Backspin Myth?

I don't think it is so much the ball rolling up the club face as it is the club face striking down on the ball and using the grooves to grip the ball and put backspin on it. I know after I hit an aggressive wedge shot I can look at the club face and see chunks of the ball in the grooves.

First, Lee's mistaken in terms of how bounce works. The clubhead doesn't "bounce" into the ball while the ball is on the clubface. But he's right in that you don't want to severely de-loft the clubface to get a lot of backspin. You want a difference between angle of attack and dynamic club loft to create a high "spin loft."

As to the dynamics of impact with higher lofted clubs, here's what happens.

The ball slides up the clubface but it's a relative thing - the clubhead is going down. The ball is only ever going upwards and forwards - it's never going "down" unless you top it. The clubface - the dynamic loft - is still "more important" than the path of the club (downward), so the ball never goes down. As the clubface goes down and forward, the ball is going up and forward. The grooves on higher lofted clubs help to grab the ball and you effectively generate a system like two gears - the back of the ball meshes with the "gears" on the clubface, and both go "down." This creates backspin.

Maximum backspin is caused when the ball grips the clubface the most, when the ball is halfway through the impact interval and at max compression. The CG of the ball projected onto the clubface will often be a groove or so higher than the initial impact point, again because not only is the ball moving upwards, but the clubhead is moving downwards.

So yes, the ball moves up the clubface during impact, but I don't know that I'd call it "rolling" up the clubface per se. If you had a ball that didn't "compress" at all, you'd get virtually no spin on the ball at all. That compression is why urethane balls (softer cover) spin more around the greens than surlyn balls - the softer outer cover is all that can "compress" against the clubface on short shots without a lot of clubhead speed.

Thumbs up for that.

Quote:

Originally Posted by iacas 

First, Lee's mistaken in terms of how bounce works. The clubhead doesn't "bounce" into the ball while the ball is on the clubface. But he's right in that you don't want to severely de-loft the clubface to get a lot of backspin. You want a difference between angle of attack and dynamic club loft to create a high "spin loft."

 

As to the dynamics of impact with higher lofted clubs, here's what happens.

 

The ball slides up the clubface but it's a relative thing - the clubhead is going down. The ball is only ever going upwards and forwards - it's never going "down" unless you top it. The clubface - the dynamic loft - is still "more important" than the path of the club (downward), so the ball never goes down. As the clubface goes down and forward, the ball is going up and forward. The grooves on higher lofted clubs help to grab the ball and you effectively generate a system like two gears - the back of the ball meshes with the "gears" on the clubface, and both go "down." This creates backspin.

 

Maximum backspin is caused when the ball grips the clubface the most, when the ball is halfway through the impact interval and at max compression. The CG of the ball projected onto the clubface will often be a groove or so higher than the initial impact point, again because not only is the ball moving upwards, but the clubhead is moving downwards.

 

So yes, the ball moves up the clubface during impact, but I don't know that I'd call it "rolling" up the clubface per se. If you had a ball that didn't compress at all, you'd get virtually no spin on the ball at all. That compression is why urethane balls (softer cover) spin more around the greens than surlyn balls - the softer outer cover is all that can compress against the clubface on short shots without a lot of clubhead speed.

Quote:

Originally Posted by The Recreational Golfer 

Is this notion of the ball crawling up the clubface before flying off of it a golfing urban legend?

 

This video does a pretty good job of showing the dynamics of the clubface striking the ball for a variety of different clubs.    Take a look and draw your own conclusions about the ball crawling up the face.

Quote:

Originally Posted by slabm7 

I don't think it is so much the ball rolling up the club face as it is the club face striking down on the ball and using the grooves to grip the ball and put backspin on it. I know after I hit an aggressive wedge shot I can look at the club face and see chunks of the ball in the grooves.

You are mistaken in thinking that spin is applied by the grooves gripping the ball.  Backspin is applied by the friction between the ball and the clubface.  Spin is nearly unchanged on a clean hit with a club which has no grooves at all.  This has been proved through testing several times by different agencies.  The grooves only assist in creating more friction by channeling grass and debris away from the contact area when the lie is less than perfect.

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Originally Posted by Fourputt 

You are mistaken in thinking that spin is applied by the grooves gripping the ball.  Backspin is applied by the friction between the ball and the clubface.  Spin is nearly unchanged on a clean hit with a club which has no grooves at all.  This has been proved through testing several times by different agencies.  The grooves only assist in creating more friction by channeling grass and debris away from the contact area when the lie is less than perfect.

Exactly. The same principle applies to tires - slicks (non-treaded tires) provide the best grip in the dry and sometimes even on wet surfaces as long as there is no standing water. Tread is only good when you need to channel away a lot of water.

Quote:

Originally Posted by Fourputt 

You are mistaken in thinking that spin is applied by the grooves gripping the ball.  Backspin is applied by the friction between the ball and the clubface.  Spin is nearly unchanged on a clean hit with a club which has no grooves at all.  This has been proved through testing several times by different agencies.  The grooves only assist in creating more friction by channeling grass and debris away from the contact area when the lie is less than perfect.

