# Single Cam String Help



## ND Swede (Feb 21, 2009)

Good question, hope it gets some good answers.


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## Don_Swazy (Jul 9, 2013)

Nothing huh?


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## hoytelement24c (Jun 4, 2013)

Go with both until ATA and peak draw weight are in spec!


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## Don_Swazy (Jul 9, 2013)

This isn't a matter of whether or not to get the bow into spec. Saying use both states nothing, but thanks anyway.

Get ATA with cable? Or get a long ATA with cable, then twist string to tighten and bring ATA into spec. Or does shooting string have no effect on ATA?


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## djorgensen3 (Jun 17, 2007)

He is saying "Both" because it takes the correct length string AND cable to get to the correct ATA. It isn't really one or the other. You CAN use one or the other to fine tune your particular draw length and cam rotation (within reason) however. Adjusting (twisting or untwisting) one or the other will have an affect on the ATA shorter or longer. The specs for a bow are guidelines that you should try to follow closely and if you have to stray too far from them, you probably need different string, cable and/or cam to get back closer to the bow specs.


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## nuts&bolts (Mar 25, 2005)

Don_Swazy said:


> With any single cam, do I strictly twist the cable to get ATA into spec or does twisting string come into play too?
> 
> For instance, do I want to leave ATA a little long with the cable then bring into spec with twisting the string? I'm assuming get the ATA into spec with the cable only.
> Thanks.


Single cam bow.

You have a two part rigging system.

When you UNDERSTAND how to fish,
then....it becomes MUCH more simple.

So,
let's start with the buss cable.

So,
let's say you have a 70 lb draw weight bow. Limb bolts are maxed out.
You put your single cam bow on the draw board, to check on the peak draw weight.

OOOOPS. ONLY get 68 lbs max draw weight.
You want 71 lbs mAX draw weight.

SIMPLE.
THROW away the tape measure.
REALLY.
SERIOUSLY. HIDE it. Put your tape measure away.

Don't need it.
FORGET specs.

The ONLY THING you should care about is that the MAX draw weight makes you happy.
YOu measured the MAX draw weight (limb bolts at maximum) and you ONLY got 68 lbs,
and you want 70 lbs MINIMUM and 71 or 72 lbs MAX draw weight would make you SUPER DUPER HAPPY.

So,
we work the buss cable SHORTER and SHORTER and SHORTER
to get the draw weight correct.

*NO,
if you shorten the bowstring, your DRAW WEIGHT GOES DOWN,
but I'll get to that LATER.*

So,
you put your fingers on the BUSS CABLE
and you ride the BUSS CABLE all the way down to the BOTTOM end loop,
of the long center leg.

YOU add say 2 twists to the LONG center leg, the BOTTOM end loop.

So,
back to the draw board
and you measure the draw weight
and the draw weight is ONLY 69.5 lbs.

DARN.

Back to the bowpress
and you add some twists to SHORTEN the YOKE legs,
cuz you want to keep the buss cable looking pRETTY,
so you add 1.0 twist to SHORTEN the LEFT yoke leg
and
so you also add 1.0 twists to SHORTEN the RIGHT yoke leg.

Now,
back to the draw board and scale
and you now get 70.5 POUNDS max draw weight.

BACK to the bow press
and you add ONE more twist to the LONG center leg of the buss cable, the BOTTOM end loop.

BACK to the draw board and scale
and you measure the MAX draw weight,
and FINALLY you get 71 POUNDS MAX draw weight.

IF this MAX draw weight makes you happy,
then,
we are DONE with the buss cable.

NO TAPE measures were injured during the making of this MOVIE.

*THe ATA does NOT matter,
as long as you are HAPPY WITH THE MAX DRAW WEIGHT.

PERIOD. *


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## nuts&bolts (Mar 25, 2005)

djorgensen3 said:


> He is saying "Both" because it takes the correct length string AND cable to get to the correct ATA. It isn't really one or the other. You CAN use one or the other to fine tune your particular draw length and cam rotation (within reason) however. Adjusting (twisting or untwisting) one or the other will have an affect on the ATA shorter or longer. The specs for a bow are guidelines that you should try to follow closely and if you have to stray too far from them, you probably need different string, cable and/or cam to get back closer to the bow specs.


SERIOUSLY,
forget ATA.

FOCUS more on the max draw weight,
with the BUSS CABLE,
to get the MAX draw weight that makes you happy.


