# Hoyt Z3 Cam Tuning



## Dugga Boy (Apr 21, 2003)

Today I finally found the time for tuning my Katera XL.

It's equipped with Z3 Cams 7.0 (draw length by AMO 31.775"), 80# version.

I always prefered the 65%LO over the 75%LO, so I put the draw stop peg into the designated thread hole. Well reading the Hoyt manual, a somewhat "unlogical" advice jumped into my eyes.

So, I started this thread to gather information how YOU tune your Z3 Cam and what experiences you made so far.

I'm sure that has been discussed before but I only have found some info about the Cam&1/2, not the Z3 which is different.

I made some photos while the bow was in my drawboard. Also I measured the stored energy of the different settings. No changes on the limb bolts were made, only twisting the cables.

Here is how the bow comes out of the box. It got 75%LO.
Cams are synchronized in roll over (I used some of the holes for reference) and both cables touch the draw stop at the same time.
On the pics below you always see the top cam on the left and bottom cam on the right.











As already mentioned, I want the bow in 65%LO, so I moved the peg.
Naturally the control cable can't reach the stop now while the bus cable already touches the peg.











So, Hoyt recommends to twist the cables until both touch their stops at the same time, looking like this:











I needed to take two twists off the control cable to reach that position (or add 2 twists into the buss cable).
Now the cables touch the stop in time BUT the cams are not longer synchronized in roll over. That mostly generates unwanted nock travel which makes that advice to be found in the manual unlogical to me.

*From a technical point of view there must be a thread hole close to the stop of the top cam, allowing to screw-in another peg. Only that way sychronization and timing would be as they are supposed to be.*

Here some of my datas:
Just moving the peg into 65% thread hole (photo 2):
Draw weight max. 84.8#
63.75% LO
126.2ftlb. stored energy

Twisting the cables after moving the peg into the 65% thread hole (photo 3)
Draw weight max. 83.6#
67,9% LO
124.6 ftlb. stored energy


*Please let me know how do you tune your Z3 Cams.*

Thanks for your input

DB


----------



## GCOD (Nov 24, 2006)

http://www.archerytalk.com/vb/showthread.php?t=207391


----------



## Dugga Boy (Apr 21, 2003)

Thanks.

I know this thread but I haven't found an answer in there.

Today I built a device into my drawboard which can draw and measure the nock travel, so I will figure the solution by myself.

DB


----------



## Honeymonster (Nov 3, 2005)

ttt

Looking forward to buy a bow with Z3 cams @65%. So I`m interested how this turns out as well.


----------



## Dugga Boy (Apr 21, 2003)

Okay, I measured the nocktravel on my drawboard.

Having both cams sychronized in timing and rollover, it's 0.51" positive travel (positive means that the nocking point goes towards the top cam).

Setting the peg to 65%LO and twist-in the buss cable, ensuring both cables hit the stop (pic 3, thread #1), nocktravel decreases a bit down to 0.47".

That decrease is normal, since a shorter buss cable allows a somewhat longer rollover of the top cam, counteracting the "positive" nock travel.

By the way, re-timing the cams (following the Hoyt manual) as to be seen on pic 3 extend the draw length by 1/4".

Nock travel is one thing, cam acceleration another.

Due to the re-timing the top cam accelerates somewhat later which could possibly compensate the nock travel. On the other hand that would mean that the cam is not well engineered for the guys prefering the 75%LO because of the maximum nock travel.

Seems that I will have to do some intense testing with bare shafts and paper tuning to verify how the arrow flight gets effected by different settings.

Will post as soon as I got some news.

DB


----------



## Hozer (Jan 26, 2008)

Not to be an arse, but someone please PM me with a reason why the hybrid system is superior. Seems like a tuning nightmare. The CAT cam system seems to solve many problems, but then again, I don't own one.


----------



## archerm3 (Jan 4, 2007)

Hozer, Hybrids were supposed to alleviate timing problems when a string or cable stretched over time, just like a solocam, but with more control over the nock travel. But, they still go out of time. Just not quite as easily as a traditional 2cam bow.

Dugga boy, I would like to see your setup to measure nock travel on your draw board. Im curious about methods of doing it. tyia.


----------



## Dugga Boy (Apr 21, 2003)

archerm3 said:


> Dugga boy, I would like to see your setup to measure nock travel on your draw board. Im curious about methods of doing it. tyia.


I didn't take a pic yet but it looks similiar to this one:

xxx.elitearchery.com/forums/showthread.php?t=2205

DB


----------



## archerm3 (Jan 4, 2007)

Dugga Boy said:


> I didn't take a pic yet but it looks similiar to this one:
> 
> xxx.elitearchery.com/forums/showthread.php?t=2205
> 
> DB


couldn't see the pic, not a member and don't wanna be.


----------

