Prime Centergy Tune

[92xj]

Prime Centergy
70lbs on scale
28.5" draw length
28" arrow carbon to carbon
300 BE Rampage
150gr head
50gr insert
25gr collar
3 fletch with wrap
Right hand

I have shot this bow great for the past few years. Changed up the arrows this year and shot all summer. Decided to throw the broad heads on and was hitting a few inches left.

Decided to start by paper tuning with field points.
Tear is slightly down and to the right.

I have moved rest to the left as far as it goes, no change in right tear.
Adjusted flexis arm everyway possible, nothing.
I cannot get this right tear out of it.
I went as far as ordered some 350 BE arrows to try to lower the spine, but I don't feel that will help with so much weight up front. They should be here in a few days and I will build and shoot.

I have changed my grip from not gripping at all to grabbing on like my life depends on it, no change.

What else can I tinker with to get this right tear to straighten up?

 

[Samdemarais]

I struggled with this for a while with this bow. I just think it likes a weaker spine then you would think. I moved to 350 spine 175 up front and arrows fly great. Pic below is 60 yards and one is an iron will. I would get the 350s and 2 up with field points and one for broadhead. If it ends up being slightly weak then all you would have to do is drop a lb or two of poundage or cut arrow slightly shorter. Also I had to set my rest at 29/32.

 

[OR Archer]

Before you worry about the right left I would fix the nock low first. It may help clean up the left right issue.

 

[92xj]

Where are you riding the shaft through the berger hole?

 

[92xj]

Before you worry about the right left I would fix the nock low first. It may help clean up the left right issue.

The low is very tiny. I plan to move the nock up a tick tonight and see what happens. I already moved the rest down a tiny bit and don't want to go any lower with it. The right tear is over an inch, the down is under a quarter.

 

[OR Archer]

If it’s nock low you could be getting contact which could make the left right issue look larger than it is. That’s why I always correct for nock height before left right.

 

[OR Archer]

Also grip pressure is huge with the Primes. You may need to play around with that. A slight adjustment can go a long way.

 

[Mighty Mouse]

If you haven't done so already, I'd recommend putting your arrows on a spinner to visually check for good alignment between the shaft and broadhead. It may also be worthwhile to try BH's on multiple arrows to make sure the BH vs. FP pattern is consistent and it's not just a straightness/concentricity issue with a particular arrow. I'd be surprised if overspine is the root cause; 300 seems like a good choice for that amount of point weight on a 28" shaft at 70#.

 

[92xj]

Also grip pressure is huge with the Primes. You may need to play around with that. A slight adjustment can go a long way.

Roger that.

What is the optimal location of shaft vis berger hole? And are you finding a nock high of 1/8 a solid location?

 

[92xj]

Also grip pressure is huge with the Primes. You may need to play around with that. A slight adjustment can go a long way.

If you haven't done so already, I'd recommend putting your arrows on a spinner to visually check for good alignment between the shaft and broadhead. It may also be worthwhile to try BH's on multiple arrows to make sure the BH vs. FP pattern is consistent and it's not just a straightness/concentricity issue with a particular arrow. I'd be surprised if overspine is the root cause; 300 seems like a good choice for that amount of point weight on a 28" shaft at 70#.

All spin great with broadhead and field points. Running all iron will components. Tried 2 different broadhead on 3 shafts. And I agree about your spine comments. I just don't know what else to try, so figured I'd get the 350s a whirl.

 

[OR Archer]

Upper half of the Berger is where I prefer to start on the Primes.

 

[cured_ham]

I shot a Centergy last year and am shooting a Black 5 now. Grip torque is a thing with these bows it seems. I could not tune out my torque on either of those bows. They shoot great but tuning has been a nightmare. Best thing I found to do was move stabilizers around until you minimize the grip torque.

I would never have thought that it would make a difference but it was the only way I could get a good tune.

 

[HoytHunter24]

I ran in to this same issue with my centergy hybrid. I discovered that Prime bows are very picky about grip pressure. Once I figured that out (without changing anything else on the bow) I started shooting bullet holes. It really opened my eyes to how much your form and grip can effect your shot. Set your center shot and then work on grip and see how much it changes.

 

[Billy Goat]

How can you be certain it's grip torque and not face pressure?

A different grip might fix it, but only because you finally found the grip that perfectly countered your face pressure.

That might be why they are so picky. I haven't messed with any, I just keep reading about grip pressure and find it hard to believe the grip is truly that sensitive.

 

[92xj]

I tested the face pressure thought last night. I shot 10 shots with my normal points of contact and pressure and 10 shots with the string not touching. I would come to my normal anchors and then pull my face off and shoot. 20 of the exact same tears.

I did play with grip changes, and it moved the tear around a little and got some good looking holes. I don't like this though as I can't determine if my center shot is perfect and the arrow is coming off perfectly because I am torquing the grip which hides the arrow flight and makes a good hole. If that makes any sense.

 

[wesfromky]

Have you watched this video? Thought it was pretty good.

Prime Centergy In Depth Tuning video

It's about 20 min long but some good info for the DIY guys. Prime Centergy - YouTube Sent from my iPhone using Tapatalk

www.rokslide.com

Also, seems like grip is important, as mentioned above.

I was getting a nock low tear, with bareshafts hitting kinda high, adjusted my rest and my grip a bit and they are hitting together now. IW wides hit with field points.

 

[MHB]

Couple of things,

1) Assuming you are right eye dominate, hold the bow in your left hand and release in the right?

2) Have you checked timing? This could cause the vertical tear you are seeing.

3) A 350 (Hoping this was a mistype) is too weak for your setup and point weight. If you are trying to get a stiffer spine you would want the 250 not the 350.

4) Has anyone else shot your bow through paper? I ask because a friend of mind was have issues with his bow (different brand). He brought it over, we set the center shot and I could shoot a bullet hole. While I watched him he was shooting bullet holes too. When he got home he had the tear again. This boiled down to a form issue on his part. We are working through this.

Both my primes have always tuned right down the center (Looking down the limb bolt to stabilizer). I put the center of the arrow shaft in the center of the burger hole. I am using a drop away rest. The flex arm is bottomed out.

 

[Niceandkozy8]

I have a similar issue with same bow, poundage and draw weight. I found that if I put my rest at 7/8 backed out the flexis to 2-2.5 turns and I dialed in my grip (this was the most important part for me) I can shoot bullet holes. I found that grip pressure/torque was the biggest factor. It seems this bow requires a very specific grip placement as a lot of other people have mentioned previously.

When you get all of things dialed in the bow is an absolute shooter. But it did take some tweaking for me to get there.

I also noticed when I tried a 3 fletch I would get fletching contact periodically, when I switched to a 4 fletch it never seems to happen.