Heavier club head = ball goes farther?

[Shanks A Million]

No. Well, kind of, because it wasn't written very clearly... he was saying that speed matters more than weight.

This is actually an interesting point. I'll fill in the numbers for you.

A 1 lb weight at 100 mph has 453 joules of energy, while a 100 lb weight traveling at 1 mph has 4.53 joules. As you can see, this means that the lighter object has 100 times as much kinetic energy. A driver weighs about 250 grams, so let's assume that that weight at 100 mph gives us 249 joules. We'll pretend that joules are equal to yards total, which is about right. So a 250g driver swung at 100 mph is equal to a drive of 249 yards. So, if you add 10% to the weight, your driver becomes 275g, which swung at 100 mph is equal to 274 yards. If you add speed, you get 250g at 110 mph, your number is now 302 yards. As you can see, the 10% gave us a return of 27 more yards when it was invested in club speed rather than mass. Now, clubmakers have actually worked on this question for a long time. They, by trial and error, came to the conclusion that a driver head should weigh about 7 oz (198g). To give a bit more info, here's the chart that was created:

[Dobes]

"Now, clubmakers have actually worked on this question for a long time. They, by trial and error, came to the conclusion that a driver head should weigh about 7 oz (198g)."

Shanks, I am still looking for some advice on iron head weight, but, if the curve above is accurate for the 250 gram driver, a driver head speed of 100 MPH would result in momentum of 25,000 units. Increasing the driver head by 25 grams (0.875 oz.) would result in a clubhead speed of about 96 MPH, and a momentum of 26,400 units. Apparently, the heavier driver would have more momentum to transfer to the ball. The ball should leave the clubface with higher velocity, shouldn't it?

A lot of the physics discussed in this thread would apply to a club head on a rope. The momentum transfered to the ball would be equal to the decrease in the velocity of the club times the mass of the club. That decrease in club momentum divided by the mass of the ball should give the velocity of the ball (clubface flex and ball elastic properties not considered). When you replace the rope with a shaft, the player is able to add acceleration (force) to the clubhead to offset some or all of the deceleration at impact, complicating the system. Because the system is very complex, and there are so many influencing factors, I think trial and error is probably the best way to optimize what works for each player.

I am still wondering if I should progressively increase the weight of my long irons ( by, say a max of 15 to 20 grams for the three iron) to get more distance? I know the swingweights would vary, but you will see a tour player choke down two or three inches on a long iron on occasion.

[patriot07]

For the record, the momentum/impact solutions don't apply very well here because the club has a force being applied to it before, during and after impact. Second, the impact in this case isn't even close to rigid body, which changes the math some too.

Energy is a more appropriate way to look at this. And as stated, E=.5mv^2. So yes, if you're going to add 10% weight to go from 250 to 275 grams, you'd have to assume you were only going to lose about 4.9% of your speed. So if you're swinging 100 mph, you'd have to be able to add 25 grams and still swing 95.1 mph to get an equivalent distance, in theory.

I think the reason some of the game's greats used heavier clubs is that they probably:

1. felt like they had more control and
2. didn't see a significant decrease in clubhead velocity between the standard weight and the weight they preferred. From the look of it, both of those guys generated some pretty decent clubhead speed even if they were using heavier drivers.

[Shanks A Million]

"Now, clubmakers have actually worked on this question for a long time. They, by trial and error, came to the conclusion that a driver head should weigh about 7 oz (198g)."

Yes, the human body swinging a club is a more complex thing. No one I've seen has brought up centrifugal force yet, which is a major issue during a golf swing.

For the record, the momentum/impact solutions don't apply very well here because the club has a force being applied to it before, during and after impact. Second, the impact in this case isn't even close to rigid body, which changes the math some too.

I agree, I use a very heavy driver, 355g. It feels easier to control to me, and helps me swing shorter. I don't care if I lose a few yards either, I swing it over 110 mph.

[Shanks A Million]

What are we talking 1-3 mph different... depending on the clubhead weight.