That's not entirely true. A groove less club from a clean lie will generate the same amount of spin as a grooved club up to about a 5-iron's loft. Beyond that, the "edges" of the grooves (the edges that were recently softened by rule) start to play a role in how much spin can be applied. The "no grooves" thing stops being real at about 25 degrees, IIRC.

It's not a lot, but to say that the grooves don't play a role at all is wrong.

I don't know what percentage it is - it might be 5-10% of the spin - but it's not insignificant and it's definitely not 0%.

Quote:

Originally Posted by iacas 

 

That's not entirely true. A groove less club from a clean lie will generate the same amount of spin as a grooved club up to about a 5-iron's loft. Beyond that, the "edges" of the grooves (the edges that were recently softened by rule) start to play a role in how much spin can be applied. The "no grooves" thing stops being real at about 25 degrees, IIRC.

 

It's not a lot, but to say that the grooves don't play a role at all is wrong.

 

I don't know what percentage it is - it might be 5-10% of the spin - but it's not insignificant and it's definitely not 0%.

Erik, note that I said "nearly unchanged" in my post.  That doesn't equate to 0%.    For the typical amateur the difference is insignificant because he just doesn't strike the ball sharply enough.

Quote:

Originally Posted by Fourputt 

Erik, note that I said "nearly unchanged" in my post.  That doesn't equate to 0%.    For the typical amateur the difference is insignificant because he just doesn't strike the ball sharply enough.

Sure, but you also said "You are mistaken in thinking that spin is applied by the grooves gripping the ball." A good chunk of spin is applied due to the corners of the grooves. :-) Might even be more than 10%. I don't have the study readily available... someone could look it up, though. It's more than what I'd call "insignificant" though, that's for sure.

if you watch Seans video, you can clearly see that the ball is already rotating before it leaves the clubs face.  Thats all that matters..grooves or face causing spin, it doesn't matter(in terms of this post)...what matters is that it does climb/roll up/move up the face of the club due to the loft and path of impact and what not.  Spin HAS to start at impact, else a golf ball would always have zero spin.

Quote:

Originally Posted by Fourputt 

You are mistaken in thinking that spin is applied by the grooves gripping the ball.  Backspin is applied by the friction between the ball and the clubface.  Spin is nearly unchanged on a clean hit with a club which has no grooves at all.  This has been proved through testing several times by different agencies.  The grooves only assist in creating more friction by channeling grass and debris away from the contact area when the lie is less than perfect.

The square grooves of Ping, when they first came out were producing hair balls, cutting out slivers of skin, with every stroke of the iron, making the balls useless after about 3 holes. It became necessary for Karsten to reduce the aggressiveness of his grooves by rounding off the edges, as shown in the Eye 2 or his clubs would not have sold. This can be looked up if there is doubt. However you can also see the evidence of the groove's activity in modern day wedges that are produced with very aggressive grooves. They scratch the balls excessively when new and some, far longer after than their owners like. A lot of those overly aggressive groove clubs find their way to the second hand racks quickly.

Until the edges of the grooves are softened, they take too much of a grip on the ball skin and produce backspin but at too high a cost. I believe this supports the grooves/spin argument.

The idea of the surface producing friction and therefore backspin, is seemingly also valid  when coupled with compression. However you can see how little that surface adhesion contributes by shaving a tennis ball and trying to play with that resultant smooth ball. You're not going to get a lot of reaction from it and will probably become tired more quickly. You might also surmise that the dimples on a golf ball help the ball grip the air a little better and therefore fly a bit farther. Smooth golf balls don't fly very well.

Shambles

Quote:

Originally Posted by LBlack14 

I've come to the find Lee Trevino to be full of sh*t. I've also found from old guys that work at a local course here where the PGA and Senior PGA held an event that he may have been one of the biggest a-holes on any tour EVER.

Which, of course, has absolutely nothing to do with this thread.  I guess if you grew up poor, and had to hustle your way to make a living, and were shunned just because of your background, you would be a standup guy. Unless you have lived his life, you don't really know.

Quote:

Originally Posted by Harmonious 

Quote:

Originally Posted by LBlack14 

I've come to the find Lee Trevino to be full of sh*t. I've also found from old guys that work at a local course here where the PGA and Senior PGA held an event that he may have been one of the biggest a-holes on any tour EVER.

Which, of course, has absolutely nothing to do with this thread.  I guess if you grew up poor, and had to hustle your way to make a living, and were shunned just because of your background, you would be a standup guy. Unless you have lived his life, you don't really know.

It all ties together. If you live through a lightning strike that produces positive "backspin" so you end up just a good old boy who's a bit misunderstood because of his hustlin' background. Then when you get older and weirder people apply negative "backspin". People come out of the woodwork and say you've always been a total ____.

The moral of the story is to maximize positive backspin you need to actually get killed by the lighting bolt, plane crash, or in Bubba Watson's case falling off that big tower.

This reminds of a Sam Snead story -

An amateur once asked Sam how to put backspin on a ball. Sam asked the guy how far he hit a 5-iron. The amateur said 'About 120 yards.'

To which Sam replied 'So why in the hell do you want it to back up?'