Calculating speed

[titleist_03]

I was only bowjackson trying to figure out what speed I'm shooting and I came the questiong on bow efficiency. What is it, and what is the efficiency for a 2002 Magnatec with versa cam? Also how do you figure the Stored energy/ Peak Draw Weight ratio? Thanks for the help!

[Buckfevr]

I use 1.25 and then plug #s for the efficiency until it matches up with the IBO specs, that'll get you close.

[titleist_03]

Then does anyone know the IBO of an 02 Magnatec with ZR200 limbs and versa cam?

[98Redline]

02 Hoyt MagnaTec VersaCam ZR200

BH= 8.5
ATA = 35.5
IBO = 283
Efficency = 1.1534

These numbers come out of TAP.

[titleist_03]

Hoyts website says 37 3/8. I just installed a new string on mine and measure the ATA and its 38 1/4. Is that bad? What would I do to fix it?

[PABowhntr]

titleist_03

I am going to bump this over to the tech. forum as I believe you will get more responses over there.

[titleist_03]

98Redline: Did you mean 1.1534 is the SE/PDW ratio? When I put it in for the efficiency it tells me that my speed is 33 fps.

[Buckfevr]

(Hoyts website says 37 3/8. I just installed a new string on mine and measure the ATA and its 38 1/4. Is that bad? What would I do to fix it?
[/quote]

The string or cable or both have stretched out. Probably your brace height is shorter too. First you need to check to see if the cam is in the proper position, twist up the cable or the string till it is in proper position, then check the ATA. If it is still long then shorten up both till you get the proper specs both in terms of ATA and brace.

[titleist_03]

What do u mean by the cam in proper position?

[Buckfevr]

Usually there is a position in which the cam will shoot optimally. Some cams have timing marks others use reference points on the cam relative to string alignment to indicate the proper position. Usually you can obtain the info from the manufacturers tech support. Hey did you get the IBO specs on that bow?