PDA

View Full Version : Draw length and cable/string twisting



hunt123
10-22-2010, 11:01 AM
Could someone spell out for me what twisting/untwisting the cable and string does?

Like:
Twisting the cable 1/2" shorter = ??
Twisting the cable and string 1/2" shorter = ??
Twisting the string 1/2" shorter = ??

Or something like that.

I've read different posts until I'm nearly brain fogged and still can't get it. Basically I want to take 1/4" out of my DL without changing my loop but I'm also trying to learn the principle behind it.

Hutch~n~Son Archery
10-22-2010, 11:13 AM
Twisting the cable loads more pounds on the limbs and adds draw length.
Also shortens ata.
Twisting the string shortens the draw length.
Also changes cam rotation.
Hope this helps
Hutch

SonnyThomas
10-22-2010, 11:44 AM
I'll take a stab at this. I assume by cable and string you have single cam.

In order for this to work the buss cable must be capable of being untwisted by at least 4 full twists and yet maintain integrity, resemblance of. Just a 1/4" shouldn't take much.

To shorten draw length you have to over rotate the cam and yetmaintain brace height or less. This would be twisting the bow string and untwisting the buss cable. By a major string maker the ratio is 4 to 1. Twist the bow string 4 times and untwist the buss cable 1 time. NOW, all bow strings are not equal in length. So have the bow in optimum time/cam rotation and very close to ata (where ever max. poundage is achieved). Brace height should approximately correct. Write down both and begin.

hunt123
10-22-2010, 12:20 PM
Yes, single cam.

So if you twist the string 4 times, you untwist the cable 1 time and that keeps the cam rotation as it was before? And you've shortened your DL without messing anything else up?

If I take 1/2" out by moving to the other cam pin and want to put a little back in, then I: Untwist the string 4 times and twist the cable 1 time? Just the reverse of the first scenario?

It's shooting real nice now and I'd like to keep it that way, just want to see if a shorter DL feels better.

SonnyThomas
10-22-2010, 03:50 PM
[QUOTE=hunt123;33338]Yes, single cam.

So if you twist the string 4 times, you untwist the cable 1 time and that keeps the cam rotation as it was before?

No. In order to shorten draw length you are over rotating the cam. Okay, you're rotating the cam to the draw stop quicker.

And you've shortened your DL without messing anything else up?

Yes, basically. I once put together a Frankenstein bow (Bow Logic with Pearson Z7 cam system) and twisted/untwisted the strings to shorten draw length by 2 inches. Okay, don't do this. Here, I didn't care if I tied the string in knots as I was wanting to get the correct length to order custom strings.
QUOTE]

Here's a pic. Left is cam at 29" and right is at 28 1/2". You can see the scribe lines in the cam face.

hunt123
10-22-2010, 04:17 PM
Well, before I confuse myself again I'll just go with the +4 -1 method for shortening and the -4 +1 method for lengthening.

My cable's about to break and I've sent off for another so I won't be able to try for a few days.

Another question: I put this new cable on, and maybe I have to twist it up a little to get my ATA right. Does that mean I have to do something to my string also?

FireHawk Owner
10-22-2010, 04:36 PM
Do you have a modules on your cams. If you do, that would be an easier way to change your draw length and not have to worry about over rotating your cams. Just a suggestion.;)

Hutch~n~Son Archery
10-22-2010, 04:47 PM
Do you have a modules on your cams. If you do, that would be an easier way to change your draw length and not have to worry about over rotating your cams. Just a suggestion.;)

I agree 100%

hunt123
10-23-2010, 10:53 AM
Do you have a modules on your cams. If you do, that would be an easier way to change your draw length and not have to worry about over rotating your cams. Just a suggestion.;)

I have all of them but they each change the DL by 1". I only want to change it by 1/4" at a time. I'm real close now, maybe all I need is 1/4" less. If I need 1/2" I'll switch pins on the cam.