I know there are many folks here that can answer this better than I can , so I'm subscribing for the information [emoji106][emoji106]

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You can’t yoke tune a prime BecUse they aren’t independent of eachother. Too bad!

 

The top and bottom cams aren't independent? Or the two, parallel cams are not independent?

 

So, if there was no coronavirus...I would ask you to drive up to Palo Alto, and we could do this together. So, not gonna happen, so we gonna do this electronically.

1). SHORTEN THE STRING...you shorten the draw length, you INCREASE holding weight, you LOSE draw weight...that means you twist up the string SHORTER, the draw weight drops LOWER.
Now, wait just a sec. EVERYBODY knows that when the "strings stretch", you LOSE draw weight.
WRong. When the BOWSTRING..that's the piece with the peep sight, the round pipe you look through in front of your eyeball, if the BOWSTRING stretches..
PART A or PART BL(ower), or PART BU(upper...if ALL three parts of the BOWSTRING stretches LONGER or
ONLY PART BL(ower) stretches LONGER or
ONLY PART BU(pper) stretches LONGER or
Part BL and Part BU both stretch LONGER...if Any Parts of the bowstring STRETCHES LONGER....you GAIN draw weight.

No way. Everybody knows that when the "strings" stretch, you drop lower in draw weight. No. One more time. The BOWSTRING (all three parts), controls cam windup.
Cam windup is like a WATCH spring. A LONGER bowstring, allows the cam to windup MORE. When the cam is allowed to rotate MORE to get to full draw
(longer string, means more cam rotation), MORE cam rotation means MORE bending of the limb tips...a LONGER bowstring, means MORE draw weight, MORE draw length, MORE arrow speed.

Bowstring = Part A, and Part B-upper and Part B-lower.

 

I was hoping I'd get a Nuts&Bolts explanation! I'd still take you up on the offer after this virus passes. There's a lot to learn in this archery world!

So, A + B-upper + B-lower = BOWSTRING. I was thinking of B-Upper and B-Lower as yokes because they split the load from the bowstring to the two cams, but perhaps this is introducing confusion on my part. On a bow that doesn't have parallel cams, the bowstring wouldn't be split by parts B-upper and B-lower. It would just feed directly onto the single cam. So of course this wouldn't be a method for yoke tuning.

Thanks!

 

C and D are really just control cables. One's not a buss cable in the sense of a one cam or hybid cam. I do refer to E as the mini-buss or mini-yoke, but only because of the way it attaches to each side of the cam...similar to a Mathews and PSE Evolve cam.

And yes, C and D control timing, but the mini-yoke isn't for yoke tuning on this bow. B is just the end of your string, which you labeled as A, and you got correct.

 

Phew. I got one thing right! Thanks for the help!

 

Should I be adjusting the length of those yoke legs? I can imagine that I shorten or lengthen the yoke legs, the donut will be pulled left/right and I will introducing more/less tension on the cable as it feeds into the cable guard.

 

You have a bowstring. Bowstring has a center section (Part A). The bowstring has two tiny tunnels (pipe). So, B-upper and B-lower runs through the short pipes. The Bowstring, is Part A and Part B-upper and Part B-lower.

 

You don't need to adjust the length of the yokes. Only twist them as needed to keep the donuts aligned at rest and draw. If you are wanting to shorten/lengthen the string to affect draw length or weight, you should be twisting/untwisting the bow string between the donuts.

Conversely, if you want to tinker with cam timing, you need to twist or untwist the cables (again, not the cable yokes after the cable donut).

 

Great, thanks for the info! Can you explain what you mean by "twist them [yoke legs] as needed to keep the donuts aligned at rest and draw"? What are the donuts aligned? Right now, the donut is pulled outwards, as the cable feeds into the cable guard.

 

In your picture, between B and A is the string donut. Fed through the donut hole is the string yoke. When you draw the donuts will sometimes rotate and not be aligned straight to the riser. To combat this you just twist/untwist the yoke legs until the donut is relatively straight at full draw.

