# Nock low tear. Am I under spined?



## RxBowhunter (Feb 16, 2005)

70# Ross Cardiac maxed out. I don't have a scale so I haven't measured the exact draw weight.
29 inch draw length
Easton ACC 3-49 cut to 29 1/4" nock throat to end of shaft. 100gr field points with inserts.
Drop zone rest

I am consistantly getting a nock low tear. If I "tune it" to get a ~~clean hole thru paper, the arrow sits very point low at full draw.........about 1/4 inch above the shelf.

I know the exact draw weight would help, but with an estimated max wt of 
68-72#, can we get some guesses?

I am thinking;
1. Reduce draw weight by ~1 turn. I hate to lose draw weight as I am hunting elk in August and want the most KE I can get from the bow.

2. Cut an inch from the arrow shaft. That would stiffen it some.

3. Reduce point weight to 85 grains.......again adding stiffness. 

Maybe a combination of 2 and 3?

Any guesses?


----------



## phumb (Oct 7, 2006)

I'm no pro at this but my 1st 2 thoughts are -although spine can be important, its usually left and right concerns, not up n down. 2nd, if your arrow is only 1/4" off the shelf, how can you possibly get fletch clearence? If you really think your underspined, lower poundage, you don't have to keep it there, just see if it helps. How do broadheads fly? I'd be more concerned about that then paper...


----------



## bassman409 (Jul 19, 2006)

The Easton chart says you should be shooting those arrows at 60 pounds. I would cut them to 28 inchs . I would then take a broadhead at 40 yards and see where it hit compared to your FPs. Adjust your nock to make them hit the same. Try to keep the arrow across the berger hole at full draw.


----------



## RxBowhunter (Feb 16, 2005)

phumb said:


> I'm no pro at this but my 1st 2 thoughts are -although spine can be important, its usually left and right concerns, not up n down. 2nd, if your arrow is only 1/4" off the shelf, how can you possibly get fletch clearence? If you really think your underspined, lower poundage, you don't have to keep it there, just see if it helps. How do broadheads fly? I'd be more concerned about that then paper...



I didn't think I made that clear when I typed it. If I raise the drop away rest with an arrow nocked, the portion of the shaft above the shelf is ~ 1/4 inch above the shelf **when I get close to a clean hole in paper** during tuning. It is clearly wrong and I'm not leaving it there. 

I am no pro at this either.........or I wouldn't be writing this thread lol..........but I think I remember reading somewhere that left and right tears may indicate a spine problem with a conventional rest and nock high and low tears may indicate a spine problem with a drop away rest. 

As far as broadhead flight?..........I always start with a clean shooting arrow first then tune or adjust where needed for good broadhead flight so I haven't shot a broadhead yet.


----------



## RxBowhunter (Feb 16, 2005)

bassman409 said:


> The Easton chart says you should be shooting those arrows at 60 pounds. I would cut them to 28 inchs . I would then take a broadhead at 40 yards and see where it hit compared to your FPs. Adjust your nock to make them hit the same. Try to keep the arrow across the berger hole at full draw.


Thanks bassman. I'll try that when I pick up the bow on Thursday. I took it to the local shop yesterday to let them play with it. The man who was working there worked on it for about 3 hours and decided to leave it for the owner to try to get a second (or third) opinion. They are closed today.


----------



## Brown Hornet (Aug 8, 2002)

RxBowhunter said:


> 70# Ross Cardiac maxed out. I don't have a scale so I haven't measured the exact draw weight.
> 29 inch draw length
> Easton ACC 3-49 cut to 29 1/4" nock throat to end of shaft. 100gr field points with inserts.
> Drop zone rest
> ...



Your arrow is weak but that is not why you are getting a low tear. Lower your nocking point so that it is just barley above level. I think what you are seeing is your arrow porposing up and down. The reason I say this is because if your point is obviously on a down ward angle there is no way you should be getting a low tear.

That being said......to get you arrows to spine.....drop your weight down to 66-67lbs (trust me the Elk won't know the difference, plenty of people shoot them with a lot less weight). Cut your arrow to 28" and a wrap to your shaft if you don't already have them. You can drop your point weight to 90 grains and all of the above will give you a perfectly spined arrow.

Of course this won't mean squat if your bow isn't setup and tuned correctly. SO work on that first.:wink:


----------



## 454casull (Jan 7, 2005)

*I had a similar issue. Be careful.....*

With my older equipment, 92 Hoyt SuperSlam. After installing a LD Pro I could not paper tune out a low tear no matter what I did. Yes it is timed correctly. I ended up taking 1.5 turns out of the lower limb bolt and the tear went away and shot bullet holes w/ bare or fletched shaft (@8ft). Fast forward to the range. Walk back had me move the rest slightly to the left (I'm a hook) so the center shot is on. However I was struggling to get tight and/or consistant groups and it was really bugging me. I had made multiple changes and thought that I was the issue. So out of desperation/curiosity I put .5 turn back into the lower limb bolt...50% group improvement. I stopped for the day due to fatigue. The moral here is while paper gets you close and lets you know how the arrow is leaving the bow, it is not the end all. Get it close then get to the range.


