Difference in speed between 60 lbs and 70 lbs?

[bobcat]

What's the difference in speed out of a 60 pound bow versus a 70 pound bow, everything else being equal? I'm looking at a couple of bows on eBay and can't decide if I should bid on the 45-60 lb or the 55-70 pound bow. In the past I hunted with a 70 pound bow, with 65% let off, and had no problem pulling it back. But it did cause me shoulder problems occasionally when I would shoot excessively at one time (and that was one of the reasons I quit bow hunting).

I think it might be better if I limited myself to 60 pounds, but I'm worried about the loss of arrow speed. Especially with my draw length being short (about 26 1/2).

So is there that much difference between 60 and 70 pounds, as far as arrow speed goes? I know I could just get the 55-70 and I'd be pretty well covered, since I could start out at 60 and bump it up some if/when my muscles got used to it and allowed me to pull back more weight.

But I'm wondering if there are more people bidding on the 70 pound bow, and I could get the 60 for a lot less money, I might be just as well off with it.

[300UltraMagShooter]

no set way to know without just testing...

most bows your looking at about 2.5 to 3.0 fps/lb if memory serves me...

so roughly 25 to 30 fps

[daddysprad]

Try this calculator.  Not an exact science, but will give you some ideas. 

http://www.backcountrybowhunting.com/articles/calc/

[300UltraMagShooter]

one other thing, maxed out bows are generally more efficent than ones backed off some.

so a 45-60 lb bow set on 60 lbs will generally be more efficent than a 55-70 lb bow set on 60 lbs....

when you back off on weight, you can back off on arrow weight to get your speed back up, however, you'll not really gain that much in arrow arch because a light arrow slows down faster than a heavy one unless you improve dynamics of the arrow....  (same as bullets)

[bobcat]

no set way to know without just testing...

most bows your looking at about 2.5 to 3.0 fps/lb if memory serves me...

so roughly 25 to 30 fps

Thanks. That's all I wanted was a rough idea.

So the deal is I just got permission to hunt some property near where I live, with the stipulation that I can only hunt with a bow. So if I even do hunt the property I may just do it with a modern tag and it may only be a couple of days total. For that reason I'm not wanting to spend a lot of money and that's why I'm looking on ebay for something cheap.

If I got the 70 lb bow I'd probably hunt with it at no more than 65 lbs. If I got the 60 lb bow I'd hunt with it at 60 lbs. So that's 5 pounds difference and from what you're saying that would be a 15 fps difference at the most (since these are identical bows)

So then the question becomes, is 15 fps significant? I would likely be hunting from a stand so the range would be known, and from my past bow hunting experience, I know I would limit myself to a maximum of 40 yards.

I'm thinking the 15 fps won't matter much given this scenario?

[bobcat]

one other thing, maxed out bows are generally more efficent than ones backed off some.

so a 45-60 lb bow set on 60 lbs will generally be more efficent than a 55-70 lb bow set on 60 lbs....

when you back off on weight, you can back off on arrow weight to get your speed back up, however, you'll not really gain that much in arrow arch because a light arrow slows down faster than a heavy one unless you improve dynamics of the arrow....  (same as bullets)

What is the advantage of "efficiency"?

[bullcanyon]

Its usually 20 fps difference from a 60 to 70 lb bow. I've always shot my bows backed down a couple turns. No issue. Can't say what exactly im missing out on but its said that I am? As long as it feels good and slings broadheads. I don't care.

[Button Nubbs]

I notice a decrease in accuracy when I back my bow down from 70lbs to 65lbs. What are you hunting deer, elk, turkey?

[bobcat]

I will only be hunting deer with it. Of course the opportunity for a bear could also come up in the area I'm hunting. Elk could be a possibility in the future, especially if I decide to spend the money on the multi-season permit. But for now I'm doing muzzleloader for elk.

[bobcat]

Maxed out is more accurate is what I have always been told. I recently bought a new bow and went with a 60# since I previously had a shoulder injury. I backed it down to 52 and started shooting. Working my way back up to 60. It is comfortable and I am not having the shoulder problems. Glad I went with the 60.

I've never had my shoulder problem diagnosed by a doctor but I know there's some sort of problem with it. I've injured it a few different times and it takes up to 3 or 4 months to heal when that happens. Which is a good reason for me to stay with a bow that is easy to pull back. I don't think 60 lbs would cause me any problems.

[Tony]

I'm not an expert by no means but i shot a Mathews with the weight backed down to from 70lbs to 60lbs and a similar draw length as you and i am shooting 302fps. Just my   the difference in speed really wouldn't be a factor its going to come down to the shot placement.

[spookgus]

60 lbs is fine for deer, bear and elk. If comparing similar bows and using 6 grains of arrow weight per lb(60lbs 360gr, 70lbs 420gr), I think the velocity difference will be negligible. The 55/75 Gold Tip with feathers and 100gr tip should be close to 360gr. I know a heavier arrow has more kinetic energy, but I shot a 380 grain arrow through an elk that had enough energy left to stick into a clay bank behind it. Granted this was at 75lbs(not in Washington).

[DBZona]

In my opinion,  the faster the bow...the faster the miss. 

I would shoot what your comfortable with.  You will be far more accurate with a comfortable weight that you can comfortably practice at than at a weight you can only shoot a few times before it starts bothering your shoulder.  There are far more important things than speed when figuring out your setup.

[300UltraMagShooter]

I'm just going on what i've been told by several shops on the efficiency thing.

They said it has to do with the design specs of the bow and the more energy transfer into the arrow.

I'd think that a significant loss of energy could come from where the limbs connect to the riser.  When you have it tightened down, the limbs and riser then become more or less one piece which should make it more efficient.  Just guessing here.

Bows are very simple and yet complicated...  no matter what they do to them, you only get the speed out of it through what engergy you put into drawing it back.  (barring design improvements that make sure as much energy as possible goes into the arrow.)

60 or 70 lbs is not gonna make a bunch of difference unless you are maybe a one pin shooter and want to set one pin out to X yardage.

You can get bows that are 60 lbs and they will shoot with a 70 lb bow...  however, you are going to be pulling that other energy back somewhere in the draw cycle.  Usually these bows are not the smoothest to draw back, if that bothers you.  Me personally, I like a smooth bow and just pull more weight "if" i want more speed.

Another loss of energy is in the bow limbs.  When you bend a limb, it takes more energy to bend it than is actually stored in the limb while it is bent.  The newer bows with the supports in the middle of the limb help balance that out some...

Another area of course is brace height.  You can get some of that energy back by shooting a shorter brace height.  No free lunch, you are giving up one thing to get another.

All breaks down to personal preference and how you want to shoot your bow at your desired speed.

[spookgus]

If I were you and you were my age, I would go 60lb bow and not look back. 60lbs is more FUN to shoot. More FUN to shoot means more shooting. More shooting means more accuracy. More accuracy means more deadly. More deadly means more success. More success means more FUN. I went through a couple decades with 90+ lb bows and 5lb magnum rifles but now I have more FUN with my old 30-06 and 60 lb bows. Just like women, now I have more FUN with a Lincoln than a Ferrari.