How can an Arrow be over spined? I understand how it could be underspined. Not being able to handle the torque of your draw wieght but what negative effect would you have with a spine that is too stiff? Would you want to jump up a spine deflection lets say from 340 to 300 if your adding alot of wieght to the tip of your arrow. Like 100 grn or more insert plus 125 grn heads? wouldnt you want your spine to be stiffer in order to handle the extra wieght pushing back against your shot?
There is less negative effect to be overspined than being underspined. Slightly overspined is actually good for hunting. Too overspined can have a negative effect on energy transfer from bow to arrow though. Yes.
OK refering to my second question. Is there a chart for selecting spine deflection that includes arrow tip wieght with the poundage you draw? Or is this a best guess sort of thing, Like move up one spine deflection on the chart if you plan to do it?
No chart but there is software if you are so inclined. I would say, though, that most 70# bows wanting to use a 125 grain tip would be good with a .340 spine. With that spine there are multiple adjustment or arrow setup options to get set up with tips anywhere from 100 to 150+ on 70# bows.
I would be very interested in computer software that allows you to punch in a few numbers and watch an arrows dynamic? very cool!
Here is the chart i used when finding the right spine for my arrows based on DL, DW and tip wieght. http://www.huntersfriend.com/carbon_arrows/hunting_arrows_spine_chart_by_deflection.htm Notice that if you want to be overspined you would need to move down the chart a little.