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## nuts&bolts (Mar 25, 2005)

Once you have the MAX draw weight that makes you HAPPY,
say 71 lbs for a 70 lb draw weight single cam bow...

then,
we now work the bowstring.

The BOWSTRING is NOT tuned to hit a certain mark on the tape measure,
to just MATCH ATA.

The BOWSTRING is twisted SHORTER,
to change the cam rotation position,
cuz on a SINGLE CAM,
the cam starting rotation position,
has a LARGE effect on the TALLNESS or FLATNESS of your arrow groups.

If you are shooting 10-inch TALL arrow groups,
and you want to cut that down to 5-inch TALL arrow groups...

then,
we tweak the bowstring LONGER or SHORTER
to influence the starting rotation position of the cam.

So,
if you shoot bareshafts,
then, the goal is to TUNE your BOWSTRING, on your single cam bow...

either SHORTEN the bowstring, and the cam changes the STARTING rotation position in ONE direction

or

LENGTHEN the bowstring, and the cam changes the STARTING rotation position in the OTHER direction.

So,
when you find the SWEET SPOT for the single cam starting rotation position,
your fletched arrow groups get a LOT TIGHTER...MORE FLAT.

Technical term is called "LEVEL NOCK TRAVEL".

So, the single cam bowstring is SUPER DUPER LONG.

Any bowstring has two ends.

The SINGLE cam bowstring has the end loop, the DOWNHILL end loop, which is CLOSEST to the peep sight.
I call this the SHORT end loop for a single cam bowstring.

The SINGLE cam bowstring has the other end loop, the UPHILL end loop, which is FARTHEST away from the peep sight,
so with your fingers,
slide along the bowstring ABOVE the peep sight, go up to the idler wheel
and then back down the bowstring, all the way down to the cam. THIS is the LONG end loop, for a single cam bowstring.

So,
let's say you want to try SHORTENING the bowstring,
to see if this will make your GROUPS TIGHTER, FLATTER.

Gotta add twists to BOTH ends of the bowstring,
the SHORT END and the LONG END (both end loops)
to keep the peep sight pointed STRAIGHT AHEAD.

IF you add 2 twists to the DOWNHILL end loop, the SHORT end loop, the end loop closest to the peep sight..

then,
try 4 twists or 5 twists for the OTHER end loop, the LONG end loop,
the end loop FARTHEST AWAY from the peep sight
to keep the peep sight pointed DEAD STRAIGHT AHEAD.

FORGET ATA,
and focus more on your SHOOTING RESULTS.

IF adding a little bit of twists to BOTH ends of the bowstring,
say 2 twists on the CLOSER end LOOP, and 4.5 twists on the FARTHER AWAY end LOOP...

if this makes your arrow groups TIGHTER...

then,
throw away the tape measure,
and keep going.

Do the extra twists again,
to both ends of the bowstring,
and FIND your sweet spot for adding extra twists to the bowstring,
until you get the ABSOLUTE tightest fletched arrow groups.

Cuz,
TIGHTER arrow groups are MUCH more important than using a TAPE measure to decide how many twists to add to the bowstring.

Now,
if you DO add twists to SHORTEN a bow string,
to find your SWEET SPOT..

there ARE side-effects.

As you add MORE and MORE twists to the bowstring,
the draw weight is GOING TO DROP..the draw weight will GO OUT OF SPEC, and get LOWER and LOWER and LOWER, as you SHORTEN a bowstring.

As you add MORE and MORE twists to the bowstring,
the HOLDING weight is GOING TO INCREASE..the HOLD weight will GO OUT OF SPEC, and get HIGHER and HIGHER and HIGHER, as you SHORTEN a bowstring.

YOu may like the FEEL of the shorter bowstring,
you may find the HIGHER holding weight WEIRD feeling.

FOCUS more on your fletched arrow results,
the SIZE of your arrow groups.

See if making the bowstring SHORTER
improves your RESULTS.


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## Gary73 (Jan 11, 2008)

I would agree with what has been said, but I do use a tape measure at first to hit specs, I then check poundage. I aim for 60.75lbs draw on my Marquis with the limbs maxed out. After 6-7 years with this bow and 5-6 sets of string changes I just know what works on it.

I find if my limbs are maxed out and my axle to axle is correct both sides as long as the timing is correct on the cam it will be within 1-2 twist of where I want to be for poundage.

