Peoples experience is all over the board on carbons. In the end you have to work this out for yourself and your bow. I can offer some of what I have found. I don’t know if it will help or confuse you.
I to have had all kinds of odd tuning issues with carbons. For me the 5575 acts much stiffer than the spine would indicate. However, the 3555 acts about right for me. I shoot about 50-52@28 with a little over 29” draw. I can’t cut 3555’s much because I think they are 30” plus nock length. I get them down to about 8 gpp and cut as short as I can go, and they are still a little too weak. I have had them flying way weak and brought them in by reducing point weigh. No doubt for me they are too weak. Unless I am shooting ILF I just can’t stiffen them more by dropping point weight.
Odd thing I find is that a cut to center bow for me likes to shoot a stiffer carbon than a cut past center bow of the same draw weight. It should be the other way around, but as far as I can tell the fast recovering carbon and the more spine forgiving cut past center bows just seem get along well and work out better with a little less spine.
I have a theory that a carbon due to its fast recovery could have two ranges it can work in for spine. One is on the stiff side where the arrow flexes a little and recovers very fast. You can tune it. The other option is real weak where the arrow flexes a lot more, acts more like wood or aluminum and flexes a couple times before final recovery. Between the two is a place where things get sketchy and probably look weak for a while until you get enough flex for a good rebound flex back. Not sure as I have not gotten that weak with anything I have tested, but I suspect it based on what other have been able to do.
For the 5575 I have to run my arrows about 31”, add 100 gr. insert and then about 150-175 points depending on the bow. For me that is about 20# under spine from what Stu’s calculator says. One thing I have seen stated, and it works out for me, is that carbons are much more sensitive to length than to point weight. I have two shaft of the same spine with two lengths and point weights. The dynamic spine is off about 5# with the shorter shaft being the weaker of the two. Both bare shaft great and the same flight, fly great fletched, and shoot great with a broadhead. I have tested them with point changes and just end up the same. The shorter shaft must have more point weight proportionally or a weaker dynamic spine number in comparison to the longer shaft to work. Length is critical and probably why some people can really load up a lighter spine shaft. I think you take off an inch or two and get a big difference.
I am not sure what happens with the 7595, but if it increases dynamic spine as much as the jump between the 3555 and 5575, I would guess you are too stiff. I would really load up the point weight if you can. Go 100 gr. insert and 200 or 225 and see what happens. Better yet start off with a 31” shaft or longer and work down. I think you could make that shaft work for you if you get the length and weight up. Something like 31” plus with 100 gr. insert and 175-200 point. This would give you a little over 10 gpp.
You can try the 5575, but you’re shooting a 62-63# bow at your draw weight. Based on my experience with that bow about 10# lighter draw would indicate you could end up a little too weak when you hit the bottom of the recommended gpp range. You can build out the strike plate to try to get it, but you still may not get much if weight if you want it without jumping as shaft size.
A test kit and point weight test kit is the only way to fly I think. Good luck and keep us posted.
Topic: Weak or waaay too stiff? (Read 502 times)
