Club Head Speed Differential Question

I took my son (10, soon to be 11) to get fitted for new iron shafts today as he has clearly outgrown his Flynn shafts. I know his driver swing speed because I check it once a month or so when we are at the range. Last time I checked, which was a few weeks ago, he was around 75mph. So, imagine my surprise today when he was swinging his 6-iron around 69mph.

It took him about 20 swings or so to get up to that speed and he stayed there pretty much the entire time. After we had found the best shaft for his irons, I had him take his driver out just to see what his speed would be. After he warmed up, he was averaging around 78mph. At this point, he was about 100 swings in, so I thought maybe fatigue could be causing him to swing the driver more slowly than otherwise would be the case. But, I had him jump right back into his 6-iron and he was back up to 69mph on the first swing. So, I don't think fatigue played into the driver speed.

Is a 9mph differential between 6-iron and driver typical for a 10 year old? I have about a 17mph differential between my 6-iron and driver, so 9mph seems very close.

For what it’s worth, I don’t think there is any swing flaw causing the driver speed. The TrackMan optimizer showed his numbers were nearly perfect for both the 6-iron and driver. Smash with the 6-iron averaged 1.41 and got as high as 1.44, driver averaged 1.50.

Any advice or anecdotes would be greatly appreciated.

not to cause a debate but smash on a 6 iron for pga tour ava is around 1.38 (see trackman posts for that data) He avg 1.5 on a driver? 1.5 is the max smash factor your can really get (again see trackman charts and data). To answer your question on SS 6i vs driver I know my kids 9 year old girl can run very close together, even times where she swings her 3w faster than her driver. I think their gap between clubs in terms of speed is a lot less than that of an adult from my experience.

92mph seven iron and 110ish driver here ... maybe driver is too long for him ?

Thanks for the response. I understand what the PGA Tour averages are, but I can only tell you that my son was averaging around 97mph ball speed on 69mph club head speed with his 6-iron, and he had several driver hits that registered over 1.5. I understand that, theoretically, 1.5 is the magic number, but the Trackman tech mentioned that numbers over 1.5 happen due to the way in which Trackman measures the club head. I believe he said that right-handers (like my son) who have a positive AOA and inside-to-out swing are more likely to register over 1.5 smash with drivers.

Driver may be too heavy.