Spiral Cam's

[2Dogs]

Ok I have a few questions for those that have played with these cams.

When you order a Spiral and it turns up (say 30" 60#) the position of the control cable to the flat spot on the top Cam is always...just short of it. See the red line on the picture below.

From everything I've read and seen on the Cam 1/2 this is not good, as the wall can be sloppy and VNT will most likely be an issue as you pull into it.

So in order to get the cable flat against the Flat Spot on the top cam, how do you adjust your strings and cables so that you DO NOT lose poundage?

I found that you could lengthen the control cable and you would get the ideal position, but increase your draw by approx 1/2". This was ok if you wanted to use the 55% letoff post, as you would get back the 1/2 you lose when you go to that post.

So how have others setup their spirals?





http://www.archerytalk.com/vb/attachment.php?s=&postid=324487

[Marcus]

If I lose poundage I shorten my control cable to get it back. I then shorten my power cable to adjust timing and adjust my main string to get the draw length right.

[2Dogs]

Yes it's just a big pain in the arse when you are trying to order a Spiral tec bow based on your true AMO draw.

As all the Spirals I've seen come in have the AMO draw correct, but the top cam is not in the optimal position.

So when I recieved a 30" bow and adjusted it as per my method, in order to get it looking like the photo I ended up with a 60# bow at 30.5"

So are you saying you can adjust it to get it like the photo and remain at 30" 60#

[grantwomack]

An easier solution would be to just get rid of them and go buy a pair of Command Cams. :D

[Marcus]

An easier solution would be to just get rid of them and go buy a pair of Command Cams. :D
Yeah but that's like saying "Can't get your's G3's to tune, go buy some Carbon Plus limbs.
Spirals kill command cams anyday.

OK lets say you have a bow at 29.75" and 56# and you want 30" at 60#

* Add twists to the CONTROL cable. This will gain your poundage. (Result will be that the top cam will now be longer in draw)

* Add twists to the POWER cble untill the bow is timed. This will get your draw length. Make may need to do these back and forth till you get everything right.

IF your draw comes out too long:
Add twists to your BOW STRING to shorten the draw. Should have less effect on draw weight than the CONTROL cable.


Kane's Supertec was on 56# and we got that in time and at 60# pretty easy. I also converted my Cam 1/2 to Spiral without losing poundage.

[robbo]

Marcus, say you had a 60# bow @ 30"

and you wanted 56#(or60#) @ 29.5"

You just do the reverse, I assume?

[Marcus]

Yes that's right Robbo, just lengthen the cables. HOWEVER you would most likely be best off shortening the main string

[James Park]

Following a question from 2Dogs, I have given some more thought to Spiral Cams and how to ensure that timing is correct.
For a compound bow, the more rapidly we want the draw weight to change for a given increment of draw length, the faster we need to slopes to change on the cams. Hence, for a near-round wheel bow we get gentle changes of draw weight as we draw the bow, and for hatchet cams we get much more severe weight changes (faster increase at the start of the draw and a more-abrupt valley and wall).
Also, where we want a large change in weight we need a large change in the cams. For example, an 80% let-off will require a more abrupt change than a 60% let-off.
Cam timing becomes increasing more critical as the cam profiles change more rapidly. Hence, cam timing becomes increasing more critical as we ask the bow to provide a more radical force-draw curve, and as the let-off in the valley becomes greater, and as the required wall becomes harder. Hence, for example, a hatchet cam bow is more critical of cam timing than a near-round wheel bow.
The most critical part of the timing is around full-draw, as it is there that any variation the archer makes from shot-to-shot comes in. If the timing is not exact for other parts of the draw cycle it will affect the way the arrow flies, but that will not vary significantly from shot-to-shot (although it may change the way the arrow flies from week to week). Around full-draw, any timing error will show up as vertical nock travel.
We also need to consider what will happen as strings and cables slowly stretch (which is inevitable, even for some of the exotic materials we now use).
Considering a few examples:
Single cam bows: These bows usually have a reasonably aggressive force-draw curve (and hence are usually reasonably fast). They frequently have a high let-off, and a very hard wall. Hence, it is very important that the cam timing is correct. However, because the

[Marcus]

Did some more playing today and the Spirals are certainly more sensitive to being out of whack than the Cam 1/2. It's more forgiving in the sense that the wall is harder, but certainly groups better in time. The Cam 1/2 groups well out of time, but you can pull harder into a wall and throw them further.