I don't have experience with the black series or the cable donuts, but since the cables aren't being torqued, then the donuts shouldn't be rotating on them (I think).

 

Ahh. I gotcha. You were referring to the "string donuts" (the part linking A and B) staying aligned. If those were rotating through the draw cycle, the peep sight would rotate as well. An obvious problem that would be worth addressing with adding or removing twists from the string (part A). As Nuts&Bolts points out, shortening/lengthening the yoke legs will not fix the problem as the legs are not fixed on the donut. The donut will always "self center" because it is free to slide on the string.

 

Back to this photo.



On this hybrid cam bow, if the bow ATA is too long, if the peak draw weight is too LOW...maybe we need 10 twists added, to shorten the ATA to spec, to bring draw weight up to SPEC. So, a newbie tuner might add ALL 10 twists to just the LONG leg, the bottom end loop. Increased twist pressure ALL at the bottom end only, so the tug of war is bad at the TOP end, and the SHORT yoke legs get all ugly, all TWISTED up like a candy cane.

The FIX, is to spread about the 10 twists, to ALL three end loops, to BALANCE the UPPER part and the LOWER part twist pressure. When you spread around the twists, to all three end loops, the yoke legs get pretty.

So, back to Prime Lingo. If we leave the bowstring Part A alone, then, we have to tweak B-UPPER twist pressure, to square up the B-UPPER pipe. Then, we have to tweak B-LOWER twist pressure, to square up the B-LOWER pipe.

 

If we leave the bowstring Part A alone, then, we have to tweak B-UPPER twist pressure, to square up the B-UPPER pipe. Then, we have to tweak B-LOWER twist pressure, to square up the B-LOWER pipe.

Whew. My head hurts, but I think I'm following to this point.

d_rek, it sounds like N&B is confirming what you described; adding twists to the yoke legs (Part B) will square up the two string "pipes".

I appreciate all of the help so far, but I am still not clear why the sticker on my limbs has three, very different lengths listed under "yoke".

My yoke legs (Part E, the ones that go around the cable donut) are a single piece. Might the three lengths refer to E-upper, E-lower, and B (Upper or lower?)?

 

The industry's terminology sure makes it hard for a newbie like me to follow along. Thanks for deciphering the Prime table for me.

Now when I look at the order form for Winner's Choice strings, everything goes to awry. How's my attempt at a translation?

String Length = Bowstring (AKA Part A), 27.875"
One Cam String = Upper OR Lower bowstring section (that feeds through the pipe, 35.63" for upper OR 32.88 for lower)
Two Cam String = Upper AND Lower bowstring section (that feeds through the pipe, 35.63" for upper AND 32.88 for lower)
Non Split Buss Cable = LONG cable leg (33 1/8") Shouldn't there be two of these?
Split Buss Cable = U-shaped cable that goes around the Large donut (17"). Also, two of these?

Complete Set = One bowstring (AKA Part A) @ 27.875", 2x Bowstring sections: 1@35.63" and 1@32.88", 2x Long cable legs @ 33 1/8", and 2x U-shaped cables @ 17"

Something must be wrong because the pricing wouldn't match my descriptions (cheaper for one cam string than two). This just seems unnecessarily confusing!

 

Do online chat with Winners Choice for WHAT number to put in the ONE box for string length. Makes ZERO sense to have ONE box, when you have FIVE different specs, for a PRIME bow.

 

To summarize, here's an updated diagram with lengths of the cables/strings, using a combination of Nuts&Bolts and Prime's terminology:

 

To summarize, here's an updated diagram with lengths of the cables/strings, using a combination of Nuts&Bolts and Prime's terminology:
View attachment 7134215

Change the BOTTOM left text box to read "Lower Bowstring Yoke". You should receive seven (7) pieces from Winners Choice.

 

And to summarize the discussion on tuning:

TIMING is adjusted using twists in the long leg cables.

You CANNOT yoke tune a Prime Black 5 as the string yokes DO NOT attach to the axles on the outside of the limbs.

