determining spine

[michael kavouklis]

How do I determine the correct spine that I should be shooting out of my bow? I want to shoot cedars out of my 60# bear grizzly. Also, does the correct arrow spine for a particular bow vary depending on the wood?

[Bjorn]

Go to the Morrison or ACS bows, site. Or do a search here. Or better yet, get a hold of Ted at raptorarchery.com he is a sponsor here.

[aromakr]

Mike:
Several factors need to be addressed to calculate spine. The bow weight is just one of them. Also will need to know what your draw length is and how long you wish the arrows to be, measured from the bottom of the nock groove to back of point. Then how deep the shelf is cut, i.e. less than center, center, past center.
Bob

[outbackbowhunter]

Find a carbon or alloy arrow size that shoots well from your bow, for arguments sake, lets say a 2117 alloy or 55/75 carbon.

They have a spine rating around 400 deflection.

Your cedar shaft supplier should then be able to select shafts with 400 spine deflection rating for you.

Its been a long time since I have used cedars, but I had found that if you ask for a 10 to 15 pound heavier spine rating, it worked out about right.

For a 60 pound bow I would try about 70/75 spined cedars. For some reason, the rated spine figure always worked out a little weak, and a stiffer spine was better.