Gear Effect with Irons

October 26th, 2009 by John Graham Leave a reply »
Let’s start with a chart from trackman. Basically, what this chart shows is how off center hits effect the flight of the ball. Trackman determines a theoretical ball flight based on the d plane and it’s impact conditions it measures. Based on the actual flight of the ball, trackman computes where the ball must have hit the face to create the actual ball flight relative to the theoretical flight that should have occured.

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.

Trackman Chart with Gear Effect on Irons

Trackman Chart with Gear Effect on Irons



  1. David C says:

    The impact physics arent as simple as TM suggest.

    In reality, the amount of direction imparted by the club depends on its impact loft too, from all face angle with a vertical impact, like a putter, to more swing path once you get over 45degrees. It is easy to try and see this.

    In addition there is club head rotation imparted by the golfer and at impact, the centre of gravity of the club etc. All this tends to get lumped under ‘gearing’.

  2. Dave says:

    What exactly are you trying to determine with your research project John? I may be willing to help – contact me privately for details.

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