June 19, 2013
Do Longer Brace Heights Make Bows More Forgiving?
By Dave Hurteau
So how do you pick the perfect compound bow for your hunting? Two ways actually: You can turn to page 54 in the July issue of Field & Stream and read “Your Ultimate Bow,” in which Scott Bestul, Will Brantley, and I put seven key assumptions to the test in order to answer the most vital questions about what really makes the best hunting bow. Or you can just stay tuned right here, as we roll out the whole story, one question at a time, over the next few weeks.
Already saw it in the mag? Stay tuned anyway, because this online version fearures special bonus coverage, breaking down the inside story and the nitty gritty of each test.
You may think you know what you want in your next compound bow. But you’re probably wrong. (Don’t take it personally. We were wrong, too.) If you want a forgiving bow, for example, you know that you need one with a long brace height, right? Say, 7 inches. That’s common knowledge. And yet, the 540 arrows we shot to test this particular wisdom showed that brace height doesn’t make a bit of difference.
As for accessories, everybody knows that a Whisker Biscuit rest is not as accurate as a fallaway. Except, at the ranges most of us shoot, our tests proved that it is.
Bowhunters are gearheads. We want the ultimate bow, with the ultimate components, for the ultimate performance. And to that end, we apply a bundle of assumptions: This is better than that, and that is better than this, and the other is just no good at all. Yet it seems nobody has bothered to quantify any of it.
So we did.
We launched more than 10,000 arrows to nail down what really works. Not theoretically or in a laboratory—but for flesh-and-blood bowhunters in the field. Here's our first test and the results.
The Conventional Wisdom
A longer brace height (BH) makes a bow more forgiving of shooter error. BH is the greatest distance between the bow’s grip and the string. The purported reason why longer is better is that the arrow remains on the string for a shorter distance and period of time and is therefore less affected by your screwups during the shot.
But Wait a Minute
Watching slow-motion video of myself shooting, it looked obvious that the arrow was gone before I could twitch a muscle. Later, a bow engineer hinted to me that BH doesn’t matter with today’s fast bows.
We shot bows of the same make and specs, except for BH. I shot the Bear Motive 6 (6-inch BH) and Motive 7 (7); Bestul, the McPherson Monster MR5 (5) and MR7 (7); Brantley, the Hoyt Spyder Turbo (6) and Spyder 34 (63⁄4).
Average Grouping Results:
30 Yards: Short Brace Height: 2.83; Long Brace Height: 3.08
40 Yards: Short Brace Height: 4.16; Long Brace Height: 4.40
60 Yards: Short Brace Height: 6.31; Long Brace Height: 6.30
The answer is no. Not one of us found more than a lick of difference in accuracy or forgiveness. Brantley and I actually shot the shorter-BH bow slightly better, Bestul the longer—but neither appreciably. We all found that a longer BH made for a slightly easier draw cycle.
The Inside Story:
A couple of years ago, we shot this ultra-slow-motion video. Have a look (but ignore the voiceover) and you’ll see that even with the older bow and especially with the newer, the arrow is long, long gone before I can even twitch a nerve let alone grab at the bow’s handle or drop my bow arm—which suggests that it doesn’t really matter how long the arrow is on the string, which means BH shouldn’t really affect forgiveness. After seeing this, I talked to a couple of bow engineers, one of whom hinted at the same conclusion and the other flat out confirmed our suspicions.
This absolutely flew in the face of what we’ve been told for years about BH. Of course, we had to test it.
Brantley went first at his home in Kentucky and got these average groups for short BH, long BH:
30 Yards: 2.34; 2.72
40 Yards: 3.45; 4.27
60 Yards: 6.01; 7.00
Afterward he called me up and said (I’m paraphrasing here), “I’ll be damned; I shot the short-BH bow better.” I went next here at home and also shot slightly better, on the whole, with the short-BH bow; again average groups for short BH and long BH below:
30 Yards: 2.56; 3.02
40 Yards: 3.42; 3.64
60 Yards: 5.42; 5.45
Finally, Bestul shot at his home in Minnesota and did just ever so slightly better with the longer-BH bow:
30 yards: 3.6; 3.5
40 yards: 5.6; 5.3
60 yards: 7.5; 6.45
The average scores (above) sealed it: BH doesn’t make a significant difference, even at longer ranges.
It was this question that inspired all the others and led us to take on the larger project. If everyone could be so misguided about brace height, what other conventional wisdom might be dead wrong? So, we worked up a list of questions and started shooting and shooting and shooting, eventually meeting on Brantley’s farm in KY to shoot some more and evaluate our results. Stay tuned to see what else we found out about convetional bow wisdom.
How We Tested
Except where noted, all bows were equipped with a Trophy Ridge Whisker Buscuit rest and Cypher 5 sight and evaluated as follows:
For each configuration (short brace height, long brace height, stabilizer, no stabilizer), Bestul, Brantley, and I each took 10 three-shot groups at 30, 40, and 60 yards, eliminating the worst group in each set and averaging the remaining nine. For the final number, we averaged our individual results. Whenever possible, when comparing A to B, we alternated (A then B, then B then A) during the shooting session to preclude fatigue as a factor.
More Test Results to Come:
#2: Does a Short Bow Hamper Field Accuracy?
#3: Is a Single Small Sight Pin More Accurate?
#4: Does a Fallaway Rest Out-Shoot a Whisker Biscuit?
#5: Does a Short Stabilizer Really Add Stability?
#6: Does Too Long a Draw Length Hurt Your Shooting?
#7: Does Removing a Bow's Grip Improve Accuracy?