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Main Boards => PowWow => Topic started by: Rustic on October 12, 2011, 11:19:00 AM

Title: How do you calculate draw weight??
Post by: Rustic on October 12, 2011, 11:19:00 AM
Just getting into trad bowhunting. From what I've seen, a bows draw weight is based on a 28" draw length. Longer pull = higher draw weight.
Therefore, what does a 26" pull equal?? Thanks in advance.
Title: Re: How do you calculate draw weight??
Post by: cedar on October 12, 2011, 11:28:00 AM
Add or subtract 3 lbs for every inch over or under 28.  This will get you close.
Title: Re: How do you calculate draw weight??
Post by: on October 12, 2011, 11:28:00 AM
Depending on the bow, you can add or subtract about 2-3 pounds for each inch of draw length. The best way to find out for sure would be to put the bow on a scale and pull it to 26".

Bisch
Title: Re: How do you calculate draw weight??
Post by: wtpops on October 12, 2011, 11:31:00 AM
As a general rule a bow will gain or lose 2.5 to 3 pounds per inch within its power curve. If you draw t0o far out of that curve the bow will start to "stack" (increase dramatically in draw weight)

So if you have a bow 50# @ 28 and draw 29" it will be approximately 53#, if drawn to 27 it will be approximately 47#
Title: Re: How do you calculate draw weight??
Post by: Jeff Strubberg on October 12, 2011, 11:41:00 AM
You really need to measure draw weight.  There are lots of general rules, but bows are individual critters.

Custom bows are typically weighed and marked for the draw length they were ordered at.  Production bows are typically marked at 28 inches of draw.
Title: Re: How do you calculate draw weight??
Post by: huntmaster80 on October 12, 2011, 11:46:00 AM
most of them will give you about a 2-3# difference per inch. but measuring it is the only way to go, cause every bow is gona be a bit different
Title: Re: How do you calculate draw weight??
Post by: on October 12, 2011, 12:04:00 PM
OK--here's another question--when weighing draw weight on a scale, do you deduct the physical weight of the bow (tare)?? When I do this, my bows typically weight in a pound or 2 less than marked. What do bowyers do?
Title: Re: How do you calculate draw weight??
Post by: Night Wing on October 12, 2011, 12:09:00 PM
Quote
Originally posted by Bisch:
Depending on the bow, you can add or subtract about 2-3 pounds for each inch of draw length. The best way to find out for sure would be to put the bow on a scale and pull it to 26".

Bisch
This is how I measure mine.
Title: Re: How do you calculate draw weight??
Post by: Bjorn on October 12, 2011, 12:10:00 PM
That is a good question as almost all bowyers do the subtraction but some do not.  Jack Howard bows are always over the marked pounds, they have very heavy risers and Jack did not subtract.
Title: Re: How do you calculate draw weight??
Post by: Jeff Strubberg on October 12, 2011, 12:49:00 PM
Depends.  My scale setup has the bow sitting in a cradle at the handle, then pulling down against the string with the scale.  Bow weight is irrelevant here.

If you are hanging the bow from a scale and pulling on the handle, then you would need to subtract bow physical weight.

This will make absolutely no difference to your 28 to 26 inch comparison though, as bow physical weight will remain the same in both cases.
Title: Re: How do you calculate draw weight??
Post by: Yellow Dog on October 12, 2011, 01:23:00 PM
I draw 30'' and I use an arrow with insert installed and no point that's exactly 30''. Put my trusty old Bear hand scale on the string and pull it until the end of the arrow is flush with the front of the riser. That weight is my weight @ 30. I also have one at 28'' to verify draw weight @ 28. As others have said 2 to 3 pounds per inch depending on the bow.
Title: Re: How do you calculate draw weight??
Post by: Flying Dutchman on October 12, 2011, 02:30:00 PM
You have to add or substract 5% of the 28 inch drawlenght per inch. Not just 2 or 3 lbs.
So if you are shooting a bow of 50lbs@28" and you draw 29", your drawweight will become 52,5. Deadeasy!