draw length vs draw weight

[guk]

I know all bows are a story unto them selfs. But has anyone found a number. Is 50@30 the same as 55@28? Did a search nothing came up.

[BOHO]

it used to be generally every inch was about 3#'s. I think some bow's are 2#'s but not many.

[TSchirm]

Closer the other way around.  Most bows gain 2 - 3 lbs per inch of draw, so in this case it would more likely be 50 lbs @28" and then 55 lbs @30".

[Prairie Drifter]

Guys, I think he's comparing preformance/arrow speed, not draw weight increases.

[drewsbow]

I not sure you can really compare it that way but for my money I'll take long draw with a lower starting weight every time. I shoot 42@28 but draw long so I get close to 50 out of it and feel I get more for my money that way.  Drew

[**DONOTDELETE**]

i don't have any specific numbers to reference for you, but yes... a longer draw = a longer power stroke and will provide higher performance at less draw weight.

for example. the 50@30" draw will typically have higher performance than a 50@28" on identical limbs shooting the same arrows.

There are exceptions to the rule though when the limbs are built for a specific draw length.

[Ragnarok Forge]

My google fu must be strong tonight.  I just did a search and found several links to sites that referenced an AMO 9 gpp arrow drawn to 28 inches will be 4 to 5 fps slower than the same arrow on the same bow drawn to 29 inches.  This would mean that an extra two inches of draw should give you 8 to 10 fps more.

[joevan125]

A well known bowyer who draws around 27in told me that with my 30in draw he wouls have to shoot at least 15 more pounds to get the same speed from his bows.

Joe Van

[Night Wing]

If you're going to go for foot pounds of energy and arrow speed, some of you might find this interesting. Keep in mind my 42# recurve likes a stiff arrow and I'm shooting a 62", 12 strand Dyna97 fast flight bowstring.

With my 30" draw length and shooting my present 32", 421 grain 2212 aluminum arrow with a point weight of 75 grains out of my 66", 42# @ 30" recurve, it generates 32.1 foot pounds of energy with an arrow speed of 185 fps.

If I had a 28" draw length and shot a 66", 45# @ 28" recurve, I could shoot a 30", 433 grain 2212 aluminum arrow with a point weight of 105 grains giving 34.4 foot pounds of energy with an arrow speed of 189 fps.

In closing, the 45# @ 28" recurve gives better results than the 42# @ 30" recurve in both foot pounds of energy and in arrow speed.

Just food for thought.

[Bowwild]

Interesting discussion.  

However, since we are all stuck with a very specific correct draw length based upon our physique, we have to consider other variables.

My draw length is 26". At my age and level of conditioning (too old and not enough) I'm comfortable with recurves that draw 46-49# @ 26".  

This means most of my bows are 51-55@@28. I check every bow I own or test-drive to see what the actual draw weight is at 28" and 26". Some are right on and others could be off 1-6 pounds.

I admit this is a very limited range of measurement.  Shoot, I can barely get an arrow drawn 28" even to measure it before I run out of arm.

I find that most of my bows are almost exactly 6 pounds lighter (3#/inch)when draw to 26" rather than 28".

[**DONOTDELETE**]

Originally posted by Night Wing:
If you're going to go for foot pounds of energy and arrow speed, some of you might find this interesting. Keep in mind my 42# recurve likes a stiff arrow and I'm shooting a 62", 12 strand Dyna97 fast flight bowstring.

With my 30" draw length and shooting my present 32", 421 grain 2212 aluminum arrow with a point weight of 75 grains out of my 66", 42# @ 30" recurve, it generates 32.1 foot pounds of energy with an arrow speed of 185 fps.

If I had a 28" draw length and shot a 66", 45# @ 28" recurve, I could shoot a 30", 433 grain 2212 aluminum arrow with a point weight of 105 grains giving 34.4 foot pounds of energy with an arrow speed of 189 fps.

In closing, the 45# @ 28" recurve gives better results than the 42# @ 30" recurve in both foot pounds of energy and in arrow speed.

Just food for thought.

The reason you have a higher performance on the shorter draw, higher poundage bow is that your PPI is only 9.62 gpp and the lighter weight bow is coming in at 10.02 gpp.

there are exceptions to the longer draw = higher performance theory. The geometry of the limbs and how much energy they are storing through the draw cycle, and the amount of preload at brace can alter the results.

If you do the same tests with a 52 pound bow and a 55 pound in the same design using the same gpp arrows you will get different result too.