Arrow spine

[MSU_19]

I’m getting a stiff arrow tear when paper tuning. How do I know if my arrow is too stiff or if I just need to put twists in my string? I used eastons spine chart to determine I needed a 260 spine with my 30.5” draw. My limbs are maxed out at 73lbs. My point weight is 175g and have a four fletch AAE max stealth vanes. Total arrow weight is about 575g.

 

[Gerard Marcaurele]

How long is your arrow?

Is your center shot set at factory spec?

Are your cams timed correctly?

What bow?

Is there cam lean?

 

[KyleR1985]

You’re borderline with that setup. If arrows are uncut you’ll likely be underspined. Try backing the bow down 5lbs and see if the tear improves. If it does, spine. If not, look into the other things noted above.

there’s no harm in going to a 200spine with your setup though.

 

[W1bowo]

You’re borderline with that setup. If arrows are uncut you’ll likely be underspined. Try backing the bow down 5lbs and see if the tear improves. If it does, spine. If not, look into the other things noted above.

there’s no harm in going to a 200spine with your setup though.

+1

 

[Ucsdryder]

You’re definitely not over spined. You should be fine, adjust the bow and rest.

 

[Jimbob]

The idea of a stiff tear or weak tear is kinda obsolete for modern compounds, don't paper tune with those directions.

You want to get perfect lateral and level nock travel.

For level nock travel, make sure your cam timing is good then adjust rest height, might need one cam slightly advanced when fine-tuning.

For lateral nock travel, you want to set rest center shot (different depending on the bow but 3/4" or 13/16" is good for many) then adjust yokes/cable guard/shim cams to get a bullet hole.

If none of that will give you a bullet hole then maybe spine is the issue.

 

[Mighty Mouse]

Without knowing your actual arrow length, it's hard to say if you're spined correctly. But I'd guess you're pretty close at 260, maybe a bit on the weak side.

You said "stiff" tear...which direction is the nock tearing relative to the point: left/right, high/low, combination? I'm of the opinion that your arrows can't really be "too stiff" with a compound bow and that a wide range of spines can be tuned to fly well.

I've not heard of anyone using string twisting as a method of tuning arrow flight. Adding twists to the string will decrease draw length and weight, which in a roundabout manner could help correct a weak tear (if inadequate spine truly were the cause). Cables can be twisted to adjust cam timing issues that could cause high/low tears. Yoke legs can be twisted to adjust cam lean that could manifest itself as left/right tears.

I'd recommend the following approach:
1) get draw weight, axle-to-axle length, and brace height as close to spec as possible though string/cable twisting
2) adjust cable twists to get cams in sync
3) adjust nocking point & rest elevation to get the arrow running level through the Berger hole
4) adjust rest windage to achieve recommended centershot measurement (usually 13/16" from riser to center of arrow)
5) paper tune at 6' using at least 2 different identically-configured arrows, twist nocks to different orientations if the arrows aren't all tearing in the same direction
6) make adjustments per the diagrams below (originals here: https://www.goldtip.com/Resources/Tuning-Assembly/Paper-Tuning-(1).aspx), fix vertical tears first then work on horizontal

 

[MSU_19]

How long is your arrow?
29.75"

Is your center shot set at factory spec?
I bought the bow used and had the rest set up at a shop.

Are your cams timed correctly?
Not sure I couldn't tell from just pulling it back myself.
I haven't seen it on a draw board or anything

What bow?
Bowtech Realm SS set on sport

Is there cam lean?
I haven't adjusted anything

 

[MSU_19]

You’re borderline with that setup. If arrows are uncut you’ll likely be underspined. Try backing the bow down 5lbs and see if the tear improves. If it does, spine. If not, look into the other things noted above.

there’s no harm in going to a 200spine with your setup though.

Based on the tear I would be overspend. When I shot a 300 spine arrow I was closer to a bullet hole.

You’re borderline with that setup. If arrows are uncut you’ll likely be underspined. Try backing the bow down 5lbs and see if the tear improves. If it does, spine. If not, look into the other things noted above.

there’s no harm in going to a 200spine with your setup though.

Based on the tear I would be overspend. When I shot a 300 spine arrow I was closer to a bullet hole.

 

[MSU_19]

You’re definitely not over spined. You should be fine, adjust the bow and rest.

I tried adjusting the rest and I had to move it so far out of center shot I figured it was the spine or another issue.

 

[Ucsdryder]

What’s the bow and specs?

 

[MSU_19]

Without knowing your actual arrow length, it's hard to say if you're spined correctly. But I'd guess you're pretty close at 260, maybe a bit on the weak side.

You said "stiff" tear...which direction is the nock tearing relative to the point: left/right, high/low, combination? I'm of the opinion that your arrows can't really be "too stiff" with a compound bow and that a wide range of spines can be tuned to fly well.

I've not heard of anyone using string twisting as a method of tuning arrow flight. Adding twists to the string will decrease draw length and weight, which in a roundabout manner could help correct a weak tear (if inadequate spine truly were the cause). Cables can be twisted to adjust cam timing issues that could cause high/low tears. Yoke legs can be twisted to adjust cam lean that could manifest itself as left/right tears.

I'd recommend the following approach:
1) get draw weight, axle-to-axle length, and brace height as close to spec as possible though string/cable twisting
2) adjust cable twists to get cams in sync
3) adjust nocking point & rest elevation to get the arrow running level through the Berger hole
4) adjust rest windage to achieve recommended centershot measurement (usually 13/16" from riser to center of arrow)
5) paper tune at 6' using at least 2 different identically-configured arrows, twist nocks to different orientations if the arrows aren't all tearing in the same direction
6) make adjustments per the diagrams below (originals here: https://www.goldtip.com/Resources/Tuning-Assembly/Paper-Tuning-(1).aspx), fix vertical tears first then work on horizontal
View attachment 199294View attachment 199296

I was using that gold tip tuning chart when I was working on this. Since adjusting my rest didn't give me a bullet hole and got me so far out of center shot I was thinking over spined. It sounds like I just have to go to the bow shop and try some of these other methods to fix my tare since everyone on here seems to agree I shouldn't be over spined.

 

[Mighty Mouse]

I was using that gold tip tuning chart when I was working on this. Since adjusting my rest didn't give me a bullet hole and got me so far out of center shot I was thinking over spined. It sounds like I just have to go to the bow shop and try some of these other methods to fix my tare since everyone on here seems to agree I shouldn't be over spined.

Yep, I'd say take it to the shop and have the cams shimmed over and/or cam lean adjusted if you're getting a stubborn horizontal tear.

Vane contact and nock pinch are also sneaky problems that can cause weird paper tears. If you have a bareshaft, shoot it through paper and see if it tears similar to your fletched shafts. If it doesn't, that could indicate vane contact. The foot powder/lipstick/chalk method can also help diagnose vane contact. Try looser fitting nocks if you think yours might be gripping the string too tightly.