What is Waggle Factor

By Frank ThomasFebruary 25, 2010, 7:10 pm

Hi Frank,

You recently talked about wearing a glove and how it can affect the swing weight of a club, and I imagine wearing a watch might do the same? But my real questions are: What is swing weight? How does it affect the quality of the swing or the results? And how do I know/figure out what is the proper swing weight for me?

Thank you very much

– Brian


To your first question; What is swing weight?

A great amateur golfer, Francis Ouimet, won various events which included the U.S. Open in 1913. He selected his clubs based on feel – an undefined term but most of us seem to have a general idea what it means. If you waggle the clubs in your set, they should all feel the same, i.e. have the same waggle factor.

Because Francis Ouimet was such a good golfer, his clubs – matched by feel-- were used to develop a balance system. This was done by hanging a weight (approximately 16 ounces) on the grip end of each club and finding a common balance point (fulcrum) from the butt end for each club. This balance point was 14 inches from the butt. Thus, the swing weight system was born in about 1920 and still used today. The swing weight is not described as the amount of weight needed to balance a club but by an alpha-numeric table such as D2 or C9 etc.

Swing weight is a questionable system for several reasons. First, it implies a dynamic measurement which it is not. Second, it can be abused by back weighting or adding weight down the shaft purely to get the same or desired number. Third, it is not very well understood.

Having said this, it must be noted that pure swing weight – variations in shaft length and head weight only – is a good first step in matching clubs, as this is closely related to the waggle factor a term I coined because it is so descriptive.

This waggle factor should be called matching by moment of inertia (MOI). This is a much better method of matching clubs as it takes into account the weight, length and is a true dynamic measurement. If you hold a club at the grip end and waggle it, you will experience a specific resistance every time you change direction back and forth. This relates directly to the MOI of the club about the axis you are waggling it i.e. the grip.

Now turn the club around, holding its head and waggle it. You will find the resistance to changing direction is reduced significantly. The MOI has changed and it feels different. Francis Ouimet, unbeknownst to him, was matching his clubs by the MOI method –  the waggle factor.

Most of us know, having mentioned it several  times in Q&As over the last year, that wearing a glove will alter (decrease) the swing weight of the club by about five points, but will not noticeably affect the feel of the club.
The glove will not change the waggle factor (MOI) measurably.

Brian, now that we are over that explanation, let me say that in general terms the higher the swing weight (pure swing weight), the heavier the head and the more resistance you will feel to swinging the club to generating the same head speed.

After about 400 years of trial and error we have found that a swing weight in the range of about D0 to D3 is a good number for most male golfers. Females generally migrate to about C6 to C9. This, in most cases, is because the shaft length is about 1-inch shorter than men but the head weight is about the same.

So Brian a good starting point for you – as for most men -- is about a D0 or D2.

I am sure we will soon be matching clubs by MOI, which uses a relatively simple scale and takes into account all those variables used in swing weight, but is a dynamic measurement and more meaningful.

Waggle your way around this one, Brian.

– Frank


Frank Thomas, inventor of the graphite shaft, is founder of Frankly Golf. Thomas is chief technical advisor to GolfChannel.com. He served as technical director of the USGA for 26 years and directed the development of the GHIN system and introduced the Stimpmeter. To email a question for possible use in an upcoming Let's Be Frank column, please email letsbefrank@franklygolf.com

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By Will GrayJuly 16, 2018, 5:15 pm

Dustin Johnson heads into The Open as the top-ranked player in the world, and he's also an understandable betting favorite as he looks to win a second career major.

Johnson has not played since the U.S. Open, where he led by four shots at the halfway point and eventually finished third. He has three top-10 finishes in nine Open appearances, notably a T-2 finish at Royal St. George's in 2011.

Johnson opened as a 12/1 favorite when the Westgate Las Vegas Superbook first published odds for Carnoustie after the U.S. Open, and he remains at that number with the first round just three days away.

