# How to measure brace height?



## Rogier (Aug 11, 2013)

Hi,

I am confused about where to measure the brace height of my olympic recurve bow.
Can someone please tell me to what location on the raiser I should measure the distance from the string?
Also I would like to know where the string needs to sit against the bow square. Against the aluminum or inside the rounded openings in the clamps?

Thanks in advance for your advise.

Rogier


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## chrstphr (Nov 23, 2005)

point c to string. put T square in grip at point C horizontally and use ruler on tsquare to measure string. 


View attachment 1733541



and string in the indents of the clamps if using T square as you have it. 


Chris


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## Rogier (Aug 11, 2013)

Hi Chris,

Thanks for the quick reply.

I just checked the square with a ruler and found that the the distance matches up with the string against the back of the square. Apposed to the string inside the indent in the clamps. Where it measures 0.25" to long...


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## Rogier (Aug 11, 2013)

Now I have a new problem.

The distance I measure is 9.25 " and can only make it longer if I twist the string.
According to my knowledge the distance should be 8.25 - 8.75"


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## chrstphr (Nov 23, 2005)

brace height is different for each bow / limbs. My bow recommended range from the manufacturer is 22-24cm (9.1 to 9.4 inches). For bows i have owned, my brace height has always been 9.25 to 9.5, but that is my bow manufacturer's recommendation. Yours may be different. You may shoot a brace height from 8.0 inches to 9.5. There are no hard or fast rules. 

What does Win Win recommend for your brace height? How does the bow sound when shot? 


Chris


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## HikerDave (Jan 1, 2011)

Rogier said:


> Now I have a new problem.
> 
> The distance I measure is 9.25 " and can only make it longer if I twist the string.
> According to my knowledge the distance should be 8.25 - 8.75"


If you've already taken most of the twists out of your string then your only choice is to get a slightly longer string. Your bow will tolerate a higher brace height such as the one you have if you loosen the tiller bolts to decrease the weight of the bow. But you probably shouldn't worry too much about this right now -- just shoot the bow and after a while the string will lengthen slightly.


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## Viper1 (Aug 21, 2003)

Rogier -

For general purposes. string to "C" is the correct measurement.
However string to "A" (which I assume is the the center of the rear plunger hole) should equal string to "C". 

Most 68" bows will brace in the 8.5" - 9" range and most 70" bows 9" - 9.5" range, but that isn't carved in stone. 
Brace height is a tuning parameter, not an absolute.

Viper1 out.


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## Rogier (Aug 11, 2013)

Thanks Viper 

Indeed C and A are at equal distance where A (plunger) is more accurate to measure using the bow square.

Now here is a follow-up question. How does one detemine the bow length?
I have been told its 68" but how does one measure it? Strung or unstrung across the length of the string.
Or really odd; the total curve length of the bow..


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## dchan (Jun 29, 2004)

HikerDave said:


> If you've already taken most of the twists out of your string then your only choice is to get a slightly longer string. Your bow will tolerate a higher brace height such as the one you have if you loosen the tiller bolts to decrease the weight of the bow. But you probably shouldn't worry too much about this right now -- just shoot the bow and after a while the string will lengthen slightly.


And until you are shooting at a level that really matters, it's still not worth "worrying" about. A level like ends of 27/30 at 18M 40cm targets. It is very important you know that that brace height is and set your bow to the same every time, so you know if something is moving but if it's consistent, I wouldn't even worry about it.

While BH is an important part of fine tuning a bow, As Viper1 states, it's not an absolute. you tune the brace height to match several other things including the archer and how much they deflect the string with their fingers. The MFG just gives you a range to start in. A .5-1" range is huge. sometimes as little as 1 twist can make a big in the tune. So get close, then go shoot.


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## dchan (Jun 29, 2004)

Rogier said:


> Thanks Viper
> 
> Indeed C and A are at equal distance where A (plunger) is more accurate to measure using the bow square.
> 
> ...


Technically it's supposed to be the total curve length of the bow but if you measure that along the face and then along the back you would come up with different information.

real world, we go by what MFG puts on the bow/riser. AMO has "standards" (now ATA) that most bow makers conform to.

MOST Limbs come in 3 lengths. Short, medium, long
MOST risers come in specific lengths. 17", 21", 23", 25", 27"
Sky makes I believe a 24" riser.
Short limbs on a 25" riser = 66" bow.
If your limbs are labeled 25H 68-26lbs (25" handle/riser) then you have medium limbs. 

Most MFG's list 23" and 25" riser info. 

DC


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## Viper1 (Aug 21, 2003)

Rogier - 

Here's the technical but almost useless answer (according to the AMO): 



> AMO/ATA bow length is defined as 3” longer than a bowstring made to a given length, based on an AMO/ATA Bowstring Master.
> 
> For example, a 63” string matching an AMO Bowstring Master will be designated as AMO 66” string and yield the bowyer’s recommended brace height for an AMO 66” bow.


Do all manufactures follow AMO specs? Well, no. 

For practical purposes, use dcan's description or this variation.

25" riser + long limbs = 70"; + medium limbs = 68"; + short limbs = 66". 
Add or subtract 2" of overall length for every 2" change of riser length.

Viper1 out.


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## Rogier (Aug 11, 2013)

Thanks for all your help :thumbs_up:thumbs_up:thumbs_up

I went back to the range, took my time. Un twisted the sting.
Brace hight (to point A) at the start was 8.75" and after 90 minute and +/- 120 arrows ended up on 8.50"
Even with tired arms / shoulders I ended after an hour and a half up with this.
Can't complain :smile:


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## dchan (Jun 29, 2004)

Nice group.

Don't untwist too much. you need some twists to keep the string together.. If you completely untwist the string it will not stay in a bundle when you shoot.

How many twists?
The BCY website states this
===================================
Question: How many twists can be put into a bowstring?
Answer: There are three reasons for twisting a bowstring -
1. To keep the bundle of strands together
2. To shorten the string after creep has occurred (adjust draw length)
3. To correct peep rotation

On a standard compound bow, initially .5 to .75 twists per inch is a suggested range; meaning on a 60" string, you should apply 30 to 45 twists. If you use a material that does not creep, no further twisting will be required. Obviously on single cam strings, more twists may be required because the string is longer. We have found that a higher twist level reduces peep rotation.

=======================

Recurves don't use peeps and the information states compound bow, but the principle still applies. need some twist to keep the bundle together. .5 to .75 is about right as a starting point. Some people prefer less, some more but you need some.

DC


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