OK. I've been meaning to write this for a while now but haven't found the time. This is kind of an information dump on what I've learned about the bow so far and how/why I've been tuning it. This thread isn't a review other than to say that I love mine and have had zero issues with it so far.
Since I got the bow three weeks ago I have installed two different sets of strings and cables on it (my own) and have tuned it from scratch three different times so I am speaking form more experience in tuning this bow than most. The first two pictures are of the bow in its current iteration. The strings I've made for it are black/flame with clear roller guard servings. I like the looks a tad better than the stockers but opinions...opinions. The strings are 20 strands of 452-x and the cables are 24. Everything is served with .014 Halo. I would like to point out how well the factory strings are made with one exception. Usually I can make a good pre-stretched set and see some immediate speed gains but that was simply not the case here. I made two different sets and played around with speed nocks for hours at a time (probably five or six all told) and could not find more than one or maybe two fps over the stock rigging. This speaks of how good the stock strings are. I did dislike one thing however. While I was tuning with the stock strings I did notice a need to "shoot in" the cables several times after each adjustment. Even then when I'd leave the bow for extended periods there was some movement as things settled over night. I believe that the "y" not being served on the cables was the culprit. When it isn't served the cable has two settle in two areas with each adjustment...it has to equalize at the legs then that pressure has two equalize within the entire strand bundle itself. Both the sets I made are served at the "y" and I didn't notice this tendency at all with mine. I simply made adjustments shot twice to settle and they stayed put. Therefore, if you like to tune your own equipment and tinker with your bows I believe you are better off with either a served "y" or a floating yoke. People that are keeping the stock strings may want to get the "y" served on the stock rigging. Also, while on the topic, I'd like to note how very sensitive this bow is to string weight. This is something to consider for hunters in particular. With the stock strings I put cat whisker silencers on the ends of each serving and in the normal mass. The bow dropped 8 to 10 fps!! I was able to get that drop significantly less by reducing the number of speed nocks to one per side and placing the silencers on the ends of the servings. This netted a 4fps loss but did help quiet the bow. The point is if you are going to put silencers on the string without compensating for the added weight expect dramatic speed losses. I've never personally seen a bow this sensitive to string weight. In the pictures you ca see that I came to the same conclusion Bowtech did...leave the silencers off the string or you'll suffer some speed loss.
Now to tuning. Probably the single most important observation I can pass on to my fellow AT'rs is how very dramatic small adjustments make on this bow. As far as the split yokes go 1/2 turn adjustments at a time make a huge impact on tuning results so be carefull and always keep the big picture (ATA and specs) in mind while twisting. I would also like to note that I m a perfectionist when it comes to tuning and I see no reason why any of these bows shouldn't tune dead down center if you know how to yoke tune. I always tune my bows so that all three major tuning methods (paper, walk back, braodhead) complement one another. If I have to compromise one tuning method to get another in then I usually know my arrow spine is off which brings me to setup.
Im using GT .340 spine arrows cut short (26.5") with a 100 grain tip. This arrow is approximately 381 grains. The bow is set at 67lbs with a 28" draw. I did chrono this setup with an IBO weight arrow at around (average) 328fps with a loaded string (mine) which puts it about 1 or 2 fps faster than the IBO rating.
The first picture that relates to tuning shows what I believe is the best starting point for pre-angle for the split yoke/cam combo. This picture shows an arrow held flat against the upper cam like most tuners do for Mathew's idler lean placement. I start by placing the arrow rest exactly at center shot then work the cam angles into that position. I've found that the top cam needs to start top left so that the arrow held against it's left side meets the string just below my peep sight ( about 6.25" above center of nocking point). I hope you all can see what I'm getting at in the picture. Once this is set and I have both cams set at the same angle and my ATA and other specs are in as well including a good initial timing and synchronizing of the cams I begin with bare shafts through paper at about 5 yards. The reason I do this is because it shows very clear and immediate results for each change you make. Shoot and see what's happening and take care of the easy nock high or low adjusment first. With my setup a tail right tear was lessened by a half twist in each right yoke. The key is to use only 1/2 twists at a time and you'll be amazed at how much of a difference these small adjustments make and you'll see if the tear is getting smaller or larger then move again. If your trying to keep your timing exact once you see where you have to go with your static cam angle you can twist 1/2 in one side then if more is needed twist 1/2 out of the other thus moving the cam angle but keeping the overall cable length the same. You will soon reach a point where your tail right becomes a tail left (within three or four half twists in each of my cases) or vice versa depending on your situation. Now just note which position had the shortest tear and leave it in that position. Now all you have to do is make very very very slight adjustments to your rest to get perfect holes. I moved my rest maybe 1/64" or less and it took out the remaining 1/4" right tear. If it's a crappy day you can move back to 7 yards like I did and really fine tune it. The fourth picture is of paper tuning results at 7 yards in my garage. I've found if you can get bare shafts and fletched arrows to shoot perfect holes from 9 ft to 7 yards you will rarely have to move anything more than a very small fraction of an inch for any of the other tuning methods.
Now it's time to go outside. The fifth picture shows the results of my bare shaft and walkback tuning. When I was only bare shaft tuning the bare shaft was flying so straight I was nock hitting with the bare shaft!! I did make a very very small bump tho the right to achieve this (so small it was hardly noticeable). The walkback tuning fell straight in line with no adjustment at all after I bare shaft tuned at 20 yards with the small adjustment noted. Some people may get picky and tell me I needed another bump back to the left but plaes note that a) all these arrows are within 3/4" vertically back to 40 yards and thats great shooting for me so I wasn't ready to adjust based on that b) there was a steady wind in the direction of the slant and c) I saw how straght the bare shafts were flying. I decided to check with 50 yard fixed blade braodhead tuning and those results are in the next picture. Needless to say I was very pleased. Impact points were exactly the same at fifty yards and I have since checked at 60 with the same results. The only adjusment I made after paper tuning was probably a less than 1/64" bump right.
The last shot is my favorite and in my opinion proof that Bowtech is on to something special this year. Unless you tune alot of bows you probably will never know how rare this shot is. It's like a Unicorn or a five leaf clover...many of us have heard of it but never actually seen it. I'ts incredible that you can tune a bow this well adn have everything line up this well. The nock point is almost level with the berger holes; the arrow is lined up straight down the center lining up with the stabalizer and amazingly the sight pins are in perfect alignment with the arrow. I can tell you from experience that there are very very few bows that will do this and shoot this well to boot.
Last two short comments. When drawing the bow there is no noticeable "twist" in your hand when the cables begin to take weight like alot of modern bows. I have never slapped my arm with this 6" brace bow yet and I've shot alot outside with a heavy coat on.