New Article: The Truth in Bow Speed

[robby denning]

Check out a great read by Rokslide Prostaffer, Evan Williams. This guy works full time in an archery pro-shop (Bill Pellegrino's Archery Hut, Colorado Springs) and spends more time in a week working with bows than most of us spend in a year. He shows us the truth in ATA vs IBO when rating a bow's actual speed. Check it out.
http://www.rokslide.com/2012-01-09-05-09-42/archery/292-the-truth-in-bow-speed-ata-vs-ibo

 

[Manosteel]

Good article, short, sweet and to the point.
A good explanation for many who end up being disappointed that their 340 FPS bow only chronographs a real world 280 fps.

 

[robby denning]

Good article, short, sweet and to the point.
A good explanation for many who end up being disappointed that their 340 FPS bow only chronographs a real world 280 fps.

I hear a lot of those guys complaining!

 

[5MilesBack]

Sorry Evan, that just made it more confusing to me. For years I have understood IBO to be 70lbs, 30" draw, and an arrow at 5gpp. You're saying that someone can throw numbers out there as an official IBO speed at 33" draw?

Now I know PSE rates their bows at all sorts of different draw lengths. For instance the 2014 Freak SP shows a speed as IBO 354fps at 33" draw and 70lbs. When I see this I just subtract 30fps and say it's a 324IBO bow which is what it should equate to at 30" draw. That 354 number means absolutely nothing to me except to give me a starting point to get back to what I consider an official IBO speed of 324fps. As long as I know they're using 33" in their numbers, I'm OK with that........I can do the math.

Then I laugh when I shoot a bow with an advertised IBO of 335, and it's 13fps SLOWER than my 316 IBO bow that I've been shooting for the past 8 years. Not even sure how that happens.

BTW, I shoot at 32 1/2" draw, for those that don't already know that.

 

[Slim Jim]

Good article Evan. Honestly I never even pay attention to the speed specs of new bows. I shoot 60# with a 28.5 draw so my numbers are always way below. My Hoyt Faktor 30 with a 412 grain arrow shoots 272fps and I it lists 332fps. BIG difference

 

[Evan Williams]

5MilesBack

I'm saying JUST that! For YEARS people have thrown all those "SPECS" on IBO speeds as "THE STANDARD" and it isn't correct. You can go right to the IBO website and see that it's spelled out plainly.

And since you brought up PSE by name. That's how they can post those numbers and still list IBO because there ARENT draw length standards because IBO was created for 3Ds and they know no 2 people are the same it's how they can run their tournaments.

An ATA spec speed is going to be MUCH more consistent.

The other thing to bring attention to is the fact that you WILL NOT lose 10 fps per draw length so you can't see a 360 at 33" and assume at 30" it's 330. Won't happen because of change in cam position depending on how the manufacture utilizes draw length ETC I start at -12 fps per inch and the shorter it goes down the more I subtract per inch. Just something else I've learned.

 

[Craig Van Arsdale]

Good read Evan. Thanks didn't know IBO numbers were so loose.

 

[Manosteel]

I have know this for a while, which is part of the reason I ended buying my own chronograph years ago. It got to be too much of a headache trying to figure out bow speed and KE / ME numbers using manufactures specs. I found my Mathews bows were the worst offenders... they were still fast but not 344fps fast and I have a true 29-3/4" draw length and I have always shot around 70lbs give or take a few, so it should be pretty straight forward for me and it never was.

 

[Nick Muche]

Nice article. I've never understood the allure behind FPS, I just shoot and it goes as fast as it can

 

[Evan Williams]

Nick ;-) yeah I chrono for 2 reasons.

1: building my sight tapes with archers advantage

2: running my KE which....still is only gonna be what it's gonna be ;-)