As a basic guide to idler lean for me I simply install new strings cables hit specs check poundage at max, ensure cam timing is correct. I then move my string stop out of the way and take the strings/cables out of the rollers. I then use a 2 arrows as straight edges and place each one against each side of the idler pointing down towards my peep. I set my yoke if I have to so that the peep and string sit evenly between the 2 arrows. When I put the strings/cables back into the roller and put my string stop back the idler is leaning but when at full draw runs straight. I will normally shoot a bullet hole through paper straight away, if not only a tiny adjustment to the yoke is required.

I guess it's whatever works for you, but on my marquis if it's in spec and timed it's close to being right poundage wise.

Nuts&bolts is the expert, and I would go with what he says. I just need a quick and easy setup that gets me shooting and my bow, field points and broads heads working together.


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## SonnyThomas (Sep 10, 2006)

Always long in detail, but follow nuts&bolts instructions. Like he said, ata is just a number. Listed max draw weight is what you shoot for. Use to be factory tolerance for ata was +/- 3/16". Example; 33 3/16" is spec, but 33 3/8" give listed max draw weight you're good to go. If 33" gives listed max draw weight you're good to go.
Cam orientation. You'll probably go back and forth a bit, but once oriented you should have 0" to no more than 1/4" high nock setting. Most always I get 1/16" high nock setting. And it's not to say that high is bad, it just might prove better. BUT never lower than 0"


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## Don_Swazy (Jul 9, 2013)

Nuts&Bolts, Gary73, and SonnyThomas,
Thank you guys very much for the help. 
I very much appreciate it... Sincerely.

Don


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## Stealth (Jun 29, 2014)

I'm working on thus with my PSE stinger 3G
It's supposed to be 70 # draw but measures only #60 maxxxed now. Ata spec is 33, measures 33 3/8
Ignoring ata, I would like to have peak weight around 65 at least. If I understood correctly, if I am ok with less than specced max draw, will that give me lower holding weight % than if I tune it up to 70#, ie higher % let off? Or is it best to get it to 70 maxxed and back off the limb bolts to 65 for best performance?


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## nuts&bolts (Mar 25, 2005)

Stealth said:


> I'm working on thus with my PSE stinger 3G
> It's supposed to be 70 # draw but measures only #60 maxxxed now. Ata spec is 33, measures 33 3/8
> Ignoring ata, I would like to have peak weight around 65 at least. If I understood correctly, if I am ok with less than specced max draw, will that give me lower holding weight % than if I tune it up to 70#, ie higher % let off? Or is it best to get it to 70 maxxed and back off the limb bolts to 65 for best performance?


So,
we are getting into "FRANKEN-stein bow" territory.

When you understand what the bowstring does, for a single cam bow
when you understand what the buss cable does, for a single cam bow...

you can RE-DESIGN the string length, and the buss cable length
to get what YOU want.

So,
the BUSS CABLE length
controls MAX draw weight with the limb bolts at maximum.

MAKE the buss cable 10 FEET longer, than SPEC
then, with limb bolts maxed out,
you will have a 2 lb draw weight weight bow.

MAKE the buss cable 4 FEET shorter, than SPEC
then, with limb bolts maxed out,
you will have a 1,000,000 lb draw weight bow.

YOU GET the IDEA.

Sooo,
with your CURRENT BUSS CABLE length,
you have a ATA = 33-3/8ths.

SPEC is supposed to be 33-inches.


So,
when you SHORTEN the buss CABLE..

PRESS your bow

ADD say 3 twists to the LONG center leg
to make the LONG center leg SHORTER

and then,
goto the TOP yoke leg end loop, LEFT SIDE
and add maybe 2 twists to SHORTEN the LEFT LEG

and then, 
goto the TOP yoke leg end loop, RIGHT SIDE
and add maybe 2 twists to SHORTEN the RIGHT LEG.

THIS is not rocket science.

You have shortened the YOKE cable, also called BUSS cable.

NOW,
goto your draw board
and measure your NEW draw weight.

DID you get 65 lbs?

You only got 63 lbs, you say?????

Well,
you know what to do.

Go back to the bow press
and SHORTEN the LONG center leg of the buss cable
and
ADD some more twists to the YOKE LEG, LEFT SIDE
and
ADD some more twists to the YOKE LEG, RIGHT SIDE.

CHECK draw weight again.

BACK and forth.

GOTO the bow press.
ADD twists to the buss cable, EACH end loop.

BACK to the draw board, and scale
and measure the NEW draw weight.

REPEAT as many times as you need,
until you hit 65 lbs of draw weight,
with the limb bolts at maximum,
and keep checking the NEW draw weight,
EACH time you shorten the buss cable
EACH time you add some twists to EACH end loop (ALL THREE) of the buss cable.

