Guess How Much Golf Ball Spin Drops When You Hit a Wedge from the Rough Versus the Fairway
The answer to that question comes courtesy of a Bridgestone Golf patent that issued last week directed to a groove design that reduces the drop in spin when hitting from the rough. Since I am always in the fairway I can’t really relate to this problem, but I hear that it is an issue. Now, back to reality, the stair step groove design is found in USPN 
The patent goes on to explain:
As is obvious from FIG. 6, the example and Comparative Example 2 are different only in presence/absence of a stair-shaped portion. The example corresponds to a golf club head obtained by forming stair-shaped portions respectively in the flat portions 3211 of Comparative Example 2.
In FIG. 6, “Conformance to two-circle rule” indicates whether the golf club head conforms to the above-described two-circle rule. “NG” means “not conform” and “OK” means “conform”. Only Comparative Example 1 does not conform to the two-circle rule.
A test for the backspin amount was performed by hitting a plurality of golf balls with each of the golf clubs from the fairway and rough, and the backspin amount was actually measured. Of “test results” in FIG. 6, “backspin amount” shows the average values of the actually measured values of backspin amounts obtained from a plurality of shots from the fairway and rough. Letting BSf be the value shown in “backspin amount” in the case of a shot from the fairway and BSr be the value shown in “backspin amount” in case of a shot from the rough, “percentage of decrease” is calculated…
“Percentage of decrease” is an index indicating a degree of decrease in the backspin amount of a shot from the rough with respect to a shot from the fairway. The smaller the absolute value, the smaller a decrease in the backspin amount in the case of a shot from the rough.
From the test results, it is obvious that a decrease in the backspin amount in the case of a shot from the rough is small in the golf club head of the example. Particularly, since Comparative Example 2 and Example are different only in presence/absence of a stair-shaped portion, it is obvious that the stair-shaped portion has an effect of suppressing a significant decrease in the backspin amount of a shot in the case of a shot from the rough.
There you have it, a 65 to 70+ percent decrease in the amount of spin generated when hitting from the rough seems to be pretty standard. How much would you be willing to spend for a 3% improvement?
Dave Dawsey – Monitoring Golf Technology
PS – Check out other golf iron invention posts HERE