Just looking at the four biggest wood brands (Callaway, Taylormade, Ping and Cobra) there are 34 different driver shaft weight options in 2018, and that’s before you even start looking at custom or upgrade options. In the past, great drivers came with a standard stock shaft in either a regular or stiff flex, but things have changed dramatically. Macniven even says “shaft weight is more important today than shaft flex”, saying that “golfers can just about get away with playing the wrong shaft flex, but getting the wrong weight can absolutely kill your game”.
Think about it like this; each swing is individual to its owner and how the club is delivered at impact is different for everyone. A long, languid swing can create the same amount of speed as a short, punchy one, but how each loads the shaft is very different. A short, punchy swing might want a heavier shaft while the longer, languid one might well go into a lightweight model.
Macniven says: “Getting the shaft weight wrong means you could hit shots horribly, with ball speed and dispersion being all over the place. It’s likely distance will go down, dispersion will go up.” But often golfers don’t even realise why they’re hitting those bad shots, which explains why shaft weight should be centre stage when considering a new driver.