Bow Performance

[gabenzeke]

I'm looking at getting a new bow. One thing I am considering is jumping up to an 80 pound draw weight. My question is, if I end up settling somewhere in the middle, say 75 pounds, what would I be losing in perfomance? I know I could just shoot 70 pounds, so I'm not looking to be convinced to just shoot 70. I'm just looking for info regarding performance if a bow is set at a weight less than the maximum.

 

[Rick Leathley]

I have read that limbs are most efficient set to max.

That said you'll still get speed power increase shooting 80# limbs set to 75 over maxed 70#

 

[charvey9]

Exact difference would depend on the bow, dl, arrow, etc, but i'd ballpark it at roughly 5-8fps.

You can play with different settings here to get an idea:
http://archerycalculator.com/estimate-bow-speed/

This assumes you'll be able to shoot the same arrow at each poundage. The higher draw weight may require stiffer spine depending on your exact setup.

 

[gabenzeke]

So aside from speed, are there really many drawbacks to not shooting a maxed bow? I've heard there could be a slight difference in how quiet the bow is, but is that pretty much it?

 

[roadrunner]

I once had a 70# bow set at 65# and it shot great with no issues, noise, etc. Something to think about, a bow maxed out will be anywhere from 2-3 lbs higher in draw weight than what it "says". So, if you were to get a 70# bow and max it out, you'd be in the 73# range, only 2 lbs less than what you're seeking and also getting into the proverbial "max efficiency" of the bow.

 

[MattB]

Draw length typically increases when shot without the limbs buried as well.

 

[Matt W.]

Check out a 70lb Xpedition X7... Specs on that are pretty darn good.

 

[5MilesBack]

You'd have to set up two of the same bows set up, one a 80lb'er set at 70 and a 70lb'er set at 70 and shoot them to see what the performance differences were. However, I don't think it really would matter too much. I've shot my bows at all kinds of different draw weight settings and it's not enough to worry about. For 3D sometimes I set the bow up with a particular set of arrows and then drop the draw weight until the speed of the arrow is exactly what the allowable maximum is.

 

[charvey9]

All performance stats will be influnced by changes in draw weight. If shooting the same arrow, reducing draw weight will also decrease speed, KE, momentum, etc. Whether or not those differences are significant is up to you.

However it does not sound like you are asking about numbers, but want to know if there are problems associated with setting up a bow below the max rating of its limbs (regardless of the actual draw weight). The answer to that, as far as I know, is no. In fact the limbs are often backed off a bit when tuning to get proper timing and flight. You should not experience any problems setting up a bow anywhere in its allowable range of draw weight, and tuning accordingly.

 

[gabenzeke]

Thanks everybody. Shot an elite impulse yesterday at 70 pounds. The thing is so much smoother than my current rig I think I've decided on 80 pound limbs and I doubt I'll have trouble shooting it maxed out.