Hoyt Tuning ?'s

[deathtoll]

A hybrid cam system is a 3 piece rigging system.

a) bowstring

b) buss cable (cable with 3 end loops)

c) control cable (cable with only 2 end loops).


When you understand how these 3 pieces work together,
you will no longer need to worry about timing dots, timing slashes/marks/lines, etc.


So,
a little history.


FIRST, came the single cam system,
with 2 pieces to the rigging system.

a) SUPER DUPER long bowstring

b) buss cable.


SECOND, came the hybrid cam system.


The SUPER DUPER long bowstring got cut into two pieces.

FRONT half of the SUPER DUPER long bowstring, is now the shorter bowstring on the hybrid cam system.
BACK half of the SUPER DUPER long bowstring, is now the "control cable" on the hybrid cam system.


So,
why is this important?


Cuz,
ultimately,
what we want is LEVEL nock travel.

If we have LEVEL nock travel,
then we have the cam rotation position in the correct spot.

GOOD arrow flight.
TIGHT fletched arrow groups.

That is what the cam designer is aiming for.


So,
if the timing dots are faded..
so, if the cam system USED to have timing slashes / lines....and no longer has these reference marks...
no biggie.


So,
I just finished tuning up a hybrid cam bow for flopduster.

Bowstring.
Control Cable.
Buss cable.


WHAT HAPPENS WHEN YOU UNTWIST THE CONTROL CABLE?

As you lengthen the control cable longer and longer, by removing twists,
the TOP CAM draw stop will move CLOSER to the cable, when at full draw.

If you pull your hybrid cam bow to full draw,
and you see a GAP between the TOP CAM draw stop and the cable,
when you LENGTHEN / UNTWIST the control cable,
the GAP GETS SMALLER.


WHAT HAPPENS WHEN YOU ADD TWISTS TO THE CONTROL CABLE?

As you shorten the control cable, by ADDING twists,
the TOP CAM draw stop will move AWAY from the cable, when at full draw.

If you pull your hybrid cam bow to full draw,
and you see a GAP between the TOP CAM draw stop and the cable,
when you SHORTEN / ADD TWISTS to the control cable,
the GAP GETS LARGER.



So,
now the buss cable.

We all know that the buss cable is what controls the MAX draw weight.

If we have the limb bolts maxed out,
and the limb sticker says the bow is a 60 lb bow,
and
we are only getting 58 lbs of draw weight...

we know that we add a few twists to SHORTEN the buss cable
and
we will soon be getting factory spec on the draw weight,
and the bow will deliver 60 lbs of draw weight,
when the buss cable has enough extra twists,
if the bow was a little low on draw weight.

TWEAK twists in the buss cable to hit factory spec for draw weight.

If the MAX draw weight is a skosh low, ADD twists to the buss cable.
If the AMX draw weight is a skosh high, REMOVE twists in the buss cable.


NOW, WHAT ABOUT CAM SYNC AND THE BUSS CABLE?


You also tweak the buss cable to adjust cam sync (top cam rotation position at full draw).

As you shorten the BUSS cable, by ADDING twists,
the TOP CAM draw stop will move TOWARDS the cable, when at full draw.

If you pull your hybrid cam bow to full draw,
and you see a GAP between the TOP CAM draw stop and the cable,
when you SHORTEN / ADD TWISTS to the BUSS cable,
the GAP GETS SMALLER.

So,
at least for the Hoyt Cam.5 system:


a) tweak the buss cable to get max draw weight at factory spec.
....ATA should be close to factory spec.

b) tweak the control cable twists, so that the top cam draw stop and the bottom cam draw stop hit the cables at the SAME TIME
....this is a good, and easy to find starting point.

c) if you have a draw board, check for draw length
...draw length might be to spec
...draw length might be a little long
...if the bow is working for you (you can hold steady) then, leave the string twists alone

d) now go and creep tune your bow at 20 yards
....you will be tweaking the buss or control cable (your choice) to adjust the cam rotation position to find the sweet spot
....the sweet spot for cam rotation, will give you the smallest vertical spread in your arrow groups, when aiming at the top edge of a long piece of horizontal duct tape
....if NORMAL pressure into the wall of your bow has your arrows missing the top of the duct tape by 2 inches HIGH
....IF HARDER than normal pulling pressure into the wall of your bow has your arrows missing the top of the duct tape by 6 inches HIGH
....THEN, you have a 4-INCH vertical spread, when creep tuning your bow.