L-R tuning can be achieved by using cam spacers. I've also heard that you can do some tuning us the Flexis cable guide (Not discussed on this thread, yet).

 

1) install d-loop, such that when the riser is vertical, the arrow is horizontal.
2) set arrow rest height, so that center of arrow matches center of the arrow rest holes...this is a good place to start
3) clamp a 2nd arrow tight to the riser wall. this becomes your reference for dead straight ahead. move arrow rest sideways, until arrow on the arrow rest, runs parallel to the 2nd arrow
4) shoot at a shoulder high target 20 yards away, aim at top edge of a level strip of masking tape. Want fletched and bareshaft to hit at the same height. Like this.



If you aimed at the top edge of the tape, and you have a mis-match for HEIGHT of impact, for fletched and bareshaft, you have to mess with cam SYNC...but, newbies and not so newbies call it "timing".
Cam SYNC, means you pick ONE cable and make it longer or shorter. Leave the other cable alone. WHY? Cuz, we are going to WIND UP or UNWIND one cam, and this changes nock travel,
and changing ONE cable either a half twist longer, or half a twist shorter...CAN and WILL tighten up the vertical miss pattern. Yeah, half a twist actually has an effect. You might need 1 full twist to get to HERE.

 

DOh! Damn copy and paste! Here's the updated diagram:

 

DOh! Damn copy and paste! Here's the updated diagram:
View attachment 7134221

Nice work!

 

You guys are killing me. It took you dozens of posts to describe/figure out what I described in a few sentences earlier in this thread.

 

and he finally has it figured out, in lingo he understands, and now he is ready to order some custom strings from Winners Choice, and he is confident he will get what he needs, in all five sizes.

 

tagged

 

Nuts&Bolts, I didn't get a chance to really take in the tuning guide until now. Thank you! This is very helpful because it is specific to my type of bow.

I'm curious what your thoughts are on using the Flexis AR to adjust L-R tuning. Would moving it in/out be analogous to adding/removing twists from the cables? i.e. adding/removing tension to them?

This video from Prime mentions it briefly. Skip to the 2:54 mark for the discussion of the Flexis AR
https://www.youtube.com/watch?v=UkP_7hJ3rFA

Also, d_rek has posted some helpful info on tuning with the Flexis AR:
https://www.archerytalk.com/vb/showthread.php?t=4316417

 

Flexis AR is for tuning centershot. But loosening/tightening it you remove/add side load to the cables, which effectively moves your centershot left or right.

The ideal way to use it to tune centershot would be to first set your centershot with your rest and nock point, then use it to microtune centershot. Start with the flexis AR completely tightened, then in 1/2 to 1 full turn increments start backing it out until your POI is where you want it.

Also know that it also makes the bow more or less forgiving of form. When it's all the way tightened down, it will be less forgiving, backed out a few turns, more forgiving.

 

What is the benefit of the O ring above the cam?

 

evenly distributes the yoke to the attachment points on both sides of the cam.

 

Tag


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Here's an annotated version of the closeup on the bottom cam:

 

So I started playing with tuning today and have a couple of questions.

In Nuts&Bolts' example, you initially set the rest and nock point by approximating centershot with arrow parallel to the riser. Then, adjustments in vertical nock travel are made my adjusting timing (twisting/untwisting) one cable. Left and right adjustments are made by twisting BOTH cables.

After getting new stings and cables installed, I shot a group of fletched arrows and a bareshaft. Bareshaft hits high and left.

Using the Nuts&Bolts method, I add twists to ONE cable. That seems to sort out the barwshaft hitting high, however, now the timing marks on my cams are out of whack. I understand the concept of results-based tuning, but I have to imagine Prime put those marks on there for a reason.

So I continue on, now targeting L-R adjustments. The bareshaft hits several inches left and has a visibly nock-right flight. I twist up BOTH cables and can start to creep it back over to the right.

