August 25th, 2006, 07:21 PM
How many twists for new string?
I mentioned in a thread yesterday that I had picked up a TailorMade bow string for my High Country. Today, when we went to restring the bow, we noticed that the TM string was not twisted. Is there an general rule of thumb on how many twists will be necessary? The string is 97" long, and its going on a single cam High Country bow. I tried calling TailorMade, but only got their voice mail.
August 25th, 2006, 07:23 PM
If a string is completely untwisted,
Originally Posted by Jason280
for example when you are making a new string yourself,
then there are two rules of thumb
from the major string manufacturers...
1 twist per 2-inches of bowstring
1 twist per 1.5-inches of bowstring...
Rule no. 1 = 48 twists
Rule no. 2 = 64 twists.
the more twists
then the shorter the finished bow string length.
The finished bow string length
must be matched to the cable lengths.
What that means is adjust the bowstring twists
to get the draw length that fits you.
Try 48 twists.
Fire say 2-dozen arrows.
Now, measure the draw length.
Let's say the draw length is 1/4-inch longer than you want.
Keep adding twists to the bow string
to shrink the draw length.
Fire another 2-dozen arrows.
Measure the draw length again.
You will make small fine tuning adjustments
to the bow draw length by adding or taking out twists
in the bow string.
When you have the bow draw length customized
to your liking,
then take a look at the cam rotation.
Not sure about the High Country,
but I saw a thread about the Mathews Cam timing,
a single cam bow has an optimum cam rotation
for peak performance.
So, any time you adjust the bow draw length
by adding twists or removing twists to the bow string,
then you should check to see if the cam rotation needs
adjusting as well.
As you probably already know,
you adjust the cam rotation by adding or removing twists
to the cable that attaches to the peg on the cam.
Last edited by nuts&bolts; August 25th, 2006 at 07:29 PM.
August 25th, 2006, 07:25 PM
What about the cables, same rule for starters?
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August 25th, 2006, 07:36 PM
The number of twists adds stability to the finished "product"
Originally Posted by JawsDad
whether it's a bowstring or a control cable or a buss cable.
So, the 1 twist for 1.5-inch of total end loop to end loop length is a good starting point.
This gives you flexibility to untwist the bow string lengthen up to 1/4-inch
or to add twists to the bow string to shorten up to 1/4-inch since most draw length modules have a 1/2 inch adjustment range.
If you look at any "twisted rope"
you will see quite a few twists in the design because it adds stability.
You want to thoroughly wax the bow string and cables
with a quality was to allow the individual strands to slide against each other
in order to equalize tension.
When you do have 1 twist per 1.5" of total length,
then the cable or bowstring length must be accurate because at this twist rate, you really do only have a 1/4-inch range in the longer direction
and a 1/4-inch range in the shorter direction.
August 25th, 2006, 08:12 PM
Thanks for the detailed response.
I do have another questiong, though. By adding all of these twists, will I end up with too short of a bow string? The length now is 97" without any twists, and I really don't know how much shorter the string will be with the twists.
Also, how do I determine the optimal cam rotation for my bow? This bow is probably four years old, but I've only owned it for about a month or so. The original string wasn't in the best condition, which is why I decided to go ahead and change it. High Country informed me I would need a 97" string, but when I took the old string off, it was actually 98.5" long. I called HCA back, and they said it was possible the wrong string was placed on the bow from the start.
eta: I'm also going to go ahead and change the cables as well, which the local shop actually have in stock!
It does make sense, though, because the draw length never seemed to coincide with what the cam setting indicated. With the XD cam, you can adjust the draw length from 26.5-30.5". I typically shoot 27.5", but even with the cam setting on what should have been 26.5", it still seemed a little long. Guess now I know why!
Last edited by Jason280; August 25th, 2006 at 08:16 PM.
August 25th, 2006, 08:16 PM
Adjust the XD cam to the proper setting for 27.5 inches of draw length.
Originally Posted by Jason280
Now, keep adding twists to the bowstring until the bow
measures at an AMO draw length of 27.5 inches.
The cam rotation determines the percent letoff.
So, if you have a digital scale,
then you can measure the peak draw weight
and the holding weight.
Adjust the cam rotation until you get the correct holding
weight, for the peak draw weight.
August 25th, 2006, 08:23 PM
That makes sense. Do I need to worry about the overall length of the string once all the twists are added, or will it really be a non-issue?
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