....sooooo, pick a cable, and tweak the twists....I like to use the control cable and try REMOVING a full twist
....if the NORMAL pulling into the wall arrows, and if the HARDER into the wall arrows are now only 1-INCH apart vertically.....we are going in the CORRECT direction for twists.

....keep tweaking the twists until you get ALL your arrows the SAME height above the top edge of the duct tape.


This way,
you don't need the reference marks or timing dots.

Just CREEP tune your hybrid cam bow,
to find the sweet spot for your cam rotation position (cam sync).

 

[deathtoll]

Borrowed that tuning tech from another site. Works wonders.

 

[deathtoll]

I have a spyder turbo & my gf has a carbon element.
Also the slight left cam lean is right on. Some of them like to be tuned where the lean lines the arrow up at rest with the d loop part of the string. Others play nicer if the centre crossover is just above the sting stop.

 

[deathtoll]

Also I have found that both bows seem to tune & pound up best when I start by tensioning up the yoke/buss cable to where the control cable on the bottom cam almost loops back around onto itself. About a credit card thickness from the end loop touching the cable.
Also they seem to play even nicer if when the top draw stop touches the cable there is a about a credit card gap between the bottom stop & bottom cable. When you draw to shoot, draw until the bottom stop gives you a solid wall.
To improve the wall & make it more solid, replace the bottom draw stop with a bomar draw stop

 

[deathtoll]

Also here is another article worth a read. The difference between timing & synchronising.

First thing first....Cam timing has absolutely nothing to do with the draw stops hitting together at the same time...nothing! Cam timing is also just as critical to single cam bows as it is to dual cam bows. What timing refers to is when things happen during the draw cycle. For example, once you start pulling the string, when the bow hits peek weight, when the bow starts into the valley, and when you hit the base of the valley or stops. Timing is controlled by cam orientation while the bow is at brace. For example, if the cam timing is advanced it will hit peak weight later in the draw cycle and hit the stops, or base of the valley, sooner. Conversely, if the cams are r e t a r d e d peek weight will come sooner and the valley will come later. There really are a lot of important things to consider when setting cam timing. While it is being adjusted you are also adjusting peak weight, draw length, duration or length of the plateau, lettoff, and how much energy a cam stores during the draw cycle. When manufactures have referances on their cams they are giving you a recomended timing position on the cam. This referance is usually the best position for a 29" draw. Another thing to consider while setting the timing on a bow is that two identical bows can have two drastically different draw force curves....all related to timing. Again, it is a fundamental and critical aspect of tuning that has absolutely nothing to do with draw stops hitting together or 2 cams working together...nothing

Synchronization on the other hand is hardly ever mislabeled...but hardly ever used. Synchronization IS getting the draw stops on a dual cam hitting together at the same time or otherwise getting two cam systems working both cams together. It is a critical aspect of tuning any two cam system. I think this is something we all understand so I won't go into detail.

One last effort to convince everyone labeling things correctly is important. I had a customer call a few weeks ago and describe to me how his shop tuned his bow. He called a week before his shop visit and asked me about the timing dots on his Destroyer and how the cables both lied on the outside of the referance dots (which is not necessarily bad in some of the short draw settings). I told him his timing was off and the shop needed to put 5 or 6 twists in the cables (his ATA was long as well) to bring the cables back between the dots. He took the bow to a shop and told them the timing needed adjusted. They proceeded to put the bow on a draw board and checked to make sure the draw stops hit at the same time at full draw. They gave him the bow back and said the timing was perfect LOL. He then handed the bow back and told them that the cables were outside the referance marks on the cam and that the timing needed adjusting. Their response, "We already timed it and that's the only way you can time a bow". Some people should not be working on bows! I've seen this many, many times. Timing is the one thing that is really misunderstood and miscommunicated. More people (especially dealers) should understand this more clearly and that understanding will come harder if we keep meshing these two ideas under one name.