My new single length irons are still on order and I hope to have them by the first week of February. In the meantime, I began to have second thoughts about ordering them with the stock True Temper F7 shafts. So wrote to Cobra to get some information about these shafts and why they were chosen for these irons. Cobra has an efficient and professional customer service department and my questions are almost always answered (via e-mail) within a day or two.
Cobra essentially answered my query by telling me that the True Temper F7 steel shafts (107 grams, mid flex, mid torque, parallel tip) were proprietary shafts that didn’t really match up with any standard shafts in the True Temper lineup. They went on to say that there was nothing unique about the shaft with regard to its use in single length irons (they use the same shaft in the normal length F7 irons). They do use a flighted KBS shaft (taper-tip) as the stock shaft in the more expensive forged version of the single length irons. A flighted shaft makes sense as it will be harder to get the longer irons airborne considering the shortened shaft length. Cobra suggested that the True Temper shafts were also designed to launch higher in the longer irons. Parallel shafts are all the same, right? I guess you could tip them differently to create a slightly softer (higher-launching?) tip in the longer irons. That’s beyond my club-making expertise. Maybe a reader (if I ever get any) can enlighten me.
In any case, I decided to change out the stock shafts with Nippon 950GH shafts in regular flex. I have used these shafts before and liked their feel and performance. Since the shaft chosen can be fitted in the conventional way (according to Cobra) and doesn’t really affect the single length club characteristics, I figured why not? They were a no-charge upgrade. So, at least for Cobras, the heads are where all the differences are with regard to the single length irons. As far as I know, I think that just means changing the weighting of heads to achieve consistent swing-weights with the single length clubs. I know Wishon uses different technology in the heads of the lower irons to create a faster face and make up for potential distance loss from shorter lengths and less hot faces in the short irons to have the opposite effect. I think Cobra has similar technology in their F7 irons, but I think it is the same technology whether you order single length or standard irons.
The reason for playing with the face speeds is, I assume, to create proper distance gapping between irons. So I sent the following question to Cobra. “Let’s assume a 100 yard sand wedge- what yardages would you predict for each of the irons down to the 5, given your design.” They answered as follows: The distance gap between your irons would be the same as a normal variable length set, only difference that we noticed in testing was towards your longer irons like the 4 and 5 you may lose about 2-3 yards since you arent swinging those clubs as fast as you would when they are normal length but thats where most players, not everyone, is replacing long irons with hybrids.
Losing distance in the longer irons makes sense, not only because of slower swing speeds associated with shorter shafts, but also because of smaller loft gaps in shorter irons which is the result of almost all manufacturers jacking up lofts in shorter irons to make you think you are hitting their clubs further. This would suggest that in single length irons, something needs to be done both to improve distance in the 4-6 irons and also to increase trajectory. I don’t really see that Cobra has done this in the F7 One irons and that would lead me to predict that I will have trouble getting height on my 5&6 irons and will hit them relatively shorter (in terms of distance gaps between irons). Maybe that’s why they didn’t actually answer my original question and just told me distance gaps would be the same as a “normal” set. As I mentioned earlier, the consistent 5 degree gaps from 7 iron to sand wedge in my set worry me a bit. Normal gapping (whatever normal means these days is usually around 4 degrees. A wider gap combined with a longer length (all irons are 7 iron length) suggest the distance gaps might be too wide in the short irons. We’ll see.