Stu's calculator - what am I doing wrong

[EHK]

I'm trying to spine surewoods for a current version 45# grizzly.  I draw 29" and would like to put 145 up front.  When I put this into Stu's, it's coming up with about an 80# spine for the shafts.  Am I doing something wrong?

 

[Tim Fishell]

I am still using one of last years versions but when I run the numbers I come up with a 67# spine and the numbers come out almost dead nuts.

[Flying Dutchman]

You are doing everthing right but one: the diameter of your shafts. The box is saying  "0,034" and it should be "0,344" (assuming you use 11/32). The cause is probably that you can't see what you are typing when working in that box.
Let me know!

[EHK]

Many hanks to both of you.  Dutchman, I can't tell you how many times I've input that .034 instead of .344.  Damn computers - always doing what you tell them to do!

[Flying Dutchman]

Yeah, I hate it too when that happens!
Now tell me what your new outcome is???

[EHK]

calling for 72# spine with the correct diameter in there.  Not as high as before, but still higher than I would have expected for that setup.  I do have 65-70's that I'll play around with before jumping up to 70-75.  I'll let you know what I find out.

[Flying Dutchman]

I think a 72# spine is pretty accurate here. You have a long lenght (30 inches back of point to nock groove) and a 145 grains point.
But you are right, first try out what you have! You can also lower your point weight to see what happens!