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Discussion Starter · #1 ·
Hey brothers - got a new set of arrows that I’m attempting to tune my bow for. Bow is a Mathews V3, 70 pound / 85% mods, draw length at 30.5. Victory RIP TKO in 250 spine, 29” of carbon, 25 grain insert, 150 grain point / head, standard nock and no fletchings yet. Shooting with no adjustment to my bow, I was getting a 5/8 - 3/4 nock low tear with an ever so slight nock right tear. Tuning chart said move nocking point up and/or lower rest. Not much room to move the rest lower, so I started working on nock point. First picture is where I ended up and I’m now shooting pretty close to bullet holes at 6 feet (maybe slightly nock high now?) but at 20 yards my bare shaft is 6 inches low. Clearly I need to do more than play with nocking point. I have read about cam sync, and looking at the reference holes in my cams, they don’t match up. Top cam the cable is toward the string in the hole, while the bottom cam is right in the middle. So I think I may need to add a twist to the cable that attaches to the top cam to advance it? And then set nock point and rest back to level and start again. What say yall?
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Man d loop shouldn't have to be that high...I'd wager there is major cam synchrony issues.

Do you have a draw board? The cam timing holes are reference but can be off with the cams in sync but I'd imagine this time they're-telling you the cams are NOT in sync.

Was the bow in tune before you switched arrows?
 

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Discussion Starter · #3 ·
Man d loop shouldn't have to be that high...I'd wager there is major cam synchrony issues.

Do you have a draw board? The cam timing holes are reference but can be off with the cams in sync but I'd imagine this time they're-telling you the cams are NOT in sync.

Was the bow in tune before you switched arrows?
I need to build a draw board. I assume the bow was in tune, but that would mean trusting the shop that set it up - they never had me shoot it after installing new string and cables back in Jan / Feb. It was shooting fletched Axis 300s well - broadheads were hitting at 20, but as soon as I started shooting bare shafts I noticed some issues. I’m thinking cam sync too.
 

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Add a twist to the cable end that attaches to the top cam. That will slow the top cam and might allow you to get the nock back to a reasonable position. You should not need the nock that high! It might take more than one full twist, but start with one. What have you got to lose by trying!?

NC

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Discussion Starter · #7 ·
Add a twist to the cable end that attaches to the top cam. That will slow the top cam and might allow you to get the nock back to a reasonable position. You should not need the nock that high! It might take more than one full twist, but start with one. What have you got to lose by trying!?

NC

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Exactly my thinking!
 

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Got it. Found it interesting that the top is wearing faster than the bottom - thinking that means the top might be hitting first?
that's possible but against what I would think - someone should check me on this but I think if there's a nock low tear, then you'd speed up your top cam bc it's slightly behind the bottom cam.

I would think whichever cam is hitting first would have more wear, but then again, maybe what youre seeing is just a product of uneven wear on the serving that has nothing to do with your current presumed timing problem.

if you don't have someone that can watch you, maybe try to get a video with your phone. If that doesn't work, could problem solve by putting in a full twist into the top cable and see if the tear gets better (AFTER you've set your rest and nock point back to level/through the Berger hole)!
 

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Discussion Starter · #12 ·
that's possible but against what I would think - someone should check me on this but I think if there's a nock low tear, then you'd speed up your top cam bc it's slightly behind the bottom cam.

I would think whichever cam is hitting first would have more wear, but then again, maybe what youre seeing is just a product of uneven wear on the serving that has nothing to do with your current presumed timing problem.

if you don't have someone that can watch you, maybe try to get a video with your phone. If that doesn't work, could problem solve by putting in a full twist into the top cable and see if the tear gets better (AFTER you've set your rest and nock point back to level/through the Berger hole)!
Yep, I think you’re right according to the Gold Tip tuning chart. Speed up top / slow down bottom. Most likely the uneven wear is unrelated in this case. Appreciate the insights!
 

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I'd go off of the bareshaft at 20 yards, not the paper tune. Bareshaft hitting low at 20 means you need to raise the rest or lower nocking point. Arrow should be close to level at brace, not angled down as much as you show in the first picture.

Check timing, then set nock height and rest so that the arrow is level with the bottom of the shaft halfway up the berger hole.
 
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Discussion Starter · #15 ·
Add a twist to the cable end that attaches to the top cam. That will slow the top cam and might allow you to get the nock back to a reasonable position. You should not need the nock that high! It might take more than one full twist, but start with one. What have you got to lose by trying!?

NC

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One full twist to the top cam cable end took my low tear from 3/4 to 1/4. So obviously I need to add one half twist and I should be pretty close! I also measured my ATA after the full twist and found that I'm just slightly longer than spec at 31 1/8(ish). Would that additional half twist bring my ATA back into spec also?
 

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Discussion Starter · #16 ·
One full twist to the top cam cable end took my low tear from 3/4 to 1/4. So obviously I need to add one half twist and I should be pretty close! I also measured my ATA after the full twist and found that I'm just slightly longer than spec at 31 1/8(ish). Would that additional half twist bring my ATA back into spec also?
Failed to note - this is also with the nock point set at the exact center of the string (as measured between the cams) and rest set at 90 degrees.
 

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Failed to note - this is also with the nock point set at the exact center of the string (as measured between the cams) and rest set at 90 degrees.
Exact center of the string isn't always the best location depending on cam/riser design. Arrow level through the berger hole (bottom edge of arrow somewhere in top half of the hole) is typically the best starting point.

1/8" of ATA off isn't a big deal at all and that spec is only for the limbs being bottomed out (will be different if you back off limbs for lower poundage).
 
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Discussion Starter · #18 ·
Exact center of the string isn't always the best location depending on cam/riser design. Arrow level through the berger hole (bottom edge of arrow somewhere in top half of the hole) is typically the best starting point.

1/8" of ATA off isn't a big deal at all and that spec is only for the limbs being bottomed out (will be different if you back off limbs for lower poundage).
Gotcha. Arrow is level through Berger at this point. Limbs are bottomed out.
 

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Were you able to check if the stops are hitting at the same time?

Sounds like you are close. As I said earlier, the bareshaft at 20 yards (or a broadhead) compared to fletched will tell you more than a paper tune.

Your original post didn't make sense to me because you said you had a nock low tear in paper, but your bareshaft was hitting 6" low. A nock low tear would make your bareshaft hit high.
 
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Discussion Starter · #20 ·
I'm going to throw together a draw board tonight and will check the stops. Sorry for the confusion - bare shaft hitting low was after moving the nock point up to that crazy height (picture). That eliminated the tear, but now the bare shaft was hitting low. Having the nock point that high to get rid of the tear led to needing to add twists to the cable. So I reset the nocking point, added the twists, and started shooting through paper again. I have decided to get as close to a bullet hole as I can through paper before fletching and then will leave a bare shaft for final tuning at 20 yards. Does that seem like a good plan?
 
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