How Fast Does a Green Need to Roll
Having watched the United States Open the past two weeks at Pinehurst I decided to dedicate this blog to green speed, what it is and how it is measured. In recent years golf courses have utilized green speed as a badge of honor that I am not certain is good for the game. Private club members throughout the land will often boast of how fast their greens roll even though many of them cannot control the speed of their putts when playing these billiard table like surfaces.
The speed of a green is measured in what is commonly referred to as as Stimp. The higher the number the faster the green speed. A very acceptable Stimp would be 9 to 10. To put it in perspective the greens at Augusta National during Masters Week usually roll at a 13 as do the greens at the U.S. Open. The number itself is derived through the usage of the Stimpmeter. The usage of the Stimp should be a consideration when setting the cup position into the green. When the Stimp is rolling at a high number hole placement needs to be cut on a grade of slope that is lower (2%-2.5%). Cups should never be cut on grades above 4%. If they are the ball could roll up to the cup and then roll backwards towards the player.
What Is A Stimpmeter? The Stimpmeter is a device manufactured by the USGA that allows a person to measure and place a numerical figure on the speed of a putting surface. It is a helpful management tool for the golf course superintendent but it is not intended for course comparisons.
“The Stimpmeter is an extruded aluminum bar, 36 inches long, with a V-shaped groove extending along its entire length. It has a precisely milled ball-release notch 30″ from the tapered end (the end that rests on the ground). The underside of the tapered end is milled away to reduce bounce as a rolling ball makes contact with the green.”
A ball rolling down the groove has a slight over-spin, which is consistent and does not adversely effect the measurements. The ball-release notch is designed so that a ball will always be released and start to roll when the Stimpmeter is raised to an angle of approximately 20 degrees. This feature ensures that the velocity of the ball will be consistent when it reaches the tapered end.
How is the Stimpmeter used?Begin by selecting a level area on the green, approximately 10 feet by 10 feet. Insert a tee in the green, near the edge of the area selected, to serve as a starting point. Holding the Stimpmeter by the notched end, rest the tapered end on the ground beside the tee and aim it in the direction you intend to roll the ball. Put the ball in the notch and slowly raise the end until the ball starts to roll down the groove. Once the ball starts to roll, hold the Stimpmeter steady until the ball reaches the putting surface. Repeat the same procedure with two more balls keeping the tapered end on the same spot.
- All three balls should come to rest within an 8-inch span. (Should they be farther apart than that, the Stimpmeter may have moved too much during the series, the balls may be damaged or of inferior quality, or unusual conditions may exist. In any event, a pattern larger than 8 inches is of dubious accuracy, and the three-roll series should be repeated.)
- Assuming the balls stop within the prescribed 8- inch limit, insert a second tee in the green at their average stopping point. The distance between the two tees is the length of the first series of rolls.
- Repeat the above process using the second tee as a starting point and the first tee as an aiming point. (In other words, roll a series of three balls along the same line, but in the opposite direction.)
- Measure the two distances – for the first series and the second series – and calculate their average. Record this as the speed of the green.
- Note: Should the difference in length between the first and second series be greater than 18 inches, the accuracy of the resulting average may be questionable. The area selected for the test may not have been sufficiently level – or sufficiently representative of the green – in which case it is advisable to select another area and repeat the test. Sometimes a green may be so severely undulating or sloping that a level area is simply not available (which the data record should indicate).
Who invented the Stimpmeter?
Golfer Edward S. Stimpson, Sr. designed the Stimpmeter in 1935. The Massachussettts state amateur champion and Harvard golf team captain was a spectator at the 1935 United States Open at Oakmont near Pittsburgh, where the winning score was 299 (+11). After witnessing a putt by a top professional (Gene Sarazen) roll off a green, Stimpson was convinced the greens were unreasonably fast, but wondered how he could prove it. He developed a device, made of wood, now known as the Stimpmeter, which is an angled track that releases a ball at a known velocity so that the distance it rolls on a green’s surface can be measured. There have been three Stimpeters used since it was first invented and they are pictured below.
If properly used it can be a wonderful tool. The correct usage is for the green supertintendent to use it as a tool to insure that there is a consistent speed to the greens throughout the golf course. What has happened in recent years is that many clubs have developed a thought process that a green with a very high Stimp is a sign of excellence. This thought process has been further enhanced by the USGA as they do this in their national championships which was in evidence at Pinehurst for the past two weeks. When determining the speed of a green the first consideration should be the percentage of slope that exists in the greens. When you have a high percentage of slope the speed of the green needs to be on the slower side in order to remain fair. Remember that a high stimp will always create more break than a slower rolling stimp. A 20 foot putt rolling across a 3% slope with a Stimp of 9 will have break of 33 inches. The same putt rolling across a Stimp of 13 will have 56 inches of break.