I just bought a new bow in sept. but once it was set up and ready i SPEED checked it and for a bow that is IBO'd at 340-350 the best I could get was 268 or 286 now for 70=lbs and a 30 1/2 arrow it should be well over that...any ideas? I have been told it could be cam timing but im not sure....HELP

Too little info to make a good guess but it also depends on what your draw length is how much your your arrows weigh. Unless you are shooting a 350 grain arrow and your draw length is 30 inches you wont get the rated speed. Plus SOME manufacturers exaggerate the IBO ratings for their bows.

Sounds like a ______! Overrated speeds sells bows, even those that know that they are rating the bows to high will still buy them and complain. If you just bought the bow I wouldn't think the bow is out of time, but how heavy is your arrow? If the bow is right with a the dl and dw you have you should get at least 300fps.

What's your draw lenght?, and do you know what your arrows weight?

For every 1" of draw lenght equals 10fps, i.e. your 28" you lost 20fps from ibo spec.

For every 3grs of arrow weight equals 1fps.

1 lbs draw lenght eqauls 1.8fps

If your cams were out of time it would affect your group size.

The manufacturers also measure the IBO speeds without anything on the string.

Adding nocks, D-loops, peeps, silencers, etc will also reduce the speed a little.

The only manufacturer that I've seen that advertises honest IBO speeds is Hoyt. Others may, but I haven't seen them.

Allen