If the club length fitting result gives the change of more than 1 inch (2,5 cm) it makes significant difference in Swingweight (SW) and Moment of Inertia (MOI). This effect could be partially compensated by adjusting lie angle, but it may not be fully compensated.
The well-known rule of thumb says that ¼” of length trades with 3 grams of the clubhead weight. In truth it is the general estimation estimation only.
The calculator below shows more precisely how to neutralize the heft changes caused by length fitting. It indicates the weight that should be added to or subtracted from the club head to fully compensate the heft for the length changes and keep:
- Swingweight unchanged, or
- MOI unchanged
after the given length change.
See the picture below for how to measure the distance of the balance point (Center of Mass) from the butt.
update: September 2021