No, not at all. Your assumption is that weight and speed are related linearly, which they are not. Speed is logarithmic, weight is linear.

[Dobes]

So, Shanks, Would you say your driver is 50 grams heavier than an average driver? That seems like a lot of weights. I think I am going to add as much as about 20 grams to my 3 iron ( the max I can add in the undercut cavity and make it look OK cosmetically) and progressively less as the iron numbers get higher to zero grams for the 9 iron. I think my 3 iron head will weigh about 264 g and the 9 will weigh 285. Do you think this will slow my swing speed enough to hurt my distance? I know they will feel better. Thanks.

[dreamsmith]

Let me give you the scientific answer: All physics equations, including that for the max energy (that's what you're talking about), have the term "mv2 (where the '2' means the exponant - squared. So the higher the mass (weight) the more energy is imparted. BUT, the higher the speed (v), the higher the energy by a SQUARE factor! The energy to the ball equals the weight of the object hitting it multiplied by the velocity of the object SQUARED! The speed of the club is much, much more important than the weight of the club. And guess what? You can swing a lighter club much faster!

Why do you think major league sluggers use light bats?

[Shanks A Million]

Let me give you the scientific answer: All physics equations, including that for the max energy (that's what you're talking about), have the term "mv2 (where the '2' means the exponant - squared. So the higher the mass (weight) the more energy is imparted. BUT, the higher the speed (v), the higher the energy by a SQUARE factor! The energy to the ball equals the weight of the object hitting it multiplied by the velocity of the object SQUARED! The speed of the club is much, much more important than the weight of the club. And guess what? You can swing a lighter club much faster!

But again, while 100% correct in a purely scientific sense (i.e. E = ½MV²), the issue of control also comes into play. A driver that weighs too little could not have as much MOI, and at some point, the speed gained through a loss of weight would be negligible. With little MOI, the penalty on an off center hit becomes substantial, and the actual ballspeed realized through a series of hits would actually be lower. What clubmakers are interested in is having the

average outcome as long and straight as possible.

[lcfd42]

OK I can see this coming. Someone needs to set up a swing robot using different sized/weighted club heads (using Irons only as described by the OP) and swing them all at the same speed into a impact sensor that would provide such data as kinetic energy, momentum, and total energy transfer at impact. This way you would have scientific data to compare against. If you are asking for data in any other way, not removing as many variables as possible (ie - human effect) your findings will always be in error.
I am in complete agreement that club weight preference will differ between golfers, and may aid some players in hitting longer. These differences would most likely come from weight aiding the swing. Think of them like a weighted swing trainer that uses weight to help you get on plane and train your hand position. Lighter clubs will play to a purer ball striker who will hit the ball longer than someone who is not anyway. All of these variables have to be accounted for or eliminated in these type discussions.
Scientific facts will never change until the laws of physics can be bent or even broken.

[GenZen]

Yes for me. I use a 8.5 degree TaylorMade R9 TP and increased the weight from 1gm 16gm 1gm to 12gm 16gm 12gm and I also use a Graphite Design YSQst 75gram S Flex shaft. My average drive has gone up from 260 (carry) to about 280+ (carry).

None of the answers deal with the physics of the golfer. I am 240 lbs. and can bench 350 pounds and curl 45 pound weights. My average swing speed is about 98 mph. Lighter driver don't increase my swing speed.

It was much easier for me to increase the weight of the club by 22grams and shaft from 65grams to 75grams then change my swing to add more weight.

Also, the added weight has drastically increased my accuracy. My tempo also has slowed down but my ball goes father.

Most drivers are made for average golfers. Most average golfers can't bench 350lbs. If you are strong but have moderate swing tempo, I would recommend increasing the overall weight and swing weight of the driver.

BTW - I can hit a Power Hitter Driver (310) about 240 yards. 310 is too heavy even for me but I always hit the fairway!

