This chart from trackman has encouraged me to ask some serious questions about it’s validity and accuracy. Depending on the iron head, the location of the cog and a few other factors the amount of gear effect should change.
To simplify into a one size fits all system seems below trackman, so I’m going to dig for answers.
I’ve started an extensive research project with some of the best in the world. A club fitter from the UK, an engineer, a trackman employee/teacher from the UK and myself. I’ll keep you posted on what turns up.
I’ll keep you posted.