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Discussion Starter · #1 ·
Hey guys/gals,

I've had my OB Evolution for about 2 months now and put a few hundred shots through it, great bow. Now that I feel that I have broke in the strings I have decided to check all the measurements, timing, etc. and all except the ATA seem to be within spec. I know that this is a rough number only, but here are the measurements that I have right now:

BH: 6"
Maxxed DW: 70.2# (bow is 60-70#)
DL: 28.5"
ATA: 32 7/16"
FPS: ~310 w/ 378gr arrow and peep, loop, and speed nocks on strings

Is this extra 7/16" anything to actually worry about in this case? The bow is shooting just fine (getting 5" groups at 60 & 70 yards and broke several arrows at 20-40yards) so I don't feel that I NEED to change anything, but would like to know if there is any real benefit to bringing the ATA closer to spec. Not looking for any additional speed really, but if it comes with a slight tweak then I'll take it!

Thanks in advance.
 

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Hey guys/gals,

I've had my OB Evolution for about 2 months now and put a few hundred shots through it, great bow. Now that I feel that I have broke in the strings I have decided to check all the measurements, timing, etc. and all except the ATA seem to be within spec. I know that this is a rough number only, but here are the measurements that I have right now:

BH: 6"
Maxxed DW: 70.2# (bow is 60-70#)
DL: 28.5"
ATA: 32 7/16"
FPS: ~310 w/ 378gr arrow and peep, loop, and speed nocks on strings

Is this extra 7/16" anything to actually worry about in this case? The bow is shooting just fine (getting 5" groups at 60 & 70 yards and broke several arrows at 20-40yards) so I don't feel that I NEED to change anything, but would like to know if there is any real benefit to bringing the ATA closer to spec. Not looking for any additional speed really, but if it comes with a slight tweak then I'll take it!

Thanks in advance.
ATA, axle to axle length is a GUESS by the manufacturer
how much you need to BEND the limbs
to get 70 lbs of draw weight.

Your two limbs are the same as a leaf spring suspension on a heavy duty truck.

BEND the limbs TOO MUCH?
Draw weight goes OVER 70 lbs.

BEND the limbs NOT enough?
Draw weight goes UNDER 70 lbs.

MAKE the limbs too THICK?
ATA must GROW to hit 70 lbs of draw weight.

MAKE the limbs too THIN?
ATA must shrink to hit 70 lbs of draw weight.

IF you are happy with the draw weight,
then,
IGNORE ATA.

If you blindly twist cables SHORTER and SHORTER
to "hit" spec, for ATA,
then,
your draw weight will go OVER 70 lbs.

Then,
your next post will be
my bow makes 76 lbs of draw weight,
but,
my ATA is to spec?

WHAT now?

Answer...make ATA longer, until you hit 70 lbs of draw weight.
 

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Discussion Starter · #3 ·
Awesome! I will leave the bow as-is then. Thanks for the help. I knew that ATA was a rough guestimate but wasn't sure if 1/2 in was acceptable. Thanks again.
 

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I'd think 1/2" is a little much but in reality, if it tunes easily, shoots well and has the feel you're looking for...you're there.

Tune it, shoot it- smile and have fun
 

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Something that I wasn't aware of until I started messing with Obsessions Evo/Phoenix and confirmed it with Breathn is that as that as the draw length gets longer the ATA gets shorter...With that said my Phoenix is 32.625 ATA but the draw length and poundage is spot on...That's all I'm concerned with unless it becomes a tuning issue...

So I would say that your ok with what you have so long as the draw length and poundage is good

Moral of the story, ATA and Brace are approximates and depending on the company, the same rules don't apply...Find someone who has experience with that particular company or you will drive your self batty trying to get everything spot on...
 

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Most of my finished builds/tunes end up around 1/8" to 1/4" long on ATA (32 1/8 32 1/4"). That said, I have had some in the range that you are describing as well. Draw weight and length need to be set to spec and then ATA is a by product. Once the BH, Draw length and poundage are all in "spec" the bows tune up great and stay there...just my experience, others may vary (enter typical AT disclaimer here). I think it sounds like your rig is in great shape. Have fun knocking the stuffing out of whatever you point it at.
 
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