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Gear Effect: Controlling your driver



More than 10 years ago at a university lecture on materials science, it finally dawned on me.

[quote_box_center]“Ah, that’s why a driver is so much more chaotic.”[/quote_box_center]

Last week, I discussed the twisting of the club head on off-center hits, as well as how this causes something called “gear effect.” This week, we are going to understand why a driver can be so infuriatingly difficult to control. It might also explain why you get different results with your irons compared to your woods.

Location, location, location

Where the center of mass of a club is situated is massively influential on the amount of gear effect produced. To help you understand the concept, let’s examine the illustration below.

Photo 1

The illustration shows a “toe hit.” The center of mass (pink gear shape) is traveling along the pink line (swing path). The ball is struck on the toe of the club, and this creates a twisting of that contact point around the center of mass. In other words, the yellow line will twist in the direction of the blue and white arrow, similar to a clock going from 1 o’clock to 3 o’clock.

As the club rotates along the blue part of the arrow, the contact point on the club face will travel more to the right before traveling increasingly more backward (and less rightwards) as it moves along the white part of the arrow.

The bluest part of the arrow (the part where the contact point is shifting more rightwards) is where the most gearing occurs, applying an opposing twist to the ball. So, as the club face opens up clockwise, the ball will rotate counter-clockwise.

Remember that the exact opposite twisting of the clubhead and ball occurs on a shot contacted on the heel of the club.

Iron it out

With an iron, the center of mass is much closer to the face than with a metal wood, so the twisting at impact can produce a different result.

A similar scenario to our driver shot is illustrated below.

Photo 2

The iron is traveling along the pink line and when the ball is hit on the toe of the club, it produces a clockwise twisting of the club face. We can see from the blue-and-white arrow, however, that the iron will behave more like a screen door — rotating nearly straight back with almost no rightward movement of the contact point on the face.

There’s still a little rightward movement, of course, but nowhere near as much as with a driver. As a result, gear effect is minimized and can be overridden by the opening of the face.


Have you ever wondered why the face of a driver is not completely flat? Take a look at your driver now, and you will see that it is slightly convex — something called “bulge.” This was introduced first by Spalding decades ago, and is a way of counteracting gear effect.

With a perfectly flat club face, a toe hit would produce an insane amount of gearing, launching the ball with a lot more hook spin (or less slice spin) than it would have otherwise. By adding bulge, toe hits start more to the right (for a right-handed golfer) and heel hits start more to the left. This gives golfers of all levels a much better chance to hit the fairway when they don’t hit the ball exactly on the sweet spot — which by the way almost never happens, even for the best golfers in the world.

Take action

The first thing to realize with all of this is that a driver is going to be far more difficult to consistently control simply because strike location plays such an important role in direction.

With that said, you should never underestimate the power of simple drills, such as using the dry erase marker, foot spray or face tape to identify your strike location. I see so many golfers hit a heeled slice with the driver and then try and fix their swing path when it was never the issue in the first place.

If you can get better at identifying whether a strike was heeled or toed, as well as improve your ability to hit the desired location, you will see far more consistency in your game.

Here is a simple exercise which can help with the awareness element.

  • Place a dot on the back of the ball with a dry erase marker pen.
  • Hit the shot.
  • Based on the sound, feeling of twisting and the ball flight, try to guess where you hit the club face (too high/low, too heel/toe).
  • Take a look and see how close your guess was to reality.

I have found a clear correlation between a player’s ability to identify where they hit on the club face and their handicap level. I have also seen simple improvements in awareness create lowered handicaps.

Editor’s Note: Adam is Author of the amazon bestseller “The Practice Manual,” where he discusses some of these concepts and more. You can purchase the book here.

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Adam is a golf coach and author of the bestselling book, "The Practice Manual: The Ultimate Guide for Golfers." He currently teaches at Twin Lakes in Santa Barbara, California. Adam has spent many years researching motor learning theory, technique, psychology and skill acquisition. He aims to combine this knowledge he has acquired in order to improve the way golf is learned and potential is achieved. Adam's website is Visit his website for more information on how to take your game to the next level with the latest research.



  1. Todd

    Oct 27, 2015 at 2:22 am

    Who says gear effect is a bad thing?

  2. Jim Maron

    Sep 30, 2015 at 2:44 pm

    I pretty much know where I’ve hit a ball on the face by the feel. You can also tell how well your hitting it as the clubs get older…how small is the circle of wear on the face and where is it relative to the sweet spot.

    Saw an article once the showed the wear circles for a pga tour pro, a scratch and various handicaps 10 to 30….the smaller the circle the better the golfer.

  3. marcel

    Sep 28, 2015 at 9:13 pm

    knowing why you shanking wont help you to improve it – not in golf. yes its good to know why but… without a coach you not gonna be able to fix this 0.5cm difference. thats why the pros have coaches on their bags and during season and off season.

    also the proper fitness – you might have the best coach ever but… if you legs and lower back are not strong and conditioned you fade / you shank / you hook etc. etc. etc. golf is a very physical and precise game to be taken lightly.

