Jeremy, I have a similar swing speed (Driver 92-95mph) and I am testing both regular and stiff (Diamana Blue LTD 60). I have always been in between a stiff and regular shaft. Through a lot of testing I have decided that I am still able to play Stiff shafts in my irons (XP 105 S300) and Stiff shafts in my Hybrids and Fairway Woods (Diamana Blue 70). I have both shafts (Stiff & Regular) for my 917 Driver and pretty much can go either way, but still leaning towards Stiff at 59 years old.

Hey Jeremy,
In my own experience I've found that the flex really never made much of a difference in my shot patterns, the weight of the shaft however has. So just a thought, maybe check the weight of the two different shafts as well. Also different club makers can effect a shot bias for sure (i.e. going from cally to titleist). The two heads could be setup completely different just in a "standard position". Anyway just food for thought. Saw your other post also, welcome to all threads!
Good luck!

I have had a similar results to what you are describing. I am now 46 and have a driver swing speed in the mid to upper 90's. I was fit this spring at my local shop for a completely new all Titleist setup from putter to driver and we ended up going with regular flex for everything except my driver. The results have been higher launch and straighter ball flight. It was a great move for me.

I'm mid 50's and made the switch to reg. Flex on my irons when I bought the 716's. My distance is similar but ball flight is much better and accuracy has improved since I am able to swing smoother. At the end of the day my joints feel better to where the softer flex absorbs some of the impact from ball and ground. I wish I had switched sooner.

Hey Jeremy,
I recently made the change from stiff to regular shafts ! My fitter suggested xp90's R-300 shafts, previously I was playing s-300's in my Macgregor blades. I purchased AP2-716 irons . After a few rounds under my belt I've noticed that my shots are ballooning & typically on the left side of the green . At this point I'm thinking that I should send the irons back to Titleist & reshaft the with the XP 105's or the XP 115's ? Not sure if I need to go back to stiff or not ? Has anyone had any similar experiences with these shafts ?
Thanks
Vince

It might not just be 'Flex'. It could be Flex and also bend profile and how different shaft companies have different guidelines for what each flex entails. For the sake of discussion, let's use Mitsubishi Diamana Whiteboard as an example. At one time, that in an X flex was very tough to load. Now, that same Whiteboard X flex might be a Stiff flex in a Graphite Design DI-8. Which might be an X or Tour X flex in Matrix Black Tie B8M.

Bend Profile is also a key factor. Having a strong transition in your swing may benefit from a stiffer butt section of the club. I don't know more about bend profiles, but that's just one example if I can recall correctly.

It could be perfect for your swing/timing. I hit my 7 iron 150 but I have stiff shafts in all my clubs from Driver to LW. My dispersion is tight throughout the set.

Its my impression that there is no standard for regular or stiff flex. What one shaft manufacturer calls stiff, another manufacturer could call regular. A quality club fitter can fit you to the proper shaft flex based on more accurate criteria. Don't be dependant on what the manufacturer prints on the shaft, its more marketing than science.

Note there is no industry standard for flex. So one can't expect stiff to be a universal feel. There are multiple variables in selecting the correct shaft so even if 2 golfers have the same head speed, they won't necessarily use the same shaft and flex. While my head speed is only about 85 mph, I have a high launch shaft in a stiff flex due to my transition. We started with the expected A-flex, but ended up at stiff to narrow dispersion. Empirically, most under 95 mph head speed would not do well with stiff. Most off the rack 9.5 drivers come in stiff that only fit a much smaller set of golfers that can use 9.5 drivers. Before paying upwards of 300 or 500 for a new FW or Driver, a good fitter will find my best shaft and I just need to accept the finding.

Interestingly, I am the opposite. Now over 60, I was fit for a 917D2 last month at a Titleist Thursdays. I had been playing regular shafts since my late 40s. At the fitting, it was determined that I should use a Diamana 60 in stiff flex. I didn't believe it. So, before purchasing a new 917D2, I tested a Diamana 60 stiff in my present 915D2 and sure enough, I am hitting the ball better now than I have in years. It's not always about swing speed. I only get through the ball at 93-96 mph or so. My fairways average about 67% just like with my regular shaft Aldila Rogue, but I am now getting better distance consistently with less spin (and getting in the heads of the guys in my regular group who always outdrove me!). Granted the Diamana is not particularly "stiff" as compared to some other stiff shafts, but it feels better to me than my regular flex Rogue. I will be purchasing my new 917D2 with the Diamana 60 in stiff flex, for sure.

Thanks everyone for your comments. It's nice to see people responding so quickly :)