So now im shooting decent groups and bareshaft is grouping, but every now and then I get a flyer out to the left with the bareshaft. I don't claim to be an excellent shot, but part of me wonders if it could be timing related.
Also, with the shortened ATA, and lengthened brace height/draw length the letoff has also decreased noticeably.

should I be considering changes to my rest and nock hight to work out the Up-Down and L-R adjustments? Or is twisting/untwisting cables the right way to approach this?

 

Bareshaft hitting left. DID you play with tightness of the roller guard?

 

10-4. Thanks for the help guys. I'll give it another go today and report back.

 

Made some progress yesterday. Took twists out of the cables to get timing marks aligned again, and tightened down the Flexis cable guard. My bareshafts were then hitting just a couple inches high of fletched arrows, with a nock low trajectory. I brought my nock point up about 1/8" and it brought bareshaft together with fletched group with a pretty flat trajectory, maybe just a touch nock high.

What I'm now seeing is that my ATA length is a little on the long side (1/8" long, but still within spec) and peak draw weight is about 2.5lbs light. I don't yet have a way to measure draw length, but I'm guessing it would be short.

I tried adding a twist to BOTH cables to tighten things up a bit but for some reason, this throws off my timing marks. Is this expected? The way I understood it, if I were to shorten BOTH cables with a single twist, it should not affect timing. Only ATA, draw weight, and DL.

Am I misunderstanding the concepts here or missing something? At the end of the day I'm getting decent groups, so maybe I should just let it be.

Thanks

 

IGNORE the timing dots. Timing dots will ONLY match, if you confirmed that both cables are exactly the same length under tension, before you installed the cables.
IGNORE the timing dots. Timing dots will ONLY match, if both limb bolts are the exact same number of turns away from max.
IGNORE the timing dots. Timing dots will ONLY match, if both limbs are exactly the same deflection.

So, how do I know my bow is IN SPEC, if I IGNORE the timing dots? Forget spec, and focus more on shooting results. Huh? What do ya mean by shooting results?
Shoot arrows, like this. 20 yards. Shoulder high target. Horizontal strip of masking tape. Aim at the top edge of the masking tape.



One fletched and One bareshaft arrow. So, ignore the ANGLE, cuz you might be using a bag target. FOCUS more on the height of the impact for the two arrows. If the HEIGHT of impact is different, then, you have to tweak the half twists in ONE cable. Pick ONE cable, and you figure out if you need to add or remove a half twist. Yes, a half twist will make a difference you can see at 20 yards. Do enough half twists, in the correct direction, and you get this result.



K. BUT, what about my timing dots? They are mis-matched and it just LOOKS ugly...you know, gots to have matching TIMING dots.

1) If your form is whack, the timing dots will not match. What is whack? Excess pressure from bow hand at top of grip or excess pressure at bottom of grip.

2) Limb bolts are mis-matched. If one limb bolt is 1/8th turn, 1/16th turn more or less than the other limb bolt, timing dots will not match. BUT, I gots to have my timing dots match. The LOOKS of my timing dots are more important than my groups. Gotta LOOK good, when shooting. FINE. Then, you can use the limb bolt (ONE limb bolt) to make timing dots MATCH. Take ONE limb bolt (you have to figure which one), and remove 1/16th turn, remove 1/8th turn, so ONE limb bends more than the other limb, and keep tweaking that ONE limb bolt, until your TIMING dots match. Now that your TIMING dots match, and it LOOKS good at brace, go shoot again.



Ah man. You mean I gotta press the bow again, and do the half twist thing on ONE cable??? Yup.



K. Got this result again, but my TIMING DOTS are not matching again...less mis-match than before, but still, my TIMING DOTS look just UG-LEEEEEEE.
K. TWeak ONE limb bolt again, to make your TIMING dots pretty again. You are fine tuning ONE limb bolt, to get both limbs to bend EQUA-LEEEEEEE. Go shoot again.

Dang it. Got this again.



You know what to do. Press the bow, and tweak ONE cable, by the half twist, until you get this.



