Stu's dynamic spine calculator - question.

[wbyrd]

I'm trying to set up some carbon arrows to use and just wanted to double check my calculation. The arrows I'm using (Victory V6 400) are not in the list of arrows but I was able to get the numbers from the Victory website. The number I'm not sure about is the AMO Static Spine. I'm assuming I want to use the ASTM converter. Correct? So a 400 deflection would be 78.8 AMO Static Spine #.

Just want to double check before I buy the weighted inserts I'll need.

Thanks guys.

[snag]

If you get the deflection off the manufacturer's website you can use this formula for determining spine weight....
 31.5 divided by the deflection = spine weight

For instance I have shot CE 250's that have a deflection of .373
 31.5 divided by .373 = 84.45 spine

[wbyrd]

The manufacturer's website says they are a .400 spine. Does that mean the deflection is .400 also? I'm assuming it does. If so that puts the static spine at 78.75 using the calculation given above.

[sffar]

I've found that, whenever possible, it's good to test the spine on a tester no matter what the manufacturer says. Regardless, you can enter the spine  information you've got in the calculator window (below the bow information) to convert.

[Friend]

Using 78.8 is most likely as close as you are going to get. Of my experience, the calculator works great in most cases of getting you in the ball park for arrows of moderate FOC. There are other factors that may impact your actual arrow flight.

[JimB]

Sorry to confuse things further but I bought a set of Victory V Force HV .300's and they acted a lot stiffer than my Gold Tip .300's.I don't have a spine tester but I needed 30 grs more point weight to tune the Victorys.Shaft length and all other components were identical.The Victory shafts are just a hair narrower in diameter.This may be part of it but I think they may be stiffer as well.I don't know if you will find the same thing with .400's or not.