# Lie Angle

## What it is and Why we care

The lie angle of the club is the angle the shaft makes with the ground, when the club is in the proper address position with the grooves level. There is a de-facto or nominal "standard" lie angle for each iron. If a club has a higher lie angle than standard, it is called "upright"; if lower, it is called "flat". For instance, the normal lie angle for a 5-iron is 60 degrees. A 5-iron with a 58-degree lie would be called "two degrees flat". A player with a particular size and swing will require a particular lie angle in order for the clubface to be level at impact. And it is important for the clubface to be level at impact. The reason? The direction of the clubface at impact varies with lie angle. And it can vary even more if the ball is hit a little fat.

### Direction of clubface

The more toe-down the club, the more the clubface will face to the right (for a right-handed golfer; we'll use the right-handed convention from now on). The result will be a push, but the right-facing clubface will also impart some slice spin that will magnify the effect.

The figure should help you visualize this. Take a well-lofted club (a short iron) and hold it with the shaft perfectly vertical. This will simulate a seriously exaggerated too-flat club (i.e., toe-down) for the very upright position in which you're holding it. Notice how the face is pointing not just up, but well to the right as well.

Conversely, if you hold the shaft horizontal, the clubhead is toe-up, or "upright". And the face points well to the left.

By the way, this is the same reason that a sidehill lie with the ball below your feet is a "slice lie" and with the ball above your feet is a "hook lie". With the ball below your feet, the shaft will be more vertical than the design of the club; with the ball above your feet, it will be more horizontal.

How much of a directional error will you get from an error in lie angle? The greater the loft, the greater the angle of error. The formula controlling the directional error is actually pretty simple:

DirectionalError  =  Loft * sin( LieError )

If the loft is zero, then lie errors don't matter. (Well, they matter if you hit it fat. We'll see this in the next section.) If the lie error is zero, then there is no directional error. Here's a table of where the clubface points for various lofts and lie errors.

 Lie error Loft (degrees) 10 20 30 40 50 1 0.2 0.3 0.5 0.7 0.9 2 0.3 0.7 1.0 1.4 1.7 3 0.5 1.0 1.6 2.1 2.6 4 0.7 1.4 2.1 2.8 3.5 5 0.9 1.7 2.6 3.5 4.4 6 1.0 2.1 3.1 4.2 5.2

This says that the greater the loft, the greater the error. But that is the angular error; the error in yards is not so cut-and-dried. That's because the greater the loft, the less the distance -- so the angle of error doesn't matter as much in yards. Here is a table of total directional error (in yards) for a variety of clubs, due to each degree of lie error.

 Club Loft Distance (yards) Face Angle Error (degrees) Yards Error Driver 10 250 0.17 2.5 3-iron 20 190 0.35 2.8 6-iron 32 160 0.56 3.2 9-iron 44 130 0.77 2.8 Sand wedge 54 100 0.94 2.0

The table takes into account both the initial directional error and the slice due to the open clubface. I used a rule of thumb that I derived, multiplying the directional error by a "curvature factor" to include slice. The factor itself increases with distance, in opposition to the face angle error. So the yards of error reach a maximum for a six-iron. But all the irons have an error of roughtly 3 yards for every degree of lie angle error. That's not trivial; three yards, or 9 feet, can easily be a stroke difference for a good golfer -- the difference between a tap-in and a 10-foot putt. And that's just a one degree lie error.

### Twisting with Ground Contact

So far, we have been talking about directional errors with a good strike. Now let's discuss what happens if you hit it fat -- if the sole of the club hits the ground before the clubface reaches the ball. Yes, that will cut yards off the shot, but it will also exaggerate the directional error.

A club with the proper length and lie will, at the bottom of the swing where the club meets the ball, have the head perfectly level. An important consequence of this is that the club strikes the ground at a point directly under the sweet spot of the clubhead; this is also directly under the ball, assuming the golfer has managed to strike the ball on the sweet spot.

But what happens if the club is not the right lie? Let's consider the too-flat or too-short club, which is toe-down as it strikes the ball. The toe will strike the ground first, and twist the clubface open.

If you hit the ground before the ball (that is, hit it fat), this twisting of the clubface greatly multiplies the small directional error we had before due to the flat lie. Now you don't have a small push or slice; you could have a disastrous one. If the club is too long or has a too-upright lie, the opposite is true. The club will face left at impact, encouraging a pull or a hook. A fat hit will further close the clubface, giving a potentially disastrous pull or hook.