Does High brace height stress bow?

[bagada]

I was under the assumption that someone with a long draw should use a lower brace then recommended. However, on my 60 inch sage one piece, It seems to shoot best at 8 1/2 inches braced. Since my draw is nearly 32 inches, Am I stressing the bow by bracing it this high? My last bow broke in 11 days. I just want to be cautious. Thanks

[katman]

What is the recommended brace height on that bow and can you scale its weight it at 28,29,30, 31 and 32" draw?

[The Whittler]

I would say no different then leaving them strung.

[bagada]

I don't have a way to scale but Its recommended brace is 7 1/2 to 8 1/2. It's affecting my tuning to be worried about the high brace breaking my bow.

[Caughtandhobble]

I can't answer your question but I will recommend trading in your Sage for Journey due to your long draw length.


   

[stagetek]

If you're breaking bows, it's not because of too high a brace height. Having a 32" draw is the culprit. Get a longer bow. If you really have a 32" draw, I would shoot nothing shorter than 64" and 66" would be a better choice.

[bagada]

I ended up going to a super low brace height at 6 1/2 inches. Its even more quiet then the high 8 1/2. It feels smoother to pull and I get less string slap oddly. This tuning thing is funny that the "sweet spots" are at total opposite extremes.

I do plan to eventually get a longer bow. Well Im actually thinking of a big jim's thunderchild in 60 if he makes it. The design should allow me to shoot it at 32 inch draw. Thanks for the help guys

[Stumpkiller]

I shoot with as low a brace height as I can get away with before the bow gets too noisy. My draw is just under 30" and I shoot a 31-1/2" arrow.  Usually ends up around 7-1/4" to 7-1/2".

[bagada]

I tested my bow weight on a luggage scale. Drawing the string to the same spot as my anchor with the scale the highest reading was 44lbs. The bow has 40 written on the side. So 40lb at 28inches. 44lbs at 32 inches. I guess the bow is ok for longer draws. Yes i was even trying to draw past my normal anchor and the highest it read was 44lbs. I also tested the accuracy of the scale by weighing a 5 gallon water jug with a electric body weight scale then with the luggage scale. IT was dead accurate. I think the reason Im getting such low readings was the super low brace height, thus lengthening the string, and lowering the actual poundage.

[die_dunkelheit]

The way brace height affects the life of a bow is commonly misunderstood, but it is fairly simple.

Consider a bow that is unstrung. The limbs have zero potential energy in this state.
Now consider a bow that is braced. You had to put work into it to string it, right? Now there is potential energy stored in the limbs. The amplitude of that potential energy can be felt in the tension of the string. If you brace it higher the potential energy goes up, and bracing lower makes it go down. The initial string tension scales with the potential energy stored in the limbs at a given brace height. The thing to understand here is that potential energy is ONLY zero when unstrung.

Now consider a bow released from full draw. As the string resets to the brace height the limbs move forward toward their original unstrung position but are stopped short by the string. Energy equal to the potential energy stored at brace is exerted into the string, some of that energy is used up when the string stretches (here the string is acting like a shock absorber) but the rest of it travels as a wave from the string grooves and the string loops in toward the center of the bow and string respectively. String vibration is a result of wave interference when those waves collide in the string. Hand shock is partially a result of the same but in the riser (in addition to some other mechanical causes of hand shock if the point at which these waves meet is in the grip, and/or their magnitude is high enough, it will cause hand shock).

The waves traveling down the limbs, and the subsequent vibration stress the material bonds in the bow (think modulus of elasticity). Past a certain extent it starts breaking them, once too many of those bonds are broken the bow breaks.

Conclusion? The higher your brace height, past a certain extent, the more damage you do to your bow because the magnitude of the wave goes up.

So no, lowering your brace height won't hurt it.


Another way to think of what you are doing by lowering your brace height is that the limbs are actually not being pulled as far back when drawn because the string is longer,

[Crooked Stic]

Gaining 2 lbs. an in. would be considered smooth and should not be a problem. When the bow starts to stack is when the stress also starts. The brace heights you had here will not stress your bow.
A constantly over drawn bow will fail way before one with a too high brace height.

[nineworlds9]

Bagada,
you and the other fellas have it pretty well figured out, but I do feel you need a longer bow.  I am betting the string angle a the tips on that 60" bow is at or past 90 degrees, meaning youre losing efficiency anyway.  This has to do with how the limbs act as a lever when the string pulls on them.  Anything past 90 degrees at the tips is you pulling and the bow not doing anything else to help you launch that arrow.  That particular model bow is not really designed to shoot well past 29-30".  If you stick with a conventional recurve I highly recommend you get at least a 64".  Pull out a chrono.  The longer bow at your draw will cast the arrow farther and faster at a given distance because it's more efficiently transferring the energy.  

As for more radical bows designs and desiring a shorter bow for hunting, there are a number of custom bowyers who cater to the long draw short bow crowd.  Check out Java Man Archery and Big Jim for some great choices.

[nineworlds9]

Bagada,
you and the other fellas have it pretty well figured out, but I do feel you need a longer bow.  I am betting the string angle a the tips on that 60" bow is at or past 90 degrees, meaning youre losing efficiency anyway.  This has to do with how the limbs act as a lever when the string pulls on them.  Anything past 90 degrees at the tips is you pulling and the bow not doing anything else to help you launch that arrow.  That particular model bow is not really designed to shoot well past 29-30".  6.5" brace on that model bow is basically just a cheat to force it to work for you, but its obvious if its only gaining 4# from 28-32 that you're losing potential.  8#-12# over 4" would be much more standard and would give you more power. If you stick with a conventional recurve I highly recommend you get at least a 64".  Pull out a chrono.  The longer bow at your draw will cast the arrow farther and faster at a given distance because it's more efficiently transferring the energy.  

As for more radical bow designs, and desiring a shorter bow for hunting, there are a number of custom bowyers who cater to the long draw/ short bow crowd.  Check out Java Man Archery and Big Jim for some great choices.

[Orion]

A small difference in brace height isn't going to make much difference.  Sure, bracing it a little higher puts a little more pre stress on the limbs, but generally not enough to worry about.  

Your long draw, on the other hand, puts a lot of stress on the limbs.  Long draw length and short bow is not a good combination, and usually results in the bow's failure.  For a 32-inch draw, you would be much better off with a 64- or 66-inch recurve.

If you continue to shoot relatively short (for your draw length) bows, you can expect to continue to break them. Modern designs, materials and glues have ameliorated this problem somewhat, but bows are not indestructible.

[die_dunkelheit]

To be clear, what I described about how higher brace heights can damage the bow I was NOT talking about raising it 1/2 an inch or so but still within the suggested brace height range or slightly over or under it. What I was trying to do is explain HOW brace height "... Past a certain extent..." causes damage because to me understanding the how & why of something is the key to actually learning it.

[The Whittler]

I did watch a video where it was mentioned if the limbs are too short for a long draw, the long draw will break the limbs eventually.