What it is Stimp
Stimp is the standard measure of how fast a green rolls, expressed as a distance in feet: a ball released from a standard ramp, called a stimpmeter, rolls that far on the flat. Higher number, faster green. Lower number, slower green.
Why the speed of your green matters
Let’s do an excursion into basic physics. The break of a putt is determined mainly by four factors: its distance, gradient, green speed, and power – if we neglect external factors like weather and grain (learn more about their influence here). As distance and gradient are given for a specific putt, green speed and power remain the only variables in this equation. We want to focus on green speed here, so we assume we want to hit the ball at a pace where it would finish one foot past the hole.
If the green is now running fairly slow, for example a 6 on the Stimp scale, the putt would need to be hit at a higher speed, giving gravity less chance to pull the ball down the slope against a higher friction of the longer grass blades and therefore causing the ball to break less. For a 10-foot putt on a 2% slope, that would mean you have to aim 5 inches outside the edge of the cup.
If the green is now running a lot faster, for example 15 on the Stimp scale, the putt would need to be hit much softer, giving gravity more chance to pull the ball down the slope against a lower friction of the shorter grass blades and therefore causing the ball to break much more. For a 10-foot putt on a 2% slope, that would mean you have to aim 16 inches outside the edge of the cup.
What to do with it
This example illustrates why it is so important to set the Stimp correctly in the PuttView app. In fact, it is the most important setting for line accuracy within the app. Expect slower greens in winter and after rain, faster ones in dry summer conditions. If you can, ask the greenkeeper. They measure it daily and will tell you. Otherwise, the pro shop, starter's desk or club app often post it.
You don’t know how to find out at what speed your green is running? Check our Video “Adjust Stim (Green Speed) first”.