Bryson has more than double this amount of tape under his grips so he is an even bigger believer.
The Cobra King Forged One Length irons come with the KBS FLT shaft that complements the heads well with its lighter feel.
However the best bit about the One Length set is that they are the same specs and the same price as the standard Variable Length set, which is great to see as sometimes new concepts cost more.
Both the King F7 and Forged Tour heads are very good, especially the latter, and that is what gives Cobra's One Length irons the edge over other single length models.
DeChambeau and Cobra think that this could be a game changer now that manufacturing technology has made creating One Length irons easier than before. It could be a slow burner, but anyone who struggles for accuracy with their irons, has an iffy short game or just wants to simplify things should definitely try them out.
Testing the King Forged One Length with another scratch golfer and an amateur international, we all looked at each other and said "I could do this", so it all really depends on your approach. For me, not having to think about varying my stance to suit the club was one less thing to think about and I could see how this would lead to an increase in consistency.
Cobra will be running plenty of trial days in the coming year so make sure you get along and see if the One Length theory can work for you. It's simple to learn, easy to use and above all it's fun and you can't say better than that.