----------



## TMan51 (Jan 25, 2004)

If you have a chronic low tear from a nock set to square with the string, the lower cam is over rotated/out of time. It's still turning after the top cam has reached it's resting position, pulling the nock down as the arrow leaves the bow.

Rest tension (on a prong type rest) will affect this slightly, but adjusted for proper height, the arrow has very little contact with the prongs as it flexes on release. Usually not the problem. On a drop away, rest height at full draw can affect arrow travel, but you have to be pretty far off to be a problem.


Check your cam timing.


----------



## RxBowhunter (Feb 16, 2005)

TMan51 said:


> If you have a chronic low tear from a nock set to square with the string, the lower cam is over rotated/out of time. It's still turning after the top cam has reached it's resting position, pulling the nock down as the arrow leaves the bow.
> 
> Rest tension (on a prong type rest) will affect this slightly, but adjusted for proper height, the arrow has very little contact with the prongs as it flexes on release. Usually not the problem. On a drop away, rest height at full draw can affect arrow travel, but you have to be pretty far off to be a problem.
> 
> ...


This is correct for a two cam bow.
The Cardiac is a single cam system with an idler wheel. I have the cam adjusted to perfect timing and tiller is even. 

Brown Hornet and 454;
Good advice there guys and thanks. 
I have adjusted the tune infinately as has the man at the shop. I am 90% sure it is a spine issue and will do all the above to increase spine starting with decreased point weight to 86 grains and cutting an inch off the shaft. If that doesn't do the trick, I will decrease draw weight until I get a clean hole. 

To me, the clean hole thru paper is my STARTING point in getting the bow to shoot broadheads well. I will finish the tuning process at the range as mentioned above. 

Thanks again guys,

Rx


----------



## TMan51 (Jan 25, 2004)

Ah, OK,

Keep in mind that wrist and grip angle can affect the perfectly timed/tillered single cam.

I shoot with a high wrist grip, and had to adjust my "Redlines" with a bit of advanced cam to get good entry from a bare shaft, and good broadhead flight. But I've had other shooters say the exact opposite.

As a check. Take two turns out on your cable, or string, set the nock to square, and see if it gets better. If worse, go the other way.

Sometimes that puts a fix in the problem.


----------



## kyost (Aug 16, 2004)

If you get the issue worked out with a stiffer spined shaft, great for you. I will say on my four Mathews bows, I get nock low through the paper with a .300 spine shaft with the cams in the proper rotation.

And as far as adjusting limb bolts to get better tears through the paper, keep in mind that, on a single cam, all you're doing is moving the nocking point one way or the other.


----------



## RxBowhunter (Feb 16, 2005)

kyost said:


> If you get the issue worked out with a stiffer spined shaft, great for you. I will say on my four Mathews bows, I get nock low through the paper with a .300 spine shaft with the cams in the proper rotation.
> 
> And as far as adjusting limb bolts to get better tears through the paper, keep in mind that, on a single cam, all you're doing is moving the nocking point one way or the other.



Are you shooting fixed blade broadheads with that setup and the nock low tear? If so, how are they flying for you?

The nock point does move slightly when the limb bolt is adjusted but the change in draw weight is what changes the dynamic spine of the arrow.


----------



## 454casull (Jan 7, 2005)

*Same w/ twin cams.*

Kyost, Same thing with a two cammer, perhaps to a lesser degree but I have ZERO experience with single cam bows so I'll defer to those with more hands on. All I know is that it worked to get rid of about a 1" tear but the groups were poor and not too consistant. 
RX, I also when from a 340 spine to a 300 and it made absolutely NO difference (tear wise)with my setups. I have two nearly identical SuperSlams and both reacted the same way to the tiller adjustments. I'm guessing nock travel wasn't high on the priorety list in "92".


----------



## RxBowhunter (Feb 16, 2005)

*Definately underspined*

The 3-49 was definately underspined for the 70 pound draw (measured it today) Cardiac cam. 

I tried my CX Maxima 350's and they flew perfect with field points and fixed blade broadheads. Out to 50 yards I noticed no change in my groups with the FPs or BHs. 
That's what I'm talking about right there!:thumbs_up:thumbs_up

I've shot these acc 3-49s with my Outback, Switchback XT and my old Bengel. They flew just fine with those bows all set around 70 pounds.


----------



## 60Xbulldog60X (Mar 12, 2005)

What I have found with the single cam bows is that with the nocking point set just slightly above 90 degrees, if you are getting a knock high tear it indicates an underspined arrow. If you are getting a nock low tear it indicates an overspined arrow. While shooting through the paper, it needs to be done as close to the paper as possible for a starting point. This will give you a good indication of what the arrow is doing when it first leaves the string.


----------



## Adlautz (Aug 11, 2018)

RxBowhunter said:


> 70# Ross Cardiac maxed out. I don't have a scale so I haven't measured the exact draw weight.
> 29 inch draw length
> Easton ACC 3-49 cut to 29 1/4" nock throat to end of shaft. 100gr field points with inserts.
> Drop zone rest
> ...


Usually that’s because you have too much nock travel. Your cams are out of sync


----------

