# cam timing & nock high tear



## I BOW 2 (May 22, 2002)

I have found on the single cam that if everything is set up properly and shot with good form a weak spine arrow will show nock high and a stiff spined arrow will show nock low. I would play with the spine first and go from there. Ken


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## krazycurt (Jan 2, 2009)

Not sure what type of rest your shooting but sometimes to light of tension will cause the rest to bounce back up hitting your shaft giving you a tail high tear.By what you have said lowering poundage or your tip weight works so try increasing your tension on your rest or if you can try cutting your shafts shorter a little at a time to stiffen them up.Because the lighter tip and poundage actually stiffen the spine of your shafts.The shafts you have should be stiff enough.



UOTE=Dan'l;1054984198]I am pulling my hair out (what's left of it) trying to fix a nock high tear on a Mathews Q2. Setup is 68#. 29.5" GT XT7595. 100 gr. point. 3" bohning Vanes. Release. Golden Premier rest. NO clearance problems. Bow shoots / groups well, but broadhead tuning and papertuning show nock high. Nock point is 1/8" BELOW center. Even tiller. Everything I read says the Mathews should tune out above center. Stiffness on the rest tension is as light as I can get it to reliably return to full up with arrow on rest. If I drop my draw weight to 60# or drop my point weight to 65 gr. I get a bullet hole. On target says this shaft is TOO stiff. Is it possible that it is still under spined on this setup?

My last resort has been messing with the cam timing. Can anyone tell me if an over or under rotated cam would cause nock high. Which? I've made some adjustments in both directions but have not seen an appreciable difference. [/QUOTE]


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## red44 (Apr 11, 2005)

Are you using a loop?


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## Dan'l (Feb 4, 2009)

Yes. Using loop w/ short-n-sweet hook.


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## Roskoe (Apr 15, 2007)

Are you sure the tear you are getting is "nock high"? You have the three legged hole made by the fletching and then a dog leg tear going down from there? If you don't have clearance issues, I would substitute another rest (QAD Ultra HD would be a good one) and see if that changes things. And the arrow thing is kinda goofy. You get a bullet hole by going down to a 65 gr. tip, which considerably stiffens the arrow. And you also get a bullet hole by dropping the draw weight, which makes a weaker arrow better suited to the bow. So it would be logical to conclude that, for some reason, this bow wants a stiffer arrow. I would also try running a stiffer shaft (shorten one of your arrows by about 1.5" to 2") and see what happens. There are some things in bow tuning that come under the category of "it is what it is".


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## Hoyt Thompson (May 7, 2007)

Could be that the tension is too light on the rest. maybe.

You mentioned the cam could be out of time and this could cause various up and down tears.

A solocam is esecially two cams fused into one. So if it is at the proper starting point at brace then the "cams" are set. if it is over or under rotated then one side of the cam is already ahead of the other side of the cam, if that makes sense to you.

Mathews forums have several tuning threads that are fairly easy to follow with pictures.


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## red44 (Apr 11, 2005)

How are the cam orientation holes and is the arrow bysecting the berger hole?


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## Dan'l (Feb 4, 2009)

Roskoe said:


> Are you sure the tear you are getting is "nock high"? You have the three legged hole made by the fletching and then a dog leg tear going down from there? If you don't have clearance issues, I would substitute another rest (QAD Ultra HD would be a good one) and see if that changes things. And the arrow thing is kinda goofy. You get a bullet hole by going down to a 65 gr. tip, which considerably stiffens the arrow. And you also get a bullet hole by dropping the draw weight, which makes a weaker arrow better suited to the bow. So it would be logical to conclude that, for some reason, this bow wants a stiffer arrow. I would also try running a stiffer shaft (shorten one of your arrows by about 1.5" to 2") and see what happens. There are some things in bow tuning that come under the category of "it is what it is".



I'm trying to accept the "it is what it is" if I can get it right. I've never had problems tuning with a golden premier. Several keep saying spring tension may be too LIGHT. Easton Tuning guide says REDUCE tension in response to nock high. I've gone as light as will hold up the arrow and gone tight. Tight makes tear worse. It is nock high. Hole goes in vanes tear above point entrance hole. 

Took 1.25" off arrows. Can't take anymore. Made tear slightly better. Still can't understand how a 28.25" 7595 can be underspined w/ 100 gr point @ 68#.

Response to cam timing is. I twisted the string, which of course moved the top timing hole closer to the riser (about 1/16th or 3/32th closer than bottom hole- from parrallel w/ string). This in turn also raised the nock point. Still nock high. I lowered NP back down. (Yes arrow goes through berger button.) This improved the tear and can get paper tune close with only one turn off limb bolts instead of two(i.e ca. 65#). SO, I guess the timing change helped. However, I know this is "OUT of TIME". Shifted over to broadhead tuning to fine tune. BH's about 3.5-4" below FP @ 30 yds. NP -3/16" and I'm NOT lowering it any further. It already looks uphill. Took a half turn off bottom limb. Made worse. Put it back. Took 1/2 turn off top limb. BH's 1-1.5" below FP. I guess I'm headed in the right direction. or am I?

