# hoyt proelite spiral cam nock travel ???



## DaddyPaul (Oct 24, 2003)

It is kinda hard to tell from the pictures but to me it looks like the top cam is under rotated a bit. I can see the peg on the bottom is touching the cable but the top cam looks as if the cable isn't fully seated flat in the groove. Try putting a twist in the buss cable or take a twist out of the control and see how she does.


----------



## P&Y OHIO (Apr 30, 2008)

*Nock Travel*

That's interesting...first time I've seen the nock travel graphed in that manner for the spirals

Are you 90 degrees to the string at static for your nocking point?

Nock travel has been addressed a lot here w/ Hoyt's cam and a 1/2 system

I know some like to rotate the upper cam slightly to just bump the draw stop before the lower to smooth out nock travel...I've shot all mine w/ top and bottom dead on...I prefer the harder wall and creep tuning has never shown me(and I've tried it w/ all my Hoyt's) that I needed to adjust timing! 

Would like to see the nock travel graphed w/ a nocking point raised in a series of progressions from 1/16, 1/8, 3/16...w/ draw stop timing equal, top and bottom

Then, adjust timing w/ upper cam hitting slightly before lower and go through the progression of raising the nocking points....would love to see the cause and effect results

Nock travel and cam lean also can be included, are all overemphasized IMHO

The bow in the OP's thread will drive tacks in it's current tune and has been done by many of the top archers for years

It's kind of fun and when I got the time I like to play w/ scenarios like this, it gets me thinkin :thumbs_up


----------



## edthearcher (Nov 2, 2002)

*post*



leintz said:


> Hi hoyt gurus!
> 
> I have 2004 Hoyt proelite XT3000 limbs, spiral cam 3(29,5") 60lbs
> So, I used high speed camera to record NAP Smartrest movment-anyway I got very ugly nock level movment....up to 0,5 inch
> ...


you say your cams are in perfect time. I say there NOT, your draw stop peg is touching the cable, the other draw stop is under rotated. what is your nocking point?? 1/8 is 90 degrees. all shafts when leaving a compound bow shot with a release will bend in a down ward arc. straighten than flex up ward. so if you expect the nock not to move it will


----------



## P&Y OHIO (Apr 30, 2008)

*Pics*

Those pics are questionable to say the least :thumbs_do

How many times have you checked your timing 3ft. away from the cam ? 

I'm assuming the cams are in time, cause it looks like to me, the draw stop is just off the cable on the lower cam as much as the upper cam...could be wrong though

From the graph it reads the arrow lifts up off the string then starts it descent downward to Brace...interesting


----------



## oldbuck (Apr 14, 2006)

Hello Lentz,
Please expalin how the bow is secured to your draw board during this test, this is very important. Describe your procedure in detal. I have done allot of nock travel testing and may be able to help. I rec'd your pm and asked you to call me, but your info says you are from Estonia, pretty expensive call, so we can use the forum.
oldbuck


----------



## reylamb (Feb 5, 2003)

I thought it was fairly common knowledge that Hoyts have a downward nock travel built into their cams?


----------



## leintz (Apr 24, 2003)

about the peg....

if I shoot 65% let-off then lower cam peg touches the cable
upper cam cables is in the cam's groove

but I 'm shooting 55% let-off then lower cam peg touches the cable
and upper cam's does not (lower and upper cam string parts are identical=mirrored)

maybe I'm wrong...

nocking point 90 deg.

to oldbuck: on the bow picture there is a red line=perfect center
and during the draw cycle the distance between center line and cam Axle hole are equal (blue lines)
Bow is secured =rigid construction=no defelction in construction...

Thanks guys....more ideas.....


----------



## P&Y OHIO (Apr 30, 2008)

*"Edit"*



P&Y OHIO said:


> From the graph it reads the arrow lifts up off the string then starts it descent downward to Brace...interesting


Instead of arrow lifts off string:doh:meant nock travel spikes upward

You may be able to somewhat flatten out that spike upward at the beginning of nock travel by raising the nocking point...that spike may also be caused by the upper cam being a touch off that cable relative to the bottom cam


----------



## oldbuck (Apr 14, 2006)

*A different perspective*



leintz said:


> about the peg....
> to oldbuck: on the bow picture there is a red line=perfect center
> and during the draw cycle the distance between center line and cam Axle hole are equal (blue lines)
> Bow is secured =rigid construction=no defelction in construction...
> Thanks guys....more ideas.....


