One Little Caveat…
So, I may have left out one little detail from the last 4 lessons on ball flight: all of those rules assume that you hit the ball directly on the sweet spot (Center of Gravity).
No problem for you, right? I mean, really, who misses the sweet spot?
Oh, you do? That’s ok, so do I. Not a problem, though, we just need to understand what that does to the ball flight, and that’s what I’m covering in this final lesson: Gear Effect.
What Is Gear Effect?
Gear effect is the term used to explain how and why hitting the ball off-center changes the ball flight.
When the ball contacts the face somewhere other than the Center of Gravity (CoG), it causes the face to change its orientation and affects the spin. This is because during impact, the ball and face are enmeshed like two gears (hence the name).
The further apart the CoG of the ball and the club are, the more gear effect there is. Translation: there’s lots of gear effect with a driver, but little or none with wedges.
Technical definitions are great and all, but I promised practical knowledge. Here it is in four simple bullet points:
- When you hit the ball high on the face, it will launch higher and spin less. This is optimal for your driver…assuming you want to hit it far.
- When you hit the ball low on the face, it will launch lower and spin more. This is very bad for your driver.
- When you hit the ball on the toe, the ball will launch towards the right but draw/hook to the left.
- When you hit the ball on the heel, the ball will launch towards the left but cut/slice to the right.
What You Should Do
The next time you’re on the range, bring some impact tape and keep track of where on the face you’re hitting the ball. If you don’t have impact tape, foot spray will work, too (spray the face of the club and look for the ball mark). A third option is to dot the ball with a dry-erase marker and “aim” the dot squarely at your club.
Hit 10 or 15 shots and note your tendencies. If you’re consistently low on the face, you’re robbing yourself of distance. If you’re consistently hitting the ball on the toe or heel, then impact location, not face or path issues, may be to blame for your inaccuracy.
That’s All Folks
I hope that you have found this series to be helpful.
In the future, I will be putting out more tips on how to improve your club face control, club path, and centered contact, as well as a comprehensive lesson on diagnosing your ball flight. I welcome any feedback on specific tips or information you’d like to see.
Understanding Ball Flight
Part 4: 3D Club Path (Resultant Path)
Part 5: Gear Effect
Watch the Video
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any clubs out there with all sweet spot? got no time to practice mate.
Haha! If you believe the manufacturers, the newest clubs are all sweet spot, but unfortunately that’s not the case. While very forgiving clubs have large areas that deliver high ball speed, a club can only have one center of gravity.
This series has been great Matt! Really appreciate the time you’ve put into this – it really is helpful. I need to get some impact tape.
One query – with the low/forward CG drivers that are becoming more popular now (SLDR, Jetspeed for instance) I imagine this will only change where the reference point is with regard to the sweet spot?
Thank you, Brad, I appreciate that.
You are absolutely right about the low, forward CG clubs. The reason for the low, forward CG is that it makes it easier to create “positive gearing”/hitting it above the CG because the CG is so low.
Additionally, there should be less gear effect if the CG is forward as compared to a deeper CG.
does forward CG impact spin? don’t want any additional spin reducing distance on my deep bombs.
A forward CG, which should lessen the impact of gear effect, could change spin positively or negatively, depending on your impact location. If you rely on hitting the ball above the CG to reduce spin, less gear effect would not be a good thing. However, if you hit the ball below to CG, less gear effect would be a good thing.
Based on what I know about your game, you always hit the CG, so it probably doesn’t matter.
Green painter’s tape or even plain old masking tape works fine, too.
I love the first image in this article. Such a clear explanation.
Thanks for this entire series Matt, it’s been a great read and I’ve learned quite a bit!
You have the monopoly on useful intnomafion-arer’t monopolies illegal? ;)
Enjoyed your series on ball flight laws. However ,it would be refreshing to have an instructor ,just one time,explain it for a left-handed golfer so righties would have to constantly be reversing everything you say, puting them a step behind in grasping what you are explaining.
