Of Fistmele and Brace Height

I got back into the swing of practicing some archery rather than just coaching it. I get huge satisfaction from being able to shoot, but this last week has been a real puzzle… until today. My arrows were banging into the arrow rest on their way out of the bow, and they were landing on the target with their fletches way off to the right. Hmmm, thought I, what could be the matter with this situation? Perhaps some tuning is in order? Yes indeed.

Some quick measurements: I have a Helix by Hoyt. It’s the long riser and long limb combination which makes a 70” bow. Let’s ignore the fact that a 70” bow isn’t really at all 70” long when strung. The measure is actually done with the bow unstrung. Yeah – we’re odd that way.

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The brace height (fistmele) was shy by almost 1 1/2 inch. The tiller was exactly the opposite of what it needed to be. With the Helix a typical tiller would be 0” difference between top and bottom limb, and up to about 3/8” LESS on the bottom than the top. The goal here is to have the limbs balanced just right, so that aiming is easier (pressure on the fingers equals out) and the bow shoots quietly. Brace height is much the same: adjust it such that the bow is most quiet. So…

I added about 50 twists to the string to increase the brace height to the low end of the range. I then tweaked the tiller with allen wrenches until I got the useful 3/8” less on bottom than on top. Results: a MUCH QUIETER BOW with arrows that fly straight and land straight. Wow – and I didn’t even have to mess with the plunger button.

About johnb

– Director of Grainger Observatory, Phillips Exeter Academy.
– Variable-star-crazed astronomer, but have done research in other areas.
– Drummer, archer, pilot, chef, friend, pet owner, husband, father, Train-nut.

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