How do you determine what vane length to use? I' m going to be trying some acc 3-49 and beman ics 400' s and wondering what u would recommend.

yes you can be too long depending on your arrow rest (release shooters in general).

generally most people use 4" with carbons in a straight offset with a launcher or prong style rest. If you shoot a fall away you can shoot 4" or 5" with helical, heck you can even shoot 4 fletch if you want. This is for mechanical or fixed blade heads.

for mechanical heads some people use nothing but straight fletch and you will find anything from 3" to 5" fletch being used with them with the vast majority using 3" or 4" .

With fatter diameter shafts such as aluminum 2315' s or 2512' s as examples you will mostly see 5" offset straight or helical. since the shaft is fatter you have more room to get better fletching clearance out of most styles of arrow rests. you do see a fair share of 4" on aluminum anymore.

Hope this helps you out some.

I' m not really sure but can' t it throw of your FOC with the weight of the vanes on the back of the arrow?? the longer vane=more weight??

Longer Fletching will have very little effect of the arrows FOC% unless you are too light up front to begin with.

you want enough fletch to keep your arrow stable in flight but not so mutch that it will cause so mutch drag that it slows down the arrow.

If you are using field points or mechanical heads you can get away with using short fletch arrows.

But with broadheads you basically have the same thing on the front as on the back of the arrow the problem with being up front is that the Broadhead will steer the arrow instead of creating drag. this is where a 4" to 5" fletch works better than short fletch.