FSUBIGMAC

I put VT strings on my bow and was getting an average speed of 328 IBO at 70#. So I put on 60# limbs and am now getting 331 IBO at 60#. Anyone know why this may be. I understand that the arrows weight to poundage ratio is the same but why would I see this increase? Does the bow just function better at this weight or what? I'm certainly not complaining

TFOX

3fps,ANYTHING could cause that. Most likely just a better matched or more efficient limbs.

Were they both bottomed out and were they both getting EXACTLY 70# and 60#.

FSUBIGMAC

Both sets were bottomed out -- 71 and 61 -- same difference relatively

bowdoc1

If it's the same arrows ?Spine dose that some time. If the arrow is under spine for your weight It bend more and loose energy. The stiffer it is the less energy is lost. If you shoot over a chronograph and put a 1/2 a turn down on you limb and shoot again and repeat this you will reach a point were the arrow will start slowing down.When doing thiswith a chronograph andfinding the fasted point the arrow shoots at is what we call the sweat spot and the arrow will perform at it best there. When getting a new size of arrow tune the arrowto the bow to get the best performance out of your set up. You can do this by group tuning to by adding and taking off poundage. When the arrow working at it's bestyou will shoot your best groups.