STOP when you hit 65 lbs of draw weight.

EASY
PEASY


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## nuts&bolts (Mar 25, 2005)

Stealth said:


> I'm working on thus with my PSE stinger 3G
> It's supposed to be 70 # draw but measures only #60 maxxxed now. Ata spec is 33, measures 33 3/8
> Ignoring ata, I would like to have peak weight around 65 at least. If I understood correctly, if I am ok with less than specced max draw, will that give me lower holding weight % than if I tune it up to 70#, ie higher % let off? Or is it best to get it to 70 maxxed and back off the limb bolts to 65 for best performance?



So,
on a SINGLE CAM...

you cannot adjust the letoff,

cuz if you DO...

then,
you lose LEVEL nock travel...

You will get a HIGH paper tear
or
you will get a LOW paper tear....
cuz on a SINGLE cam bow,
there is only ONE sweet spot...for EACH length of the buss cable.

MEANING,
when you CHANGE the length of the buss cable for 65 lbs MAX draw weight...

there is ONLY ONE length for the single cam bow string,
that will give you BEST results...



20 yards
level strip of masking tape

FLETCHED arrow SMACKS the top edge of the masking tape
and
BARESHAFT arrow smacks the SAME TOP EDGE of the MASKING tape.

I find this MUCh more accurate than a "bullet hole" through a paper tuner, several feet away.

SAME concept.


So,
once you SET the buss cable length,
to DELIVER 65 lbs of draw weight...

then, since you SHORTENED the buss cable, to deliver 65 lbs of MAX DRAW WEIGHT
you must also SHORTEN the bowstring....

and you keep tWEAKING The length of the bowstring (add twists at BOTH ENDS)

until you get FLETCHED arrows and BARESHAFT arrows hitting at the SAME Exact height,
20 yards away....

or
if you prefer paper tuning...

until you get your "BULLET HOLE".

YOu can FUDGE your results a little bit,
by going HIGHER or LOWER on the d-loop/nocking point.

WHEN you make your single cam bowstring LONGER,
your STARTING rotation position for the cam CHANGES ONE direction.

WHEN you make your single cam bowstring SHJORTER,
your STARTING rotation position for the cam CHANGES the OTHER direction.



ON my MATHEWS Apex 7....

THIS cam starting rotation position works BEST.



The Apex 7 cam has two dimples (I added GREEN PAINT).

So,
if I make the bowstring LONGER and LONGER and LONGER...then, the cam rotates to a NEW starting position, and the accuracy SUFFERS (arrow groups get TALLER).

So,
if I make the bowstring SHORTER and SHORTER and SHORTER...then, the cam rotates to a NEW starting rotation position, and the accuracy SUFFERS (arrow groups get TALLER).

THERE is a MATCHED pAIR,
for NEW buss cable length,
and NEW bowstring LENGTH.

Once you SET the buss cable length to deliver 65 LBS of draw weight, with limb bolts at MAXIMUM...

there is only ONE sweet spot for bowstring LENGTH,
that gives you the BEST result...(LEVEL nock travel....fletched and bareshafts hit at the SAME exact height).


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## Stealth (Jun 29, 2014)

Excellent, now I get it.
Thanks, off to build a bow press!


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## Stealth (Jun 29, 2014)

Checking out my bow again an noticed there are factory timing marks on the cam, currently a little off alignment. These are prob just for reference, though, not necessarily correct for my setup , correct?
Also, once I have the cable set for draw weight, then string set for nock level, if I back off the limb bolts for lower draw weight that should not affect nock level since cable and string are still balanced, correct?


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## BAMA32577 (Sep 24, 2012)

how would this affect draw length as ata gets longer and bh gets shorter


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## frd567 (Jan 30, 2012)

BAMA32577 said:


> how would this affect draw length as ata gets longer and bh gets shorter










This should help.


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## Evolution905 (Aug 10, 2014)

Stealth said:


> Excellent, now I get it.
> Thanks, off to build a bow press!



You can do all these adjustments including cable and string replacement without a bow press on the single cam bow. https://www.youtube.com/watch?v=ta-PW-Fq12U


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## Gary73 (Jan 11, 2008)

nuts&bolts said:


> Once you have the MAX draw weight that makes you HAPPY,
> say 71 lbs for a 70 lb draw weight single cam bow...
> 
> then,
> ...


Changing strings and trying your method now, going to forget ata and hit 61lbs using power cable then using main string to adjust cam rotation.


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