Carbon Tuning

[bucksakemmer]

I am shooting Gold Tips left full lenght because of a 30.5 draw. If I don't want to or really can't cut them down any I use the screw in weights. We know that just cutting a carbon by 1/4 in can change the spine does anyont know how much you would change the spine by adding 20 grain weights? And is this and exceptable tuning method?

[Stinger]

Well they have the opposite affect.  Shortening the shaft will stiffen the spine.  Adding weight will weaken the spine.  Depends on what you are trying to do.  If you need a stiffer spine, but want to keep the length, you probably need to go up a number in the shaft (for example from GT 35/55 to 55/75).

[Cryogenic]

I am no expert but....

20gr weights are reasonable if you are, like Stinger said, trying to weaken the shaft.  There is no useful formula for this.  It's trial and error.

If you are unable to cut the shafts I think you can add weights to the nock end to effectivly stiffen the shaft.

I know somebody has a better grasp on this than I do, so you will probably get better responses soon.

[bucksakemmer]

I have to shoot a stiff spine because of lenght so I trying to weaken the spine. Im shoot 5575 which is a 400 spine and I could shoot a 3555 but their only available in 30.5 length. I like the screw in weights so I thought I would try them.

[Jim Brennen]

I think the 3555 come in 32 inch length

[JamesKerr]

Generally ever 20-25 grains added weakens the shaft about 4-5 pounds. If you take away the 20-25 grains your arrow will be a little bit stiffer.

[Bill Sant]

Good info above, but bear in mind there are variables that a lot of people overlook, such as string material (fast flite, dacron, skinny, fat) brace height, bow cut to, past or wide of center, even the thickness of your strike plate makes a difference.  I don't use weights in the arrow as it is soooo much easier to just adjust the screw in tip weights.  Heavier if you need to soften the spine and lighter to stiffen it.