Mathews paper tuning issues.

[stone1]

Afternoon everyone.

I recently purchased a Mathews z7 and have been tuning it probably for the last 8 hours...

I've set everything up, drop away rest at 13/16ths, nock slightly above level, my idler wheel comes perfectly aligned when I am at full draw in my anchors, peep is the correct height and I shoot often so I have correct anchors and such.

While tuning I keep getting a nock left tune. I've adjusted my rest as far as possible right (there is still about a quarter inch left to adjust my rest but the housing runs into my cable guard). I'm shooting a truglo drop away if that gives you a better idea.

This is not the first bow i've tuned; my previous was a bear authority and while it did give me trouble it was because I was underspined. Once I purchased the correct arrows I never had issues. Now with my Mathews bow i'm running into the nock left issue.

My Mathews is definitely faster that my Bear but the arrows i'm shooting are pretty damn stiff and heavy.

Bear authority was 315 fps(ipo) pulling 68lbs at 29in draw

Mathews z7 is 330fps (ipo) pulling 67lbs at 29in draw.

Arrows are 300 spine bloodsport Micro diameter. 11.7gpi cut to 28inches. 100 grain field tips.

Anyone who may have an understanding of what my issue could be please feel free.

Thank you!

 

[kyler1945]

Afternoon everyone.

I recently purchased a Mathews z7 and have been tuning it probably for the last 8 hours...

I've set everything up, drop away rest at 13/16ths, nock slightly above level, my idler wheel comes perfectly aligned when I am at full draw in my anchors, peep is the correct height and I shoot often so I have correct anchors and such.

While tuning I keep getting a nock left tune. I've adjusted my rest as far as possible right (there is still about a quarter inch left to adjust my rest but the housing runs into my cable guard). I'm shooting a truglo drop away if that gives you a better idea.

This is not the first bow i've tuned; my previous was a bear authority and while it did give me trouble it was because I was underspined. Once I purchased the correct arrows I never had issues. Now with my Mathews bow i'm running into the nock left issue.

My Mathews is definitely faster that my Bear but the arrows i'm shooting are pretty damn stiff and heavy.

Bear authority was 315 fps(ipo) pulling 68lbs at 29in draw

Mathews z7 is 330fps (ipo) pulling 67lbs at 29in draw.

Arrows are 300 spine bloodsport Micro diameter. 11.7gpi cut to 28inches. 100 grain field tips.

Anyone who may have an understanding of what my issue could be please feel free.

Thank you!

Assuming you mean 300spine?

What weight inserts?

I think you’re probably overspined. I’d be curious if you went back to center with a 150 or 200 grain field point how it behaved. If it starts acting right, you’re probably overspined. If you were shooting a more typical weight shaft (7-9) gpi, you might get it right with a 300 spine.

I shoot 300 spine 28.25” c2c 510gr with a 70/30 bow. But I have 225 grains up front between insert and broadhead.


I’m no bow expert though. Just played this game with very similar bow specs. Ultimately when I was in a 340 spine I could tune with 145grains up front. When I went to 225, I stepped up to 300 and that was the ticket.

 

[Wirrex]

Probably a spine issue. It really doesn’t matter what your old bow shot. Every bow is different. You can make bad arrows hit a spot by adjusting the bow but it doesn’t mean the bow is tuned to the arrows. That’s why I start with a bareshaft.

 

[stone1]

Assuming you mean 300spine?

What weight inserts?

I think you’re probably overspined. I’d be curious if you went back to center with a 150 or 200 grain field point how it behaved. If it starts acting right, you’re probably overspined. If you were shooting a more typical weight shaft (7-9) gpi, you might get it right with a 300 spine.

I shoot 300 spine 28.25” c2c 510gr with a 70/30 bow. But I have 225 grains up front between insert and broadhead.


I’m no bow expert though. Just played this game with very similar bow specs. Ultimately when I was in a 340 spine I could tune with 145grains up front. When I went to 225, I stepped up to 300 and that was the ticket.

Yes I edited spine after I reread my post.

I shot a 350 spined arrow with a 100grain tip and the nock left tear was even more dramatic.

My outserts are 40 grains. I don't have heavier tips on hand to test that theory but I appreciate you're thought.

What's interesting is my Bear; which was a slower bow, shot the same arrows and was able to paper tune bullets.

 

[stone1]

*Update*


I seemed to have fixed the tuning issue and i'm now getting bullets with bareshaft and fletchings..

I added two twists to string to bring draw down a little and added 4 total twists to my left yoke. Opposite of what you'd think as it's single cam, but I saw another forum where it is a common issue for the Z7 and that's the fix.

Thanks

 

[kyler1945]

Boom! Thanks for the update. Tucking that away.

 

[Jrybicki]

Glad you got it figured out youll love the z7 at least I love mine amd planning on keeping it even when I decide to go all in on a whole new setup. Right and left tears assuming your spinned correct is usually always rest issue or yoke twists. Glad you figured it out quickly, took me a couple days to fix mine lol I ran accross a tuning chart/youtube video a few years ago that covered each type of tear and common causes for that particular tear... wish I could remember where it was as it was a super helpful tuning reference.