Standard Iron Shaft Length/Swing Weight

[bladeputter_11]

I'm putting new graphite shafts in my irons that had steel shafts in them.  I went on Golfworks website to get the standard lengths of iron shafts.  They have one set of lengths for steel shafts and another set of numbers for graphite.  All graphite measurements were .5 inches longer than the steel measurements.  I thought swing weight to be a basic principal of physics.  If the head is heavier in relation to the weight of the golf shaft, the swing weight goes up.  If graphite shafts are typically lighter than steel shafts wouldn't it stand to reason they'd at least be the same length.  There's also the overall weight of something that should be considered but that's not what "swing weight" is.  Am I missing something?  Why would standard graphite shafts length be a half an inch longer?

[Adam C]

Depending on the OEM, different brands will have either matching lengths in steel and graphite or go with the 1/2 over with graphite. However when they match them for length, the SW is usually 3 or 4 points lighter with graphite. SW can be tricky because it's not just the head weight, it's the relation of the head to the shaft and grip while also factoring in the shaft length and balance point.

This means that for every 1/2 change in length, you get a 3 SWP change (longer=heavier). Also for every 9 grams of shaft weight change, you get 1 SWP change (heavier=heavier). Since the average stock graphite shaft is around 30g lighter than the matching steel, 1/2 longer shafts balance things out at least on a swing weight scale.

[bladeputter_11]

Thanks for your reply Adam C.  If graphite shafts are lighter wouldn't the swing weight go up?  If I have a two identical 4 irons but the only difference is one has a 38.5" steel shaft and one has a 39.5" graphite shaft, wouldn't the swing weight be heavier on the graphite club?

Edited December 4, 2020 by bladeputter_11
wording

[Adam C]

You need to remember that the fulcrum for a swing weight scale sits at 14 inches from the butt end of the club. That means that the majority of whatever shaft you are using will be out past the fulcrum. Therefore the shaft weight plays a greater influence on the head side of the club vs. the grip and why a heavier shaft will increase SW more than a lighter one.

Of course there are also shaft balance points to take into consideration but for this example I am assuming our hypothetical shafts are the same other than material and weight.

Your example above would depend on the weights of the two shafts since 38.5 to 39.5 would usually equal 6 SWP. Your weight difference breakeven would be around 54g to tip the scale either way.