* Spiral Cams: The hard wall means the timing will not throw as far, however a small amount out will be more noticable. Be 1 twist out and it will throw a 9 at 18m.

* Cam 1/2: easier to shoot well if out of time, but pull hard into the wall and the variation is higher.

Out of the 2 I prefer the Spirals, however if I am not grouping well (like out of the X at 18m) I need to look at timing, while with the Cam 1/2s I would have assumed it was me.

[2Dogs]

Thanks Jim.

Yeah it confirms what I orginally thought about the spirals, and how to set them up.

It does make the decision of what draw length to order with a Sprial Difficult. As every Spiral I've seen has been correct at it's AMO Draw length, but the Top Cam is out of whack and the Transfer cable needs lengthening to get it to the desired spot.

Hence if you order a 29" bow, it usually works out to be a 29 1/4 or 29 1/2. But as Marcus says you can bring it back to 29" by shortening the string..............I think :D

I found with the Spirals to set them up with a new set of strings that the following order of things got it right.

1. The Power Cable (yoke) controls the limb deflection, so I shortened that to get the bow maxed out to it's proper poundage.

2. Following 1 you will increase the draw, so then shorten the transer cable to decrease the draw without changing the poundage. And get it into the right timing (See photo above)

3. I try not to touch the string length, as doing so altered the poundage.

I'm presently playing with the Mathews Ovation, and I'm really impressed with how simple the single cam setup is on these.

[James Park]

I have certainly gained an impression that the vast majority of bows in use are not optimally adjusted and will be costing their owners quite a few points. Have occassionally wondered whether we should hold a workshop on it one day.

[Jules]

I feel like I take 2 steps forward and 3 backwards :roll:

This week I'm using correctly spined arrows which would be good if they weren't swinging all about the place off the bow. I need to replace the serving with thinner gear to loosen the nock fit on the string too.

I think that a workshop would be really interesting :)

[robbo]

It's all become very clear............................................. ..as mud. :D


As in Pauls post, twist or untwist the power cable to increase or decrease draw weight.

Twist or untwist the transfer cable to adjust the draw length.



Twist or untwist the string will change draw length and draw weight.

But does the twisting the string have as much effect as twisting the cables?

[Juggs]

my supertec came right on 27inches at 65% letoff.

which means if i adjust the cam to be correct i will have to move the letoff peg to bring it back to 27inches.

[2Dogs]

No it doesn't..........not for me.

I try not to touch the string, because the twisting can effect the Peep rotation.

Obviously the Peep is not a problem for you Robbo...........

Your Forehead Blocks the view............ :rofl:

Sorry :D...couldn't help myself :D

[James Park]

I agree with 2Dogs - change the cable lengths, not the string length, so that you do not upset the peep rotation.

[2Dogs]

Juggs

If you adjust the Transfer cable....lengthen it. Should bring it in time.

Then as Marcus said, try shortening the string a bit and hopefully you won't lose pounds.

You see what I mean then Juggs how your bow is right at 27" AMO but the Top Cam in NOT in the ideal spot. IT ****s me how HOYT have absolutely no information about this at all.

[James Park]

From my random testing of bows, my guess would be that probably 75% of multicam bows on any given shooting line would be out of time. For certain, that would be taking a lot of points off those archers.
Similarly, I would guess that about 20% of archers would be getting the rear of the arrow making contact with the launcher, also giving away points.
In each case, these points are easy to get back, without any other change to the archer's technique.

