I really don't understand arrow spine too much and trying to choose an arrow gets more confusing to me when you can look at 3 different manufacturers charts and each one is a different spine recommendation. So here is my set up, Bear Venue with 50 lb limbs, maxed out. I don't know the exact poundage it is maxed out being I haven't had it checked since I worked up to getting it maxed out. Draw length is 26" I am looking at Gold Tip arrows and they have 2 different charts for different IBO speeds. My Venue's advertised IBO speed is 330 fps. Whether or not I am getting that, probably not. So I am unsure which Gold Tip chart I should be going off of. So my question is, which spine do you recommend for me? If I follow the their charts, one chart I fall under a 500 spine, the other, 400. Also, what length? My current arrows the shop cut them at 26 3/4" from throat of nock to end of shaft. The help is appreciated.
Read the chart based off of your IBO speed, not actual speed. As far as arrow length, go off of the length of carbon you have. I have had the best luck by choosing one box to the right of what it recommends. If you're on the line of .400 and .500 spines and you're picking a hunting arrow, go with the stiffer .400 spine. I just looked at Gold Tips chart on a box of arrows and you're right on the line between .500 and .400, go with the .400's. Stiffer in most cases, is better!
Definitely the 400's. IBO on your bow is 330 fps, you are probably closer to 250-260 fps at 50#. IBO is calculated with using 70#/30" draw length/350 gn arrow. You lose fps for every inch under 30", you lose fps for every pound of draw weight under 70#, you lose fps for every grain of arrow weight over 350 grains, and you lose fps for anything you add to the string (d-loop, kisser button, peep, etc.).