Here's a look at the latest odds on some of the other top contenders, according to the Westgate:

12/1: Dustin Johnson

16/1: Rory McIlroy, Rickie Fowler, Justin Rose

20/1: Jordan Spieth, Justin Thomas, Tommy Fleetwood, Brooks Koepka, Jon Rahm

25/1: Jason Day, Henrik Stenson, Tiger Woods

30/1: Sergio Garcia, Francesco Molinari, Paul Casey, Alex Noren, Patrick Reed

40/1: Hideki Matsuyama, Marc Leishman, Branden Grace, Tyrrell Hatton

50/1: Phil Mickelson, Ian Poulter, Matthew Fitzpatrick

60/1: Russell Knox, Louis Oosthuizen, Matt Kuchar, Bryson DeChambeau, Zach Johnson, Tony Finau, Bubba Watson

80/1: Lee Westwood, Adam Scott, Patrick Cantlay, Rafael Cabrera-Bello, Thomas Pieters, Xander Schauffele

100/1: Shane Lowry, Webb Simpson, Brandt Snedeker, Ryan Fox, Thorbjorn Olesen

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Woods needs top-10 at Open to qualify for WGC

By Will GrayJuly 16, 2018, 4:34 pm

If Tiger Woods is going to qualify for the final WGC-Bridgestone Invitational at Firestone Country Club, he'll need to do something he hasn't done in five years this week at The Open.

Woods has won eight times at Firestone, including his most recent PGA Tour victory in 2013, and has openly stated that he would like to qualify for the no-cut event in Akron before it shifts to Memphis next year. But in order to do so, Woods will need to move into the top 50 in the Official World Golf Ranking after this week's event at Carnoustie.

Woods is currently ranked No. 71 in the world, down two spots from last week, and based on projections it means that he'll need to finish no worse than a tie for eighth to have a chance of cracking the top 50. Woods' last top-10 finish at a major came at the 2013 Open at Muirfield, where he tied for sixth.

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There are actually two OWGR cutoffs for the Bridgestone, July 23 and July 30. That means that Woods could theoretically still add a start at next week's RBC Canadian Open to chase a spot in the top 50, but he has said on multiple occasions that this week will be his last start of the month. The WGC-Bridgestone Invitational will be played Aug. 2-5.

There wasn't much movement in the world rankings last week, with the top 10 staying the same heading into the season's third major. Dustin Johnson remains world No. 1, followed by Justin Thomas, Justin Rose, Brooks Koepka and Jon Rahm. Defending Open champ Jordan Spieth is ranked sixth, with Rickie Fowler, Rory McIlroy, Jason Day and Tommy Fleetwood rounding out the top 10.

Despite taking the week off, Sweden's Alex Noren moved up three spots from No. 14 to No. 11, passing Patrick Reed, Bubba Watson and Paul Casey.

John Deere Classic champ Michael Kim went from No. 473 to No. 215 in the latest rankings, while South African Brandon Stone jumped from 371st to 110th with his win at the Scottish Open.

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Spieth takes familiar break ahead of Open defense

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CARNOUSTIE, Scotland – As his title chances seemed to be slipping away during the final round of last year’s Open Championship, Jordan Spieth’s caddie took a moment to remind him who he was.

Following a bogey at No. 13, Michael Greller referenced a recent vacation he’d taken to Mexico where he’d spent time with Michael Phelps and Michael Jordan and why he deserved to be among that group of singular athletes.

Spieth, who won last year’s Open, decided to continue the tradition, spending time in Cabo again before this week’s championship.

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“I kind of went through the same schedule,” Spieth said on Monday at Carnoustie. “It was nice to have a little vacation.”

Spieth hasn’t played since the Travelers Championship; instead he attended the Special Olympics USA Games earlier this month in Seattle with his sister. It was Spieth’s first time back to the Pacific Northwest since he won the 2015 U.S. Open.

“I went out to Chambers Bay with [Greller],” Spieth said. “We kind of walked down the 18th hole. It was cool reliving those memories.”

But most of all Spieth said he needed a break after a particularly tough season.

“I had the itch to get back to it after a couple weeks of not really working,” he said. “It was nice to kind of have that itch to get back.”