GenZen

FYI - Graphite Design YSQst shaft is awesome. It lowered my flight hence increasing my rolls. It produces a lower flight then the stock TP Fujikura F1 shaft for me.

[Shanks A Million]

Yes for me. I use a 8.5 degree TaylorMade R9 TP and increased the weight from 1gm 16gm 1gm to 12gm 16gm 12gm and I also use a Graphite Design YSQst 75gram S Flex shaft. My average drive has gone up from 260 (carry) to about

I see you've been playing golf on the moon.

[fseoer2010]

The thing I noticed when I bought my Burner was the "lightness" allowed for and easier and more controllable change of direction at the top of the swing, which made it much easier to come back to the ball accurately. If you cannot get the head back to the ball the added weight will not help!

[ghalfaire]

A engineer would say the kinetic energy of an object (the club head in this case) in motion is directly proportional to the mass of the object and proportional to the square of the velocity of the object. So if you increase the mass of the object (club head) by 10% the kinetic energy goes up 10% (assuming you can still swing the club at the same velocity). But if you can increase the velocity 10% the kinetic energy goes up 21% (everything else remaining equal). So in the first approximation of energy transfer to the ball at the collision with a club head in motion it is better to work on increasing your club head speed and don't buy lead tape to increase club head mass. So in other words, if you work on increasing your club head speed you will hit the ball farther than if you just go to a heavier club head (which by the way might decrease your club velocity due to factors not discussed here, which could yield shorter drives).

[Dobes]

Nice to see a renewed discussion on the topic. I am still not convinced by the energy (velocity squared comparison) argument. The laws of physics require conservation of both energy and of momentum. Temperature of the objects involved in the collision before and after the impact factor into conservation of energy. How much energy, who knows. The conservation of momentum is a simpler concept for me to grasp and is dependent only on the velocities and masses of both objects before and after the impact - and that is strictly a linear relationship - mv, and are easily measured. The ability to add acceleration and additional force during contact by a stronger player may account for his ability to hit farther, also. If he can reduce the loss of velocity of the club, more momentum will be transferred to the ball. Those of you arguing the energy approach don't factor in the energy of both objects after impact. I think the momentum approach is more real world, while energy conservation is a more theoretical discussion.

[Varsity_Golf]

I suppose it could create more inertia/momentum, but it doesn't seem to make sense why you would want to carry a heavier club.

[65withatriple]

That's the problem with your thought right there: you can't swing the heavier one as fast as the lighter one.

Thats not completely true. There is a optimal weight to achieve maximum swing speed. Too light and you will lose speed. Do you think a pitcher can throw a golf ball as fast as a baseball?

[Dobes]

Now that I read my own post, I realize that, while the velocity of each object after impact could be measured with high speed video, a lower final club head speed would seem to indicate more momentum transfer to the ball. It would seem that a lighter club might be likely to be slowed down more by the impact, and transfer more momentum to the ball, but that doesn't explain everything that is going on. The force being applied to the club head during contact would be working to reduce the deceleration of the club head, and must be a major factor.

Again, I think the ability of the golfer to add force through the contact time period is a major factor. A swing that accelerates from the top of the golf swing all the way through impact would seem to give the best result. Club weight, player strength and swing speed and tempo are different for every player. The player's ability to find his optimum for these factors is probably the key. A momentary hesitation at the top of the backswing may help him to build build club head speed from zero to a maximum through the point and time of impact. Does this explain good tempo and the nice result?

[Shanks A Million]

Now that I read my own post, I realize that, while the velocity of each object after impact could be measured with high speed video, a lower final club head speed would seem to indicate more momentum transfer to the ball. It would seem that a lighter club might be likely to be slowed down more by the impact, and transfer more momentum to the ball, but that doesn't explain everything that is going on. The force being applied to the club head during contact would be working to reduce the deceleration of the club head, and must be a major factor.

I had posted this earlier, but studies were done and a supposedly optimal weight was found for driver heads. They took into account the factors you mentioned. About 200 grams is where the optimal head weight is.