But, u know what happened, my TIMING dots don't match, they close, but they don't match. Do this enough times, and you will either FIND the exact amount to tweak ONE limb bolt, to get EXACTLY the same limb deflection, that compensates for your whack bow hand, which might be exerting un-even pressure, so that your timing dots MATCH
and you get this result.



Most folks leave their bow hand be as-is, and MOST folks eventua-LEEEEEE give up on matching timing dots, and just settle with tweaking ONE cable by the half twist,
until they can shoot groups like this.



Fixed blade broadhead, fletched field point, bareshaft field point...20 yards by schuler26.

or this.



Target arrows, bag target at 30 yards by flopduster.

 

Thanks Nuts&Bolts. One clarification: the timing dots are measured with the bow at rest, so my firm shouldn't have anything to do with it. Also, I have both limb bolts completely tight.

Would my logic be correct to do the following: align timing dots as rest (verifies cams are sync'd) than add twists to both cables to bring ATA, draw weight, and DL to desired spec? I'm getting decent groups now with the timing dots aligned at rest, just looking to get back those fews lbs of draw weights and DL that I lost without throwing off the timjng/sync. Does this approach preserve cam timing if I add the same number of twists to both cables? Why don't the timing dots align if I'm twisting both cables the same amount?

 

The timing dots at brace, controls the amount of bending on the limbs at full draw, so your firm has an effect on the bending of the limbs.
So, yes, the timing dots may or may not match, based on your firm at full draw...cuz your firm affects bending at full draw, and the amount of bending at full draw is a function of the starting cam rotation at brace.

 

Why don't the timing dots align if I'm twisting both cables the same amount?[/QUOTE]




The top and bottom cam are different sizes so they take up string at different rates. You’ll have to play with the ratio of twists to get them to match. I believe my Ct5 was a 3-1 ratio. Work on one cam at a time. Put some twists in and write down how many (so you can take them out if needed). Take the bow out of the press and see which way the cam moved. If it’s moves the direction you want but isn’t all the way there, put another half twist in and check to see how it moves again. If it’s too far, take a half twist out until you get to where you wanna be. When you get that one where you want it, move to the other can and do the same thing. BUT write down everything you did, so you can back track if you need to.


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Great, thanks for the help guys. Good to know I shouldn't be expecting timing dots to match after cable tuning. Seems like the only way I could get them aligned was removing twists from cables, but then I was giving up draw weight and DL.

Back to it. Starting to see some improvements...

 

I was able to get bareshafts grouping tightly with my fletched arrows yesterday. I went with d_rek's advice and here's what ended up working:

• Set the bow to factory spec ATA

• Make sure cams are timed and in sync

• Set centershot to 13/16" from side of riser, arrow covering top half of Berger hole

• Set nock approximately level so that it’s square to string and rest

• Tighten down roller guard all the way

At this point I found that my draw weight was a little low (57.5lbs instead of 60lbs), so I added a few twists to both cables. This brought my timing dots slightly out of alignment, only about 1/16" off.

• Shoot into paper. (Instead of paper, I shot fletched groups and bareshaft at 20 yards watching for point of impact and bareshaft flight/trajectory)

This was the key piece of advide: Try to tune out your tears with rest, roller guard, and nock height adjustments, in that order, before you start messing with cables. You should be able to clean up your bareshaft paper tune almost all the way using just these adjustments. If not double check factory string specs and start over before starting to twist/untwist cables.

I found that my bareshafts were hitting high, with a nock-low flight (or tear if I were shooting paper). The rest height looked good relative to the Berger hole, so I experimented a couple times with nock height and found the sweet spot at around 1/16" higher than where I had originally set it. Bareshafts started flying flat (bullet hole through paper) and grouping with fletched arrows at 20 yards.

Per the advice of others on this thread, I didn't sweat the timing marks being slightly off. Also, I didn't end up messing with roller guard at all yet since I was getting good groups with it tightened all of the way down. I may experiment to see what effect it has on forgiveness, but right now I'm happy.

Thanks again to all those who contributed to the discussion. This has helped me (and hopefully others) out alot!

-Beau