  4. Brad

    Sep 27, 2015 at 4:42 am

    Which would have the greatest effect on mis-hits, gear effect or moi? If I was to hit 0,5cm off center which would end up closest to where I was aiming? Would I be correct in saying that for example a G30 driver has a higher moi than for example a SLDR and vice versa, SLDR has less gear effect than a G30 because of where the CG is located?

  5. Hippocamp

    Sep 26, 2015 at 8:59 am

    Thanks for this explanation. Really very clear. Here’s a question. To reduce the gear effect in drivers, it should help to move the center of mass closer to the club face, so it is more like an iron. Weight-forward drivers like some of the low spin models should show a reduced gear effect, right?
    The lack of forgiveness in these clubs would then seem to be more a matter of loss of ball speed at heel and toe rather than a loss of directional control. Or am I missing something?

  6. other paul

    Sep 25, 2015 at 12:31 pm

    Adam, can we get an article on how rate of closure effects gear effect on the face. I have a huge problem with hooks (shut face) and was able to beat it by slowing my closure rate down with a bigger grip. I hit 6/10 dead straight with it. The other 4 weren’t bad either.

    • Adam Young

      Sep 25, 2015 at 1:16 pm

      Hi Paul,
      rate of closure only minimally affects the gearing at impact, but it works in reverse, with a higher rate of closure causing more fade spin. However, this can be easily offset by the club face being more close to the path at impact.

      Gear effect is only really an issue on off-centre strikes. I wouldn’t worry about gearing on middled contacts – be more concerned with face and path relationships. Although, it makes sense that your hook may have minimised as you tried to hit a hold off shot.

  7. John Grossi

    Sep 25, 2015 at 11:44 am

    Adam, thanks for another informative article. I understand toe shots produce hook spin. I have read that the most common miss from mid to high handicap players is a toe shot. Why then do most of these players slice the ball? Based on your previous articles and your book, I am thinking swing path is out to in. It can be confusing. John

    • Adam Young

      Sep 25, 2015 at 12:04 pm

      Hi John,

      The majority of slicers I see hit the ball from the heel. This can sometimes be the cause of the slice, but more often simply correlates with an open face to path and left swing direction.

      I always use marker pens to monitor strike location, and use Trackman to quantify path numbers. I can also get an idea from the face/path/spin axis relationships to see where the ball was hit on the face

  8. Huge

    Sep 25, 2015 at 11:41 am

    You realize this will make no sense whatsoever to high handicappers who can’t hit the ball straight at all. Because all they see, then, in this article’s analysis, is that the driver’s face shouldn’t be this large! They’re going to ask, well, then, why don’t you guys make driver faces and heads the same size as an iron, so there is less twisting???? They’ll also ask you, is this why most players struggle to hit the hybrid properly???? but can hit the iron better?
    So why do we make such huge driver heads?

  9. TR1PTIK

    Sep 25, 2015 at 10:21 am

    I’ve used foot powder spray at the driving range and found it extremely helpful in identifying impact location. Depending on the location of the strike, the sound and feel is entirely different. I now know that a muted “ting” combined with a “hard” impact means that I hit the ball low and out of the heel (my most common miss). A louder “crack” combined with a “medium-hard” to “hard” impact means I was close to center, but high on the face (second most common). A loud “crack” combined with a “soft” impact means I was much closer to finding the club’s CG.

    Good article Adam. Keep it up.

  10. Christestrogen

    Sep 25, 2015 at 9:19 am

    What if the gears were nails?
    Mind blown ***

    • Brian

      Sep 25, 2015 at 9:49 am


    • other paul

      Sep 25, 2015 at 12:28 pm

      Stop picking on the poor guy. He was made fun of a lot for that article. But it is a good starting point for beginners. So you really shouldn’t mock him for it. Not everyone can be a pro WRXer like you… Or me ????

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Wedge Guy: Short iron challenges — and a little insight (hopefully!)



In my experience, almost all golfers could benefit from better short iron play. The ability to hit it closer to where you are looking with your 8-, 9- and P-irons will do more for your scoring than most anything else you can do. So, why is it that so many golfers just don’t hit the quality shots with these clubs that they do and should expect?

I chose this topic in response to an email from Phillip S., who wrote:

“I’m hitting straight and consistent most of the time but I’ve got a big problem between my 8-iron and everything else below.  I can hit my 8-iron 140-145 fairly consistently every time.  I hit my 9-iron somewhere between 110-135.  My pitching wedge is a mystery….it varies between 85 -125 yards.  No matter how “hard” I swing, I can’t seem to hit my short irons consistent distances.  It’s maddening to hit a great drive followed by a pitching wedge short of the green from 110 yards away.  What am I doing wrong?

