# stabilizer balancing



## machinegunjohn (Nov 29, 2010)

I was wondering how you guys balance your bows. I was told to hang it from a string and adjust my weights accordingly. I ask because i bought a posten 30" with 10" v bars, my bow seems to pull me down badly, always fighting it up, and it dont seem to help adding weights to the v bars? Think the 30 is too long?


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## nuts&bolts (Mar 25, 2005)

machinegunjohn said:


> I was wondering how you guys balance your bows. I was told to hang it from a string and adjust my weights accordingly. I ask because i bought a posten 30" with 10" v bars, my bow seems to pull me down badly, always fighting it up, and it dont seem to help adding weights to the v bars? Think the 30 is too long?


Hello machinegunjohn:

I recently did some stabilization experiments,
to answer the exact question you asked.

Seems that folks these days,
are liking the long front stabilizer
with
a single side stab on one side,
with a HUGE amount of weights.

http://www.archerytalk.com/vb/showthread.php?t=1393184&referrerid=22477

See post #8 for photos and the results of my experiments.















































Now,
the number of washers on the front of my old Posten stabilizer is mis-leading,
cuz this is a custom Posten with internal weights,
and extra long slots to get the FOC and the total weight to my specifications,
when I ordered this years ago.

So,
on the side stabilizer,
I built a home made off-set bar, but it could not hold the angle adjustment, 
cuz the side stab needed a TREMENDOUS amount of weight,
to get to a neutral balance (no tipping down and no tipping up, after the shot).

So, the homemade offset bar did not work,
and I went and purchased the Doinker Adjustable Offset Mount.

This thing works just great.
It has gear teeth on the top half 
and it has gear teeth on the bottom half,
so when you tighten down the screw
that holds the two halves together...

your angle setting is locked down perfectly.

I used threaded rod, and lots and lots of washers
to get my old Martin Razor X balanced.

I have large forearms,
so I just rotated the Doinker Adjustable Offset Mount
to get the side stabilzer as low as possible.

Then,
I would adjust the horizontal angle on the Doinker Mount,
to move the side stabilizer farther and farther away from the bowstring.

A little bit makes a very noticeable difference.

The goal for setting the horizontal angle of the side stabilizer,
is to help you with left and right misses.

A Right Hand shooter will sometimes torque the bow to the left.
Could be bow hand grip position.
Could be that your follow through on your release elbow is not exactly in line, behind the arrow.

So,
when you swing the side stabilzer farther and farther away from the bowstring,
the heavy side stabilizer will want to make the bow torque to the right (clockwise direction).

The goal
is to find the angle setting (move the Doinker Offset Mount one gear tooth at at time....for each experiment)
till you find the angle setting
that reduces your horizontal misses (left and right misses)
to the absolute minimum.


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## SonnyThomas (Sep 10, 2006)

Bfisher and I this morning spoke of stabilizers and people buying them first and asking afterwards. nuts&bolts just gave a good account of the trials to arrive at a well balanced bow.
The link below is some hard reading, but with pics and some thinking it gets the message across.

http://www.centenaryarchers.gil.com.au/images/Bow Stabilisation.pdf


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## asa1485 (Jan 16, 2008)

N&B pretty much covered it.

Doing this on a string will not help you. It has to be done while you are holding/shooting the bow. Everyone is different and wants a different feel so, it comes down to you.


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## Spikealot (May 27, 2009)

Sorry for the hijack - I understand the stab part but I'm confused about the cam rotation in the pics.


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## nuts&bolts (Mar 25, 2005)

Spikealot said:


> Sorry for the hijack - I understand the stab part but I'm confused about the cam rotation in the pics.


Ahhhh.

You noticed.

Another part of the stabilization experiment,
was to experiment with the following things:

a) how much side stabilizer weight to get the front stabilizer follow through reaction to be dead straight forward (no up or down)

b) how much total weight for the bow system could I handle, in order to hold steady better

*c) how could I keep the draw weight low (between 45 to 50 lbs) AND get near 50% let off percentage*

Answer to Experiment (c).....short string the bow ON PURPOSE.