I'll gladly start all over if somebody has the silver bullet to get this thing in-tune the right way. Or should I just keep going whatever it takes and accept that "it is what it is". Also figure I'll bite the bullet on some 7595-07's and see if it spine. That just doesn't make sense.

Thanks for everybody's help.


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## red44 (Apr 11, 2005)

I was going to suggest a couple UNTWISTS of the cable, but you twisted the string, same difference. A 75/95 is still just a 340 spine so you are'nt too stiff.
I'd start with the limbs set the same, if rest tension is no help, there is the limb bolts, and I don't think they should be miss-matched, keep them equal turns out, or in. How high nock have you gone to eliminate the possibility of a bounce up? Do you have any stiffer/weaker shafts to try?


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## TMan51 (Jan 25, 2004)

Dan'l said:


> My last resort has been messing with the cam timing. Can anyone tell me if an over or under rotated cam would cause nock high. Which? I've made some adjustments in both directions but have not seen an appreciable difference.


I find that my style requires an under-rotated top cam to get good nock entry. With my top and bottom cams timed "perfectly", I get a nock high tear no matter what arrow, or rest height I use, with the nock set to square.

If the nock is below square, and you're still nock low, it's probably a timing issue. You don't mention the type of rest you're using, but timing on a drop away can cause problems. ? I've never seen much effect for tension on any of my QT rests. But I always try for spine at the stiff end, and that may be why. But the 7595's are not underspined at 68lbs, even from the heavier bows and longer arrows my friends use.


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## dtrkyman (Jul 27, 2004)

adjust the spring and see what it does that is the first thing i would do,you may be getting a bounce off the rest due to not enough tension.go way to the stiff side on the spring and see if it changes.


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## nelliott (Feb 22, 2008)

To keep it short and simple. Ive played around for hours with some of my bows on paper tuning and I was told by another guy that carbon arrows with lie to you. Did the reverse off what the books said I should do and got a bare shaft bullet hole in a matter of minutes. Might want to give it a try.


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## dmbang (Aug 20, 2007)

*Cam timing, paper tuning, all that stuff*

I am a techno geek I've been told. I shoot Mathews because of their simplicity of tuning. I don't believe you can "untime" the cam. There is a right and wrong place but nock travel will not change. When you rotate the cam more or less, you just adjust the efficiency of the cycle, not timing. Rotating the cam can't get out of sync as they are welded together. THere is no cam timing issues with a single cam. Thus it's simplicity. What I see happening is that because you have the nock low to begin with, the rest kicks the back of the arrow up as it passes giving you nock high tear. A fall away rest won't do this ususally but even then sometimes. I used to spend hours trying to tune my Legacy through paper. Now it takes me literally 10 minutes. First I ignore paper tuning. I have absolutely no use for it as it isn't necessary if you follow these steps. I shoot an unfletched arrow to determine nock position up and down. If your unfletched arrow will shoot parallel to a fletched arrow, your nock is right on. Then I do a walk back tune for center shot using fletched arrows. I start at 10 yards and get pins on line. I then move out to 60 yards and adjust rest so that I get the same line as at 5 yards. Shoot 3 arrow groups back and forth. Adjust your rest in and out until it's perfect. You can check arrow spine by shooting unfletched arrows at 15 yards or so after the nock tuning and walk back tuning. 
Remember that you have automatic torque caused by the cable guard so your center shot has to be adjusted by you, no one else holds your bow before and after the shot like you. Form is everything after that. Be sure your drawlength is not to long or short and it will all come together. Good luck and hope this helps. It sure is simple now and no more hair pulling, at least for me.


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## Dan'l (Feb 4, 2009)

I want to thank everyone for their input. Mystery solved, kind of. The long and the short of it is that despite making every conceivable change to the bow setup from cam timing, nock position, rest position, rest spring tension, tiller, arrow spine, arrow length, poundage, etc., I switched from the prongs on the Golden Premier to a blade launcher and with 1 adjustment had a bullet hole with both my 5575 and 7595 shafts. Further, all of the adjustments that seemingly made little difference in correcting my previous problem barely make a difference in the bow not shooting a perfect hole. Broadheads and field points shoot same point of impact. This is more like what I'm used to. I guess this all attests to the solocams ultimate forgiveness.

It is hard for me to speculate what difference the blade laucher made over the prongs. The obvious assumption would be that I had fletching contact, but I had extensively powder tested and could not see any signs of contact. Maybe I missed it or maybe the mystery lies somewhere else.

I think the lesson to be learned here is that when things don't make sense, go down a different road. Thanks again to all who offered help.

"Insanity is doing the same thing over and over hoping to get a different result."

Good shooting and God bless

Dan Hammond


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