Trad Gang
Main Boards => PowWow => Topic started by: Pivo on April 05, 2015, 10:32:00 AM
-
Why does a tuning guide say to lower brace height if your arrows are slightly weak. This seams backwards to me. doesn't a bow put more power to the arrow the lower the brace is? More "power stroke"? I know it's probably right but I can't wrap my head around it.
-
I'm curious about this too. I'm thinking that lowering the brace height will hold the rear of the arrow in line with the center line of the bow for a longer period of time. Raising the brace height will release the arrow sooner, allowing the nock of the stiff arrow to move around the side plate sooner instead of bouncing off it?
-
Lowering the BH, in effect, moves the strike plate out stiffening the arrow.
-
Any time you lower brace height, you relieve tension on the limbs, effectively reducing poundage to a degree.
-
That's probably a factor too, but I've changed brace height and checked the draw weight at 28" and seen very little change - some, but not much for minor changes. Could be its a combination of several factors?
-
Bladepeek's first post got it right.
-
If you change your brace height by say 1", you are not changing the draw weight by 3-4lbs. So a higher brace is exerting roughly the same amount of energy over a shorter distance. Basically a stronger, but shorter push than with a lower brace. This coupled with the change in angle of the arrow shaft against the side plate can have an effect on the dynamic spine of the arrow.
-
BP's got it, and yes it does sound backwards, but I think of it this way....the longer the arrow stays on the string before nock release, the stiffer it will "act". It all has to do with the paradox of an early(high brace) versus late(low brace) release, but I honestly believe there is more inconsistency in the average archer's form release to release than you'll ever notice from this effect.
-
Yes, it's a function of the angle of the shaft against the side plate at brace, or end of power stroke.
-
Originally posted by Pivo:
Why does a tuning guide say to lower brace height if your arrows are slightly weak. This seams backwards to me. doesn't a bow put more power to the arrow the lower the brace is? More "power stroke"? I know it's probably right but I can't wrap my head around it.
The expression you hear about "Putting more power into the shaft with a longer power stroke" has much more to do with a 30" plus draw length vs 28" or less draw length.
Here's a fact about what changing brace height does to the energy transfer...... There is a sweet spot in every bow where the tension on the string at brace is the highest. THAT is where your best performance is going to be....It'a also where there will be the least vibration transferred to the grip. If you raise it higher or lower it you will loose efficiency.
Less energy going into the shaft is going to flex the shaft less and make it act stiffer. How much? Well that depends on your bow, and the design. Some bows won't show much difference in performance in a 1/2" brace difference at all. Other it will be more significant.
You will not see any difference in the draw weight at 28" or 30"..... What the brace height changes is the bows pre-load on the limbs and THAT determines the energy transfer level.....
For this reason it's always best to find the sweet spot in the brace, and tune the arrow spine to the bow. Using brace height for arrow tuning should be used as a last resort. IMO
btw.... if you are not getting good arrow clearance on bows cut before center, a lower brace will just make matters worse.