# ATA and brace height??



## 138104 (May 14, 2009)

coyotekillin said:


> My ATA in perfect. But my brace height is off a 1/4 inch. Increase and decrease brace height. Is increase making my brace height shorter or longer. Im also only pulling 66# on a 70# bow. Thanks


Increasing your brace will reduce your ATA. Are the limbs bottomed out? If they are, I'd put 3 twists in each cable to get the dw up. Then, check dw and dl and get them in spec. Let the ATA and BH measurements end up where they end up. Also, keep in mind that ATA and BH specs are +/- 1/8".


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## nuts&bolts (Mar 25, 2005)

coyotekillin said:


> My ATA in perfect. But my brace height is off a 1/4 inch. Increase and decrease brace height. Is increase making my brace height shorter or longer. Im also only pulling 66# on a 70# bow. Thanks


Throw away the tape measure. Using a Tape Measure to measure ATA is using a tape measure to guess at the draw weight. So, add twists to both cables, until you get a draw weight that makes you happy.
If you are not happy with 66# on a 70# bow, throw away the tape measure and just use the scale. Keep twisting the cables, until you get a draw weight that makes you happy. Are you happy with 67#? Then, when you reach 67#, stop twisting the cables. ARe you happy with 69#? When you reach 69#, then, stop twisting both cables. Are you happy with 70# on the scale? When you reach 70#, then, stop twisting the scale. Want 71#? Then, when you reach 71#, stop twisting both cables.


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## nuts&bolts (Mar 25, 2005)

coyotekillin said:


> My ATA in perfect. But my brace height is off a 1/4 inch. Increase and decrease brace height. Is increase making my brace height shorter or longer. Im also only pulling 66# on a 70# bow. Thanks


But my brace height is out of whack. Throw away the tape measure. Brace height is using a tape measure to GUESS your holding weight at full draw. So, use a scale to measure holding weight. If you have 80% letoff, that means you want the holding weight at 20% of whatever you measure for draw weight. Let's ASSUME you twisted both cables and now the bow delivers 70# on the dot. So, you SHOULD get 14 lbs (20% of 70#), at full draw. BUT, you get 18 lbs of holding weight at full draw. Holding weight is too high. So, now what?

When holding weight is TOO HIGH, you untwist the bowstring.
When holding weight is TOO LOW, you add twists to the bowstring.

When the valley FEELS short, remove twists from the bowstring. Confirm holding weight with a scale...don't go by just FEEL.
When the valley feels TOO LONG, ADD twists to the bowstring. Confirm holding weight with a scale...don't go by just FEEL.


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## nuts&bolts (Mar 25, 2005)

coyotekillin said:


> My ATA in perfect. But my brace height is off a 1/4 inch. Increase and decrease brace height. Is increase making my brace height shorter or longer. Im also only pulling 66# on a 70# bow. Thanks


When aTA is "perfect" and the draw weight is too low, the bowstring is too short....cuz when you SHORT a bowstring, the draw weight drops.
So, remove twists from the bowstring, and the ATA stays basically the same, cuz the cams rotate away from the riser, as you remove more and more twists.
As you remove more and more twists from the bowstring, the draw weight will CLIMB higher. REMOVE twists from BOTH ends of the bowstring, to keep at ZERO peep rotation.


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