Those are Martin Nitrous Cams (size B),
so I put the draw length module at maximum,
about 2-inches longer than my preferred draw length...
and
built a custom string extra short,
and then built cables to match (to get to my preferred draw weight).

So,
I have the best of both worlds.

Solid Wall. Comfy draw weight (about 46 lbs). Nearly 24 lbs of holding weight.

Draw is VERY SMOOTH.
Lots of speed and nearly zero valley.

Makes for a very crisp release, when shooting a BT hinge.


The higher your holding weight,
the more the mass of your bow system should be.

High Holding Weight and medium-ish draw weight
is the ideal system for a target bow.

So,
once you find the amount of side stabilizer weight
that balances out your front stab weight...

then,
you can add weight to both ends
or
you can take off weight on both ends

to match your holding weight.

Your scores will tell you if your bow system is too heavy.
On Monday this week, I just shot a Double Indoor FITA (240 arrows).
Took quite a while, but the long training session....

showed me what about my form works, and what about my form does not,
and
the x-count for the last 30 arrows of the 240,
also tells me a huge amount about my current stabilization system.

I have a new system coming in,
and will repeat the experiment.


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## Spikealot (May 27, 2009)

" I put the draw length module at maximum,
about 2-inches longer than my preferred draw length...
and
built a custom string extra short,
and then built cables to match (to get to my preferred draw weight).

So,
I have the best of both worlds.

Solid Wall. Comfy draw weight (about 46 lbs). Nearly 24 lbs of holding weight."


Did that put you at your preferred draw length?
... and what is the total weight?


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## bfisher (Nov 30, 2002)

Alan, I was also going to ask about the cam orientation. Your explanation sounded weird till I thought about it. My experience had always been with round wheel bows, like 30 years ago. I'm beginning to get back into indoor somewhat, and these 80% letoff bows just don't work well for that. I have a 2005 ShadowCat that needs standard limb pockets to make it Mag version and I might just play around with this idea. I'm presently shooting an Alien Z so maybe moving the module on that would be worth experimenting with. The draw stop is near perfect as is.

And just to clear up some terminology are the cams on your Razor considered advanced or retar.ed?


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## nuts&bolts (Mar 25, 2005)

Spikealot said:


> " I put the draw length module at maximum,
> about 2-inches longer than my preferred draw length...
> and
> built a custom string extra short,
> ...


Yes.

I put the draw length module to the last hole,
for maximum draw length,
and
then...

built a "short" string,
to get to my preferred draw length.

This is called "short-stringing" for obvious reasons.

The primary reason for "short stringing" is to reduce draw length.
The side effects are:

a) lower draw weight

and

b) higher holding weight.

I just remeasured everything.

43-44 lbs of draw weight (Viking spring scale).
20 lbs of holding weight.

53% letoff percentage.


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## nuts&bolts (Mar 25, 2005)

bfisher said:


> Alan, I was also going to ask about the cam orientation. Your explanation sounded weird till I thought about it. My experience had always been with round wheel bows, like 30 years ago. I'm beginning to get back into indoor somewhat, and these 80% letoff bows just don't work well for that. I have a 2005 ShadowCat that needs standard limb pockets to make it Mag version and I might just play around with this idea. I'm presently shooting an Alien Z so maybe moving the module on that would be worth experimenting with. The draw stop is near perfect as is.
> 
> And just to clear up some terminology are the cams on your Razor considered advanced or retar.ed?




I always get confused about the lingo as well.

If we were talking the draw stop,
and we see a gap,
between the draw stop and the cable,
we could say the cam is "******ed"
and we need to close the gap,
or "advance" the cam,
to close up the gap.

So,
I believe when we "advance" the cam,
we are rotating the cam towards the riser.

So,
I guess you would say I have advanced the cams,
quite a bit.