[mloncar]

i don't have spirals (i have standard cam & 1/2)... ...but still i'd like to ask something:

i have 03 ultratec with XT2000 and cam & 1/2 (cams are H6, draw stops in F posotion).. ..by hoyt charts my spec are DL 29" and 60# (since i have 50-60# limbs) - string 56.5", cables 40" and 43".. ..but my ultratec is uder spec (DL is arround 28.5", and DW is arround 57#). how can i get my bow to DL 29.5" and DW arround 52-54#????

how much the BH (brance height) changes when you twist/untwist cables or string??

[mloncar]

ttt

[mloncar]

one more question... ...the timing of my cam & 1/2 is good, my draw lengh is little too long, but if i move my moduls for one peg back it's too short.

i could shorten my string, but i'd like to know if it's possible too shorten my dwar lenght with cables?? which one??

[Marcus]

You would need to lengthen both cables, but by different amounts.

[Brad]

After reading most of the above i thought i would have no problems when i tried to change my string and cables. However when i went to loosen the limb bolt it BROKE!!!

Man what a feeling when they break. Sent the limb pocket smashing into my hand.

I just don't seem to have any luck with my equipment.

Hopefully it won't take too long to get it replaced.

[James Park]

However when i went to loosen the limb bolt it BROKE!!!
That would be altogether too much excitement for a day, especially with the draw weight you use. I have never heard of that mode of failure before.

[Eberbachl]

Holy **** man - that's a prick.

Did the Limb pocket locking bolts on the sides catch it, and stop it from blowing out completely?

I hope you get a new bolt soon :wink:

[Flame]

that is too bad just before the 3DAAA
I'm sure Luke is real unhappy :D

[Eberbachl]

Well I am unhappy if Brad can't make it.....

I certainly hope you an get a replacement and be right for the weekend Brad :wink:

The more shooters that are able to come and play this game the better as far as I'm concerned :D I really don't care if I get my arse whipped, as long as I give it my best shot :P

It's all good for the game :bday:

[Marcus]

Brad if you are desperate I'm sure I can find you a limb bolt. Let me know.

[Brad]

Yeah James it hurt! If it's going to happen to a bow it will happen to mine.

No Luke the locking nuts didn't hold it. It broke those too.

The bow has been sent back to Darryl Reeks who looks after customers very well. It will need a new limb pocket as well.

I've got a bow for this weekend and if I can get it tuned and sighted by Sat everything should be fine. Can't miss a 3DAAA shoot.

[Eberbachl]

**** - I've always wondered if the limb locking bolts would hold on!

...now I know :o

[Brad]

Don't get too worried it would probably only happen to me.

But i'd love to see you next time you try to adjust your limb bolts :D :D

[Eberbachl]

It's OK Brad, I don't own a Hoyt anymore!

So, if my limb bolt breaks, I know there's not going to be anything to hold it :D

...from now on - it'll be....

"Hey dude, could you just take a turn off each limb for me?" :D

:rofl:

[coach]

They had BETTER NOT break Luke ,as I have to do all the adjustments etc on Freestylers new bow! :D
This is the second time I've heard of limb bolts breaking on Hoyt , wouldnt have thought a bolt would break :o

[Eberbachl]

I'm just joking about it coach.

I've got 100% confidence in it :wink:

Anyway, I've already wound it down to 44lb for ya :wink:

[coach]

I know Luke , Thanks for everything you have done for my lovely wife :D Cheers

[2Dogs]

So did the head of the limb bolt snap off while you were unscrewing it?

If so.......that bloody amazing!

Serves you right for being 6'10" and a draw length around 38" @ 150
# :D....learn to shrink :D

[Brad]

Bolt broke at about half way. Half is still in the riser and about an inch and a half embedded in my hand!!

Tried shrinking but couldn't fit in the washing machine.