Bow Build Up Part 3 Initial Tuning For Draw Weight, Holding Weight, Draw Length, & Cam Lean

With our sight mounted onto the bow and leveled out I’ll move down the bow to the next accessory to add, my arrow rest.

Initially, all I will do here is just square the rest up to the riser and mount it on. I use a blade rest so I’ll check the angle of the blade at this point and get it at roughly 35 degrees. Next I will adjust the arrow rest to have the center of the blade at 3/4 of an inch, measured from the inside of the riser to the center of my blade. My last step on initial set up is to put an arrow on my string and set it on the rest for elevation adjustment. I will adjust the arrow rest to have the arrow going through the center of the berger button hole, the threaded hole the bolt goes into to mount the arrow rest, with the arrow at 90 degrees to the string. I personally use two level devices for this adjustment. I have one that I snap onto the string and one that goes onto my arrow infront of the riser a few inches. Once I find the position on the string that my arrow nock will be at 90 degrees, I will tie a D-Loop on the string. When I am finished tuning I will use tied nocking points and a loop, but for now I know that I will be moving this later on for adjustments so I only install a loop.

Now that I have a loop on the bow I will put the bow into my draw board. I will attach a scale onto the bow and the hook on my draw board, and then pull the bow back to full draw, noting my peak draw weight and what I have for holding weight. After I reach full draw I will measure my draw length and check to see how the top and bottom cams are positioned. On my Hoyt’s, when I get them new, they always have the bottom cam’s draw stop hitting the cable before the top cam. To correct this I will let the measurements I got from my draw weight determine which cable I adjust. With that being said though, I try to always use the control cable, the cable with only two end loops. The reason I do not like to use the buss cable, the cable with three end loops, is because it has a very tight bend in the cable the way it is routed on the bottom cam and I do not want to disturb the serving if I do not have to. Luckily, on my Hoyt’s I will normally come out over specified peak draw weight by 2-3 pounds. This will allow me to let twists out of the control cable to get both cams to hit at the exact same time.

My next step will be an initial setting of cam lean on my top cam and timing of the top cam, using the yokes on the buss cable. If you noticed in my previous paragraph, I noted I will adjust the control cable to have the cams touch at the same time. However, on a Hybrid set-up such as the one on my Hoyt, it will generally tune and work the best with the top cam hitting just slightly ahead of the bottom cam. So to achieve this top cam advancement, I will use the yokes and take care of two problems at once, without having to disturb the serving on the bottom of the buss cable. I will start putting twists into only the right side yoke until I can lay an arrow across the left side of the top cam and it intersect the string at my d loop. By twisting only the right side yoke this also will start shortening the buss cable and allow the top cam to be hitting first.
Once this is complete, my bow will go back into my draw board with my scale, and I will again check for peak draw weight, holding weight at full draw, and draw length. I will usually come out at or around 62 pounds of peak weight on a 50-60 pound bow, and 28.25 inches on my draw length for a 28.00 inch bow. From experience, I know that on my PCE with Spiral X cams I like to shoot somewhere in the 56 pound peak draw weight area. So to lower my peak weight out, I will start backing off the bolts holding the limbs into the limb pockets. I will do this with equal twists on both the top and bottom limbs. Each full turn will generally take off 2 pounds, so I will usually have to take out 3 full turns to get the peak draw weight to 56 pounds.

The next adjustment I will make will be two fold, and why I order a 28.00 inch Sprial X Cam instead of a 27.50 inch Cam for my exactly 28.00 inch draw length. I will once again measure my draw length and then start to put twists into my string to bring the draw length down to 28.00 inches exactly. The other affect I am getting by doing this, is raising the holding weight of my bow at full draw. Because I am shortening the string, it has a similar affect to lengthening the buss cable. It will reduce peak weight some and take a little bit of the overall rotation out of the cams to allow my holding weight to go up. The benefits to using the bow string to do this versus the buss cable is because by doing this I will not be affecting the serving in the buss cable where the most load will be and also not affecting the way my cams are timed, because I am able to move both cams at the same time.

So why do I like more holding weight than the 65% the bow has standard? Because I have spent a lot of time tweaking the holding weight until I found my best results. The higher the weight is, to a point, will allow my body to align better and help me hold steadier on target. Everyone is different though and this will have to be something you play around with to see the benefits. When I first started shooting Spiral Cams, I was coming off higher let off RKT cams and it was a much different feel. At first it was enough for me to just get used to shooting at 65%.

7 thoughts on “Bow Build Up Part 3 Initial Tuning For Draw Weight, Holding Weight, Draw Length, & Cam Lean

  1. Dennis

    Hello RC.
    This Reverend from ArcheryTalk. These blogs are excellent!! Thank you for taking the time to write them in such an understandable manner. Don’t let the goonies from AT get you down. This is great work…


    1. rchery18 Post author

      Thank you very much for the kind words! I’m really glad to see you say they’re understandable. I was trying to paint a picture with what I wrote.

  2. Kris

    You did not explain how do you mount your blade rest. I believe you have to keep the arrow at 90 degrees to the string and then raise the rest till the blade just “kisses” the arrow shaft and when you let the arrow loose on the blade it should sag and will not be 90 degrees no more to the string (at rest) but when you pull the bow to full draw it will straighten.
    Correct me if I’m wrong.
    Good job by the way. Love the write up. But I’m the kind of person that like some photos too 🙂
    Keep it up

    1. rchery18 Post author

      I’ve seen Nuts&Bolts set his rest that way and I’ve tried it as well. That’s a good method. When I used it I ended up bringing my rest up some to get my bare shafts to hit the way I wanted that I’ve found will group tune better at distance. When I set the rest to give me 90 degrees or just slightly under 90 with the arrow weighting the blade I’ll move the rest down slightly to get my impacts the way I like. It’s easier for me to set it at or just below 90, which is why I’ve stuck to that. But either will give great starting points and results depending on the bow.


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