So,
whether the cams are "advanced" or "******ed"...

the short stringing method,
rotates the cams towards the riser,
as the string gets shorter and shorter.


This method also works on any cam with an aggressive draw cycle,
as long as you have modules to work with, and an adjustable draw stop.

Set the draw length module say 1/2-inch longer than normal,
and then move the draw stop to stop the rotation EARLY,
so that your draw length is correct. Holding weight goes up,
and draw weight drops slightly, and this smooths out
the draw cycle.


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## Spikealot (May 27, 2009)

Thank You Sir.
I am curious still - what is the total weight of that rig.?


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## fletched (May 10, 2006)

One thing to add about stabilizers is to test them out on the target and see if it is actually helping you. When you make changes to the weight or length, see if it actually helped you out or made things worse. It can take some time and it's trial and error. It's easy to get caught up in making your bow look professional but it needs to be a benefit to do the job as intended. Here is a long article that explains a few things. I copied it so I could post it for others to read.

Our BASE weight is designed for this very purpose. Todays bows are notorious for having a top/front heavy feel, which more and more archers are finding to be an annoyance and not conducive for "ease of aim" , balance, and overall stability.

The BASE lowers your bows center of gravity , provides unmatched performance on the forward and lateral axis , provides a shooter friendly neutral balance , and can be adjusted for overall weight and weight placement both laterally and vertically to aid in balancing your bows sight and quiver.

The BASE essentially transforms your bow into a plumb bob, always working to keep your bow level and plumb.

Please feel free to contact me, I will be more than happy to explain the science and virtues of our BASE system.


Here's a brief comparison of the BASE to a high FOC front mounted stabilizer.

Ounce for ounce, length for length (from the axis of rotation) or grip.

We can compare balance, leverage, rotational inertia, and their effects on the bows center of gravity. For practical purposes our test model will be a naked static bow, its center of gravity located at the grip axis with its stabilizer bushing mounted 5” below. 

Remember balance can be determined with leverage, which is calculated by weight times length, MOI is calculated by weight times the square of length. MOI of a uniform rod is calculated by weight times the square of half its length.

Our test stabilizers consisting of a 15 ounce BASE weight, and a 12 " long front mounted hunter class stab with a 12 ounce weight located on the distal end, adding its mounting rod it will have a total weight of 15 ounces matching that of the BASE.

Forward balance:

In practical terms adding a front stabilizer 12” in length with 12 ounces of distal weight and 3 ounces of rod will result in 153 ounces (12 X12) + ( 1.5X6)of leverage tilting your bow forward, not a good idea if you’re looking for anything close to a neutral balance. To overcome this forward balance you will need to add an equal amount of opposing leverage. You can accomplish this with an equal amount of weight placed an equal distance away, twice the weight at half the distance, half the weight at twice the distance and so on. Mounting the forward stabilizer in the mounting bushing located 5" below the grip axis will also have only a modest effect in lowering the bows center of gravity. 

Mounting a 15 ounce BASE unit 12” below the grip axis will enable the bow to keep its shooter friendly neutral balance, while also dramatically lowering the bows center of gravity, resulting in a much more stable aiming platform.

Advantage BASE


Lateral balance:

lets now add a sight and quiver to the bow….these items will once again add an undesired amount of leverage acting upon the neutral balance of the bow , generally tilting the bow laterally to the right (right hand shooter) and slightly forward off axis.

The BASE weights can now be adjusted and biased laterally to compensate for the lateral disturbance in balance from the quiver, and depending on the geometry of the riser they can also be mounted slightly back on the riser to help compensate for the disturbance in balance from a forward mounted sight.

The front mounted stabilizer with uniform disc has no specific ability to balance your bow laterally.

The BASE is clearly more effective in balancing your bow on both the forward and horizontal axes.