Well, Phillip, don’t feel alone, because this is one of the most common golf issues I observe. It seems that the lion’s share of technology applied to golf clubs is focused on the long stuff, with drivers and hybrids getting the press. But I firmly believe that the short irons in nearly all “game improvement” designs are ill-suited for precise distance control, hitting shots on the optimum trajectory or knocking flags down. I’ve written about this a number of times, so a little trip back in Wedge Guy history should be enlightening. But here are some facts of golf club performance as applied to short iron play:

Fact #1. Short irons are much more similar to wedges than your middle irons. But almost all iron sets feature a consistent back design for cosmetic appeal on the store racks. And while that deep cavity and perimeter weight distribution certainly help you hit higher and more consistent shots with your 3- or 4- through 7-iron, as the loft gets in the 40-degree range and higher, that weight distribution is not your friend. Regardless of your skill level, short irons should be designed much more similar to wedges than to your middle irons.

Fact #2. As loft increases, perimeter weighting is less effective. Missed shots off of higher lofted clubs have less directional deviation than off of lower-lofted clubs. This is proven time and again on “Iron Byron” robotic testers.

Fact #3. It takes mass behind the ball to deliver consistent distances. Even on dead center hits, cavity back, thin-face irons do not deliver tack-driver distance control like a blade design. In my post of a couple of years ago, “The Round Club Mindset,” I urged readers to borrow blade-style short irons from a friend or assistant pro and watch the difference in trajectories and shotmaking. Do it! You will be surprised, enlightened, and most likely pleased with the results.

Fact #4. The 4.5-degree difference between irons is part of the problem. The industry has built irons around this formula forever, but every golfer who knows his distances can tell you that the full swing distance gap gets larger as the iron number increases, i.e. your gap between your 8- and 9-iron is probably larger than that between your 4- and 5-iron. Could there be some club tweaking called for here?

Fact #5. Your irons do not have to “match.” If you find through experimentation that you get better results with the blade style short irons, get some and have your whole set re-shafted to match, along with lengths and lie angles. These are the keys to true “matching” anyway.

So, Phillip, without knowing your swing or what brand of irons you play, I’m betting that the solution to your problems lies in these facts. Oh, and one more thing – regardless of short iron design, the harder you swing, the higher and shorter the shot will tend to go. That’s because it becomes harder and harder to stay ahead of the club through impact. Keep short iron shots at 80-85 percent power, lead with your left side and watch everything improve.

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Clement: Easily find your perfect backswing plane with this drill



When you get on one of these, magic will happen! You can’t come too far inside or outside in the backswing, and you can’t have arms too deep or shallow at the top of the backswing nor can you be too laid off or across the line either! SEAMLESS!!

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Wedge Guy: The top 7 short game mistakes



I’ve written hundreds of articles as “The Wedge Guy” and I’ve made it my life’s work to closely observe golfers and their short games. So, I thought I’d compile what I see into a list of what I believe are the most common mistakes golfers make around the greens that prevents them from optimizing their scoring. So here goes, not in any particular order:

  1. Tempo. Maybe the most common error I see is a tempo that is too quick and “jabby”. That probably comes from the misunderstood and overdone advice “accelerate through the ball.” I like to compare playing a golf hole to painting a room, and your short shots are your “trim brushes”. They determine how the finished work turns out, and a slower and more deliberate stroke delivers more precision as you get closer to the green and hole.
  2. Set Up/Posture. To hit good chips and pitches, you need to “get down”. Bend your knees a bit more and grip down on the club – it puts you closer to your work for better precision. Too many golfers I see stand up too tall and grip the club to the end.
  3. Grip Pressure. A very light grip on the club is essential to good touch and a proper release through the impact zone. Trust me, you cannot hold a golf club too lightly – your body won’t let you. Concentrate on your forearms; if you can feel any tenseness in the muscles in your forearms, you are holding on too tightly.
  4. Hand position. Watch the tour players hit short shots on TV. Their arms are hanging naturally so that their hands are very close to their upper thighs at address and through impact, but the club is not tilted up on its toe. Copy that and your short game will improve dramatically.
  5. Lack of Body/Core Rotation. When you are hitting short shots, the hands and arms have stay in front of the torso throughout the swing. If you don’t rotate your chest and shoulders back and through, you won’t develop good consistency in distance or contact.
  6. Club selection. Every pitch or chip is different, so don’t try to hit them all with the same club. I see two major errors here. Some golfers always grab the sand wedge when they miss a green. If you have lots of green to work with and don’t need that loft, a PW, 9-iron or even less will give you much better results. The other error is seen in those golfers who are “afraid” of their wedge and are trying to hit tough recoveries with 8- and 9-irons. That doesn’t work either. Go to your practice green and see what happens with different clubs, then take that knowledge to the course.
  7. Clubhead/grip relationship. This error falls into two categories. One is those golfers who forward press so much that they dramatically change the loft of the club. At address and impact the grip should be slightly ahead of the clubhead. I like to focus on the hands, rather than the club, and just think of my left hand leading my right through impact. Which brings me to the other error – allowing the clubhead to pass the hands through impact. If you let the clubhead do that, good shots just cannot happen. And that is caused by you trying to “hit” up on the ball, rather than swinging the entire club through impact.

So, there are my top 7. Obviously, there are others, but if you eliminate those, your short game will get better in a hurry.

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