should i get a heavyier spine arrow if im going to shot a heavier broadhead.  160-170gr.

sorry i never spell check.

it depends on how it flies ~!!!  does it still fly good  some times you can just add weight to the nock point of the arrow to help with stiffening up a bit

If you are perfectly tuned with 125 grain heads and want to go up to 165 grain you will probably need to either shorten the shafts about 1 inch(if you have room) or go up one 5 pound spine category... That is sort of a rough rule of thumb-if tyuou are marginally weak already you may need more if you are a tad strong but tuned that should work.

thanks for the thoughts guys i appreciate it

I have a question myself.  If you have an arrow flying good out of a bow does it matter that the spine is not "correct" for that bow.  For example, I have been shooting GT 75/95's from my recurve which was 65lbs @28 inches though I only pull about 27 inches.  Anyway, some have suggested that was overspined yet my arrows hit where I aim and fly good.  Can too much spine hurt a bow or is the only concern proper flight?   :confused:

Sorry to hijack but about spell check.
Is there one or am I just to dumb to fine it?

Bobhat,
Shoot a bareshaft at 20 yards and see how close or far off your spine is.You can probably shoot overspined arrows but any difference in your form or release could cause fliers.If you get them spined correctly you will see tighter groups.

Also a tuned arrow will penetrate much better.

Thanks RH, I'll try that and see.

Bobhat,
I guess you know but I thought I would add not to shoot a broadhead because it could go anywhere without feathers.Just use field tips the same weight.

.....and start at 10 yds and move back.