Advantage BASE


Center of Gravity :

We know the bows original center of gravity was located at the grip axis prior to adding the sight and quiver, however the bows center of gravity is now higher with the addition of weight above its center axis. For practical purposes we will assume the sight and quiver combo weigh a combined 24 ounces, their weight concentrated six inches above the grip axis for a total leverage of 144 ounces. (6X24)

We know the front stabilizer bushing is located five inches below the center of the grip axis, the front mount stabilizer weighing 15 ounces and attached five inches below the grip has a leverage force of 75 (15 X5).... dreadfully short of the 144 number needed to bring the bows center of gravity back to neutral at the grip.

The BASE weighing 15 ounces and mounted 12” below the grip combine to give a leverage of 180, (15 X12) overcoming the values of the sight and quiver and lowering the bows center of gravity to an area below the grip.The BASE can lower your bows center of gravity almost two and a half times further than the front mounted unit.

The BASE is much more effective in lowering your bows center of gravity to the grip axis and below, resulting in a much more shooter friendly, stable, and forgiving platform.

Advantage BASE


Resistance to torque: MOI

Lateral axis. ( tilt forward / back)

In practical terms the front stabilizer will have a MOI value of 2028 on this axis, this is due to the 12 ounce mass being located 12" away from the bow, and 5” below the grip. The effective tangential length to square is extended to 13………. 12 ounces X 13X13 =2028 MOI

The BASE will always out perform a traditional front mounted unit in this area, ounce for ounce, inch for inch...here's how:

We have a front mounted unit with a length of 12" and a 12 ounce weight located at the end, all mounted 5" below the grip axis at the stabilizer bushing. We MUST also include the full weight of the stabilizers attachment rod into the equation of 3 ounces for a total of 15 ounces.

In this case the front mounted stabilizer weighing 12 ounces will have a rotational resistance of 2028. 12X13X13 not including the moments from the mounting rod.

The BASE with a TOTAL weight of 15 ounces, mounted 12" below the grip axis will have a value of 2160. (15X12X12)

This or course does not factor in the modest amount of added torque resistance from the mounting rod, which equals approximately 108, however we added additional moments by assuming the front stabilizers 12 ounce weight is centered at 12", which is impossible for hunter class stabilizers, the actual distance may be closer to 11.75...which would more than negate the added moments of the rod.

A more accurate representation of the numeric values on this axis would be (12X12.75X12.75) + rod (3X6X6) for a total of 2058.


Advantage BASE


Vertical axis (left right torque)

Forward stabilizer has a value of 1836 (12 ounces X 12 X12) + rod (3X6X6)

BASE has a value of 60. (15 X2 X2) ...Weights concentrated 2" away from the riser.

Advantage front stabilizer.



Forward axis : ( left / right cant)

Forward stabilizer has a value of 375 , regardless of disc size (15 ounces X 5 X 5) 

BASE has a value of 2160. (15 ounces X 12 X12 )


Advantage BASE.

The BASE also has the advantage in rigidity by way of its mounting platform using the stiffest part of the bow, the riser.....most folks are also finding the BASE is much more effective at reducing vibration than its front mounted counterpart.


The BASE has the advantage its ability to aid in both forward and lateral balance, forward and lateral rotational resistance, center of gravity, efficient use of weight, versatility, and mounting rigidity. 

The front stabilizer has the advantage through the vertical axis only.



BASE concentrated 12" from grip axis.


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## nuts&bolts (Mar 25, 2005)

Spikealot said:


> Thank You Sir.
> I am curious still - what is the total weight of that rig.?



Martin Razor X with Sight and with Doinker Adjustable Offset Mount = 5 lbs.
Front stabilizer with weights and bowjax = 1 lb
Rear stabilizer with lots of fender washers = 2 lbs.

Total system weight = 8 lbs.


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## Spikealot (May 27, 2009)

nuts&bolts said:


> Martin Razor X with Sight and with Doinker Adjustable Offset Mount = 5 lbs.
> Front stabilizer with weights and bowjax = 1 lb
> Rear stabilizer with lots of fender washers = 2 lbs.
> 
> Total system weight = 8 lbs.


Cool :thumbs_up


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