Static bow balance- compensate for recurve sight window

[King Custard]

Just for the exercise I set up my Recuve bow and hung it from the ceiling fan to discover it's center of gravity.
Tied and hanging from a point one inch along the v-bar extender- the bow has perfect balance with the string running vertically.

Tied and hanging from a point corresponding to the center of my hand's pressure point on the grip...again perfect balance string horizontal and only a little 'tilt' as the sight is moved for different distances

Statically- all very good yes?

OK- but that's not good enough. What about balancing the bow to compensate for the off center sight window and sight weight???
Hanging again from the pivot point I have no weight on the sight-side short rod...and what seems a lot on the arrow-side siderod - just to drag the bow over enough that the string just meets the suspension cord from the ceiling.

So, at least statically this should be the best arrangement to resist any torque induced by the riser's offset window and the weight of the sight at release.
Long range shooting and grouping seems to have improved some small amount so I'm happy with the arrangement- even if it is only effected by my belief that it works.

BUT..
Why doesn't ANYBODY Else's short rod weight distribution look like mine?
Is it an oversight on the part of nearly every archer...? (Or do you balance like this too?)

Or just an unecessary indulgence on my part as any torque created by the riser itself has no effect on arrow direction...and therefore balancing in this plane has little or no effect? Could it be a bad thing to balance on this plane too, as the compounders do?
I'm thinking that it Should aid the bow to jump Directly towards the target on release and improve the swing/roll of the bow.
Or maybe im overthinking things and the offset window and sight really make no difference to the riser motion atall..

What do you reckon, and can you back it up from your experiences?

[JohnKR]

I did similar exercise with my bow, but perhaps not as accurate. For the side ways balance, I just hung the bow from my finger by the string and looked at the angle of the longrod. To “almost” level it up I needed to add just one extra weight to the window side shortrod end. How much extra weight do you use?
As for performance difference, well to be honest, I am not consistent enough to notice one way or the other. Like you say it may be just the belief that it works, and if it is that’s enough reason to do it.
On a related note, I am always surprised that people pay big premiums for carbon sight arms to save a few grams, when it pales into insignificance when you consider the extra weight on the sight side of the bow due to the sight window. I know it is an overall weight saving but unless the weight is of paramount importance it just seams over kill. But, if you believe it works.

[rod]

shoot the bow, see how it reacts

[King Custard]

Hi John, I'm using 3oz @ 9 inches from the bows centerline on the left siderod and nothing on the right siderod to balance nicely and I've checked and rechecked that the bow is suspended from the center of the grip/riser/limb.

Yes one weight ( 1&1/2 oz) did most of the balancing out- about 70% of it from memory, the second weight added balanced out the other 30%ish.

I agree with your thoughts on carbon shortrods, they don't really give you very much weight saving to reapply elsewhere

Hi Rod- I've shot the bow a few times now and grouping has improved marginally, though I admit I'm far from as consistent as I'd like....and bow roll is a little smoother and more consistent too.

I'm happy to shoot with what looks like a lop-sided bow stabilizer system- if it continues to give these better reactions anyway.

My only wish is that I were far more skilled and consistent MB or GMB- so as to prove or disprove that the sight and window should be 'moment compensated' for.
In the absence of someone of that class having tried it out fully, maybe we can get our resident physicists to promulgate a theory??

[moo-mop]

Originally Posted by King Custard

My only wish is that I were far more skilled and consistent MB or GMB- so as to prove or disprove that the sight and window should be 'moment compensated' for.

Neh, you wouldn't be able to prove it at all at this level. You'd need to be far better, I'm a great one for arguing most of what is said 'bout equipment and tuning is hearsay and not backed up cos variability from day to day is just too high, even if you can shoot a 1240ish relatively regularly.

However, I have been told by a 'senior coach' that you should balance the bow exactly as you say [edit: with reference to the sight window and lateral balance, not forward balance]... but I don't think I'll be trying it, as I shouldn't be changing things at the moment.

[Adam]

Originally Posted by King Custard

Hi John, I'm using 3oz @ 9 inches from the bows centerline on the left siderod and nothing on the right siderod...Yes one weight ( 1&1/2 oz) did most of the balancing out- about 70% of it from memory, the second weight added balanced out the other 30%ish.

You're sounding just like a compound archer now! Indeed, that's a very typical compound set-up.

Adam

[FlourPower]

sp220, I always heard it should be a little forward of the bow. Then again I don't use the things so....

[Chris B]

Originally Posted by King Custard

Statically- all very good yes?

"Static" when braced is not the same as static at full draw.
Firstly your limbs weigh around 300grams and move backwards a bit when drawing, so a "static" CoM at full draw would require a slightly foward CoM when at the brace height.

Originally Posted by JohnKR

On a related note, I am always surprised that people pay big premiums for carbon sight arms to save a few grams, when it pales into insignificance when you consider the extra weight on the sight side of the bow due to the sight window. I know it is an overall weight saving but unless the weight is of paramount importance it just seams over kill. But, if you believe it works.

The carbon-ness may be there to stop it shaking to pieces. When i needed a new sight, i chose the Shibuya Ultima, because i had recently seen 4 Sure-locs, a Toxonics 'something-or-other', and a Naildriver (all aluminium extensions) drop off their owners bows onto the floor, after their screws had shaken loose, from vibrating badly. Watch the youtube slow-mo video of aussie David Barnes (pulling ~56#) to see how much an aluminium sight wobbles when you shoot. (If you cant be *rsed, i'll just save you time; it wobbles s**t-loads!!)

Back on topic; here's my take on the Centre of Mass thing:
In the interests of Moment of Inertia, the CoM will be best placed away from the pressure point. If the CoM is at the pressure point at full draw, the bow will be very easy to torque.
When you draw the bow, you create a line of force that goes roughly between the nock and the pressure point in the grip. The forward extension of this is the line the bow wants to jump along when you release. The CoM should be forward of the bow on an extension of this theoretical line. If so, there will be no perpendicular distance between the CoM & the line of force felt by the bow upon release, so the bow will not torque or rotate, until it is caught by your sling (then it swings). So, before boredom kills even me, I'll just sum up by saying, buy a long extender!

Chris

[BorderBows]

What is it your trying to cure?

What is the effect your seeing that needs fixing, and is what your changing going to affect the effect. (not sure about the english in that one, but it makes my question easer to see)

nothing like extream ranges to highlight any effects?

[Hidden Hippo]

Originally Posted by sp220

I wish they made longer extenders.

As it is ive had to make do with a 5 inch extender with an extra v bar bolt screwed into the end to make it nearly an inch longer.

wish W&W made a 6"-7" though

Soma have just released a 6" CEX2 extender. From what I've heard about their rods it should be pretty decent. I'm sure I heard that Frangilli had a 6" HMC stabiliser, although that may have been a special order item just for him.