Arrow Flight Issue
Posted on June 18, 2012
Q: Hi Joe. First off, I just have to say, you guys truly have the best magazine out there. I buy every single new edition I find. Now my tech question for you, which involves bow tuning.
Recently, I purchased a new Mathews Z7 bow. It’s set at 60 pounds at 28-inch draw length. I shoot 28 1/2-inch Carbon Express MayhemÂ 250 arrows with 100-grain tips. The problem I’m having is the arrows aren’t tuning real great; they are shooting left tear and no matter what I do they tear left. Everything I read is telling me that the arrow spine is too weak. I’ve moved the rest both directions and they still shoot left tear. I’ve checked my shooting form and had a buddy shoot it to the same results. Also, from what I’ve read on various web and magazine articles, the center-shot should be 3/16ths left of center. The rest is a QAD HD drop away. Any help would be great. Thanks a bunch.
Harold Price, via email
A: There are two things that are likely causing the problem. 1. Factory center serving is too thick, causing excessive nock friction. Change it out with a smaller size. The arrow nock should just snap on but be free to slide up and down the string. 2. Check for gaps along the axle and cam. It may need a spacer somewhere.
Also, the Slim-Limb bows can be sensitive to cable torque caused by many drop-away rests. You may want to try a rest that attaches to the upper limb (Limb Driver, AAE Pro Drop) to alleviate tuning issues. Otherwise, make sure the QAD rest requires just enough force on the pull-down cord to make it work — nothing more.
A lot of Mathews bows require a center shot very close to the riser, so use a tuning arrow with no fletching on it first until you get a bullet hole in paper. Then switch to a regular arrow (with vanes). To get a clean tear, you may have to twist the nock (change alignment of fletching) to get the vanes to clear the cables and riser. Spray the arrow before shooting through paper to ensure proper clearance.
As a last resort, yoke tune the bow. For tail-left tears, twist up the RIGHT side of the string yoke on the top limb until tear is resolved. Sometimes string angle is the cause of the problem too.
Hope this helps. Thanks for writing in. –Joe Bell