# Hoyt Carbon Matrix with RKT Cam, Tuning Question



## Guardian Shoote (Jan 11, 2007)

What year matrix? is this a matrix that came with fuel or xtr? i would pm Ray knight he can help. Good luck


----------



## srcarlso (Mar 3, 2005)

It is a 2012 Hoyt Matrix with the RKT cam.


----------



## Ray knight (Jan 9, 2012)

Can you measure your strings and cables? Is it a long draw model? Also if you can post a pic of the cable side of the bottom cam at rest. Are your limbs backed out? Or down all the way?


----------



## Ray knight (Jan 9, 2012)

Longer cables will power draw weight and lower draw length. Shorter string will take weight off and increase holding weight/decrease valley as well as shorten draw length. My best guess is your strings are not sized properly. They may be for the long draw model. And those string measurements from Hoyt's tune charts are off. I have spoken to them a few times about them as well. If you use those lengths the DL is way too long. I had to go 1" short on the string to get it right.


----------



## srcarlso (Mar 3, 2005)

Here is the picture of the bottom cam, cable side. To answer your question above, the limbs are buried so I was expecting 70# given the other measurements. I am not sure if the starting cam position is right however...cables are just about without twist now. It is not a long draw model, I did measure the string and control cable and they were close to what the tune charts call for. However, if I used the factory string dimension, I was 1" long in DL>

View attachment 1599210


----------



## dwagoner (Sep 27, 2007)

how did this problem arise?? did you swap strings and trying to get into tune? or did you buy this bow this way?? SO buss seems twisted fine, control cable is straght and string is super twisted up right??


----------



## srcarlso (Mar 3, 2005)

I bought the bow new last summer...was for my son. He wanted new strings due to some fraying on the factory string around the peep so we put A-B on last fall. He has grown so much that the extra 1/2+ of DL at 30" actually worked for him. With 30" modules and a DL (measured) of 30.5"+, ATA was OK and so was the draw weight. String twist was normal.

He is now shooting a PSE for indoor so I am shooting his bow. My DL is around 29.5" I started twisting the string with the B modules installed to get to 29.5". That is where I noticed the ATA starting to shorten with all the string twist so I untwisted the cables to maintain ATA at spec the best I could. Both cables are nearly without twist. The string is tightly twisted. With ATA very close, BH good, and cam timing good, my DW is only 65#.


----------



## Ray knight (Jan 9, 2012)

srcarlso said:


> Here is the picture of the bottom cam, cable side. To answer your question above, the limbs are buried so I was expecting 70# given the other measurements. I am not sure if the starting cam position is right however...cables are just about without twist now. It is not a long draw model, I did measure the string and control cable and they were close to what the tune charts call for. However, if I used the factory string dimension, I was 1" long in DL>
> 
> View attachment 1599210


I can tell by that pic that either the string is short or the cables are long. At factory settings, the peg that mounts the lower control cable is almost fully wrapped around. Its pretty far away in that picture. I have a feeling the string and cable lengths are both off.


----------



## Ray knight (Jan 9, 2012)

srcarlso said:


> I bought the bow new last summer...was for my son. He wanted new strings due to some fraying on the factory string around the peep so we put A-B on last fall. He has grown so much that the extra 1/2+ of DL at 30" actually worked for him. With 30" modules and a DL (measured) of 30.5"+, ATA was OK and so was the draw weight. String twist was normal.
> 
> He is now shooting a PSE for indoor so I am shooting his bow. My DL is around 29.5" I started twisting the string with the B modules installed to get to 29.5". That is where I noticed the ATA starting to shorten with all the string twist so I untwisted the cables to maintain ATA at spec the best I could. Both cables are nearly without twist. The string is tightly twisted. With ATA very close, BH good, and cam timing good, my DW is only 65#.


Thats exactly what happens with longer cables and shorter string. Shorter DL, lower draw weight, higher holding weight, less valley. With that many twists out of the cables, you are going to ruin them. Eventually they will begin to untwist under the servings and you will have issues with that.


----------



## srcarlso (Mar 3, 2005)

Ray knight said:


> Thats exactly what happens with longer cables and shorter string. Shorter DL, lower draw weight, higher holding weight, less valley. With that many twists out of the cables, you are going to ruin them. Eventually they will begin to untwist under the servings and you will have issues with that.


Agreed...getting new cables and strings (again). I am not shooting it like this...was trying to get the bow into spec which I cannot.


----------



## srcarlso (Mar 3, 2005)

Ray knight said:


> I can tell by that pic that either the string is short or the cables are long. At factory settings, the peg that mounts the lower control cable is almost fully wrapped around. Its pretty far away in that picture. I have a feeling the string and cable lengths are both off.


Thanks for the input....it is appreciated. I have no room to untwist the cables to get the peg around and if I try to twist up the lower cable in the pic my ATA is way off.


----------



## Ray knight (Jan 9, 2012)

srcarlso said:


> Thanks for the input....it is appreciated. I have no room to untwist the cables to get the peg around and if I try to twist up the lower cable in the pic my ATA is way off.


I suggest measure your strings! I still think they are going to be off quite a bit.


----------



## srcarlso (Mar 3, 2005)

Ray knight said:


> I suggest measure your strings! I still think they are going to be off quite a bit.


Since the buss cable was straight, I ordered new strings and put them on today. With very little work on tuning, all the measurements came in right on spec including ATA, DW, BH, DL. Cam timing is good and starting position is right where it should be. Twists on string and both cables look good...no where near straight.

Thanks for the comments guys!


----------



## NoFences4Me (Jan 22, 2009)

Marked for later.


----------



## huteson2us2 (Jun 22, 2005)

I have a carbon element and the first time I built new strings and cables for it, I went by the Hoyt chart. They were wrong. Took the string and cables off my bow and measured them and they were different from the chart. Built new threads using these measurements and everything was perfect. So I called Hoyt and informed them and they told me to buy their string and cable as mine were not right and that their chart is correct. 

I learned a lesson from this. Always measure the length of the string and cables on your bow that is set up right instead of going by a chart that may or may not be right.


----------