The test you performed will show the nock travel as it relates to a line drawn perpendicular to the string a brace height. You are interested in the dynamic nock travel.
Draw the bow to max without clamping the riser, then after the bow rotates (as a function of Hoyts NOT level nock travel) clamp the riser. When the bow is fired the mass of the bow does not rotate, only the string and arrow move, but you will note that the bow frame has rotated prior to the shot. Now measure your nock travel, this closely represents the dynamic travel of the nock. Look at hi-speed video of bows and you will see no rotation of the bow frame during the shot, only when the shot is ended.
If this is not clear write back and lets talk. Hope this helps.
oldbuck


----------



## leintz (Apr 24, 2003)

maybe anyone can measure spiral cam's nock travel graph?


----------



## oldbuck (Apr 14, 2006)

*Nock Travel*



leintz said:


> maybe anyone can measure spiral cam's nock travel graph?


Hello Lentz,
You measured nock travel with a datum reference that was 90 degrees to the string, which is fine as measure...BUT... when you draw the bow back with a nock travel that travels up from that datum (Hoyts) the bow seeks to level it self to the two points, brace nock point and fulll draw nock point. These means that the bottom of the bow will rotate away from the archer, making the nock point travel now level but the bow out of square. Nock travel deviations measured from this new datum reference are now what the arrow sees during the shot.
oldbuck


----------



## leintz (Apr 24, 2003)

to oldbuck: ok, is it normal and how much affects to arrow flight...
how to improve this situation?


----------



## oldbuck (Apr 14, 2006)

*Change Nock Travel....*



leintz said:


> to oldbuck: ok, is it normal and how much affects to arrow flight...
> how to improve this situation?


Hello Leintz,
The nock travel is primarily controlled by the cams profile (cannot change that), then the spring rate imbalance of the limbs(That can be balanced with two matched limbs) and to a lesser degree the synchronization of the cams (this can be adjusted). After that you are essentially done with the bow. Then to improve accurracy its adjusting arrow flight via draw weight, spine, FOC and horizonal and vertical rest position and on some rests the launcher spring rate.
oldbuck


----------



## DaddyPaul (Oct 24, 2003)

leintz said:


> about the peg....
> 
> if I shoot 65% let-off then lower cam peg touches the cable
> upper cam cables is in the cam's groove
> ...


If you move the peg to 55% let off you need to adjust the stop timing so that the bottom peg touches the cam at the same time or slightly after the cable is fully seated in the groove of the top cam.


----------



## leintz (Apr 24, 2003)

DaddyPaul said:


> If you move the peg to 55% let off you need to adjust the stop timing so that the bottom peg touches the cam at the same time or slightly after the cable is fully seated in the groove of the top cam.


really ? i hope it helps...a little


----------



## DaddyPaul (Oct 24, 2003)

leintz said:


> really ? i hope it helps...a little


Sure you do. By moving the peg to the 55% hole you are forcing that peg to touch the cable a little sooner than in the 65% hole. This makes the top cam lag slightly behind in getting to the stop. Depending on DL and DW you can either add a half to full twist in the BC or take the same out of the CC. :thumbs_up


----------



## leintz (Apr 24, 2003)

thanks guys, I'm more educated now....:smile:


----------



## leintz (Apr 24, 2003)

*new graph*

the green one...

floating support...free to roll..


any comments...


----------



## reylamb (Feb 5, 2003)

I am not sure on what to comment on? Hoyt has built downward nock travel on all of their cam systems, and have been for quite some time. It is a design philosophy from Hoyt that downward nock travel will give more consistant results. There is not much you can do to change it, if anything at all. You could try playing with the rotation of the top cam to get a closer to level nock travel, but I doubt you will ever achieve it.

Personally, I believe you are overthinking this quite a bit. Level nock travel is quite overrated. Look at the results in the pro class in the NFAA and FITA events world wide. The bows flat out shoot.

I will say that your mapped DFC looks differrent than any curve I have ever seen or mapped with spirals. Every spiral cam I have ever mapped a DFC for the DFC stays flat at the top, not slowly dropping down. I am not sure what is going on there.


----------



## leintz (Apr 24, 2003)

*jep*

I'm agree...I don't waste my time any more..

thanks guys!


----------

