What's the difference in IBO speed going to be with 80# limbs vs 70# limbs?

More than 5 fps

less than 10 fps

give or take 5 fps

LMAO @ Rack.

What he is saying is there will be no difference in speed. 5 grains per pound is 5 grains per pound regardless of the draw weight. I'd be suprised if you see any difference. At 70 pounds an "IBO legal" arrow would weigh 350 grains, at 80# it would be 400 grains.

The IBO speed with 70# limbs is 310-fps.
The IBO speed with 80# limbs is ???

You would probably see a slight increase in speed with the 80 lbs limbs and a 400 grain arrow....but I wouldn't feel comfortable being the one to test any bow at those specs. I leave that up to Vic.....

I would guess about 3-5 fps faster.

I actually have shot an 80# Razor through a chrony with a 400 grain arrow, bare string at 30 inches and I got 312 fps. Like was said, by going up in draw weight you also have to go up in arrow weight to keep the 5gr/#, so there is very little difference all things considered.