Thanks Matt. Just read your 5-part series on ball flight laws. Very helpful and simply laid out. One issue for me with many articles like this is that I am a lefty. For the most part, I am successful at flipping side-language to adopt it for a lefty. However, the Gear Effect is a different concept. You have the “simple bullet points” section just before the impact tape photo. Do I flip the heal and toe strike results to coincide with a lefty stance or are the results (slice/hook) universal? I realize the high/low is the exact same… Thanks again!
Good question. The following correlation applies for lefties or righties: heel = cut, toe = draw.
Great question. Here’s the universal rule:
Heel = Cut
Toe = Draw
Great information. Thank you.
Very informative. I still don’t understand the nitty gritty physics of the gear effect…but alas, I probably never will. Very counterintuitive.
My question for you if you are still around in 2018 is how CG location in irons and wedges, i.e. club head design, affects ball flight and spin. I’ve heard lower CGs in game improvement irons produce higher ball flights and MORE spin, which is counter to the gear effect explained above on the driver. Is this the club head CG having more of an effect on the ball, rather than the other way around?
CG acts the same in all clubs, but in irons and wedges the CG is much closer to the face and ball, so there’s far less gear effect. Low CGs in irons will produce high launch with LOW spin. That (combined with stronger lofts) is why irons are so long these days.
Also, does face flex have any effect on ball flight?
My understanding is that it does not, or at least that the effect is not significant.
Awesome! Thanks for the feedback. I read a lot from the Tutelman website on gear effect and CG location last night, and that cleared a lot of stuff up too…Finally understand it all!
Matt, Interesting discussion of spin. I guess theoretically at the same clubbed speed, if you had a firmer grip and allowed less club deflection then you would get less tilt of the spin axis. Am I thinking correctly?
Face bulge on woods tries to neutralize axis tilt and with irons the backspin is so much stronger it neutralizes axis tilt with the gyroscope effect.
I’m curious though. Theoretically if the lie of the club was tilted at impact that should tilt the axis also, right? A slightly toe down club face would fade and slightly toe up face would draw. I wonder which might be greater then, path or shallow/steepness of plane? (..and are interrelated of course.)
Theoretically, if you could keep the club from deflecting at impact, there would be no gear effect…I think.
I’m not sure that I understand the second part of your question.
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So here is a quick question for you, if you don’t mine, just to make sure I have this correct in my head. Theoretically… if you try and drop your hands and hit further from the inside and rotate properly Face closes sooner, path is inside out, face is open though it still goes straight. Unless its hit in the toe, then it starts out high but draws then it would still create the right to left flight you were looking for but the wrong way? Does that make sense? Vice-Versa if you attempt to come across the ball to hit a fade, but don’t you just have the path outside in and the face open to even it out yet strike the heel, it produces a lower flighted cut shot w/ tons of spin? So theoretically, you could be changing the face to path for not reason if it was zeroing out, just using that as a vector to change where you hit the ball on the face?
Respectfully, I’m having a hard time understanding your question. Anytime you say “open” or “closed” there needs to be a reference – “face open to path” could be different than “face open to target”.
Also, for simplicity sake, let’s forget about the swing mechanics and stick to the facts of impact. It will help us to get a clearer picture.
Hi Matt: I made a drawing (with text) describing the confusion I am experiencing regarding your “spin” articles which seems to contradict the “gear” effect article. Do you have an email address to which I could forward this PDF file I created?
Hi Matt, I have some problem with the slice/hook “spin on the ball” and the gear effect spin.
If one hits a ball in the centre from the “inside out” path, the ball spins counter-clockwise (as seen from above) and hooks. [An “outside in” path with a centre hit produces a ball that spins clockwise (as seen from above) and the ball slices.]
Now, hitting a ball on the toe of the driver (the face is open) produces a clockwise spin and therefore the ball should slice but it does the opposite and hooks! Similarly, hitting the ball with the heel of the driver (the face is closed to the path) should cause the ball to hook but it does the opposite!
I’m unsure what you’re trying to get at. Hitting the ball on the toe will add hook spin. Hitting the ball on the heel will add cut spin. Gear effect can be offset with face-to-path, but it’s always there.
I’ve sent you a PDF file with drawings from your slice and hook tutorial that hopefully explains my confusion better than my above text does! Thanks!
The face opening as a result of impact is not the same as the player presenting an open face at impact.