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Switchback XT Cam replacement made bow WAY out of tune!

1470 Views 12 Replies 6 Participants Last post by  ClearProp
I was told that replacing the cam from a 28.5 draw length to a 27.5" draw length would not change my specs. I didn't twist anything and the cams are both highlet off.

It did change things:

It shortened the ATA by about 1/16-1/8"

It moved my cam timing from ever so slightly towards the string to way out pointed back to the riser.

It did shorten the drawlength (a liittle bit more than needed.. look like I'll be on the hunt for a 28" cam now...:wacko: )

Why did this stuff change?
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Because you need to try and twist the cable and string to get the cam back in time.

Right now it is out of time because when you press the bow and put on a shorter cam your strings and cable are in a different position.

Line up the timing dots on the cam, this is done usually by twisting the cable and untwisting string or doing the opposite, and you should be good to go.

The bow will get right back into spec.
 

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Discussion Starter · #3 · (Edited)
xswanted:

Thanks for your reply, I understand how to tune it again, but I don't understand how/why it went out of spec after so many people told me it would only change my DL and not ATA and CamTiming

btw, GO SIOUX: I went to UND
 

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Bro you REPLACED your cam of course it will change the timing. The cam is smaller than the one you took off. put some tiwist in the cabel and in the string to bring the timing and ATA back into specs. It's like this when you change tires on your truck you still have to get the new tires balanced right.
 

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xswanted:

Thanks for your reply, I under how to tune it again, but i don't understand how why it went out of spec after so many people told me it woul only change my DL and not ATA and CamTiming

btw, GO SIOUX: I went to UND
Just the nature of the beast. I changed strings on my DXT this summer and I had a heck of a time trying to get it back to where it was. Anytime you take a bow apart that far and put it back together you will have at least minor changes in timing and what not.

Once you get it back into time it should be a half inch shorter than your 29 cam was.

When did you graduate?

Class of '06 here.
 

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Discussion Starter · #6 · (Edited)
I originally had the 28.5 cam and now I'm using the 27.5 so I should have shortened the length by about 1 inch which I'm finding out now is a bit on the shorter side.... thus the reason I will be looking for a 28" cam now.

In order to lengthen my ATA and bring the cam timing back toward the string, I believe I need to UN-twist the string on either end a full turn and see where it ends up.

I Grad UND last December
 

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Discussion Starter · #7 ·
Before the Cam Switch:

ATA on REST Side 31 & 1/16"
ATA on RollerGuard Side 31 & 1/32"

CamTiming with straight rule was towards the string by about 3/32" to 1/8" by the nock when compared to the string position by the cam.

After replacing the Cam the ATA was shorter and camtimnig was off towards the riser this time but by a good 1/4"!!

I UNtwisted each end of the STRING one FULL twist.
That wasn't enough so then I TWISTED the CABLE one HALF twist.

This brought the CamTiming to straigh and level with the string.
This brought the ATA to"
1/32" Less Than 31" on Rest Side
1/16" Less Than 31" on RollerGuard Side

Making the ATA 3/32" LESS on both sides than what it was with the other original cam.


I still need to shoot the bow in and then take new measurements.... but everyone who told me before that everything would remain the same and the drawlength would change, must not have swapped out a cam before?
 

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The cam does not change anything but DL, but if the string or cable gets untwisted slightly, it can cause changes. Just set it back to normal specs, its not hard.:wink:
 

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Discussion Starter · #9 ·
With good intentions:

I'm just wondering how can it be said that it doesn't change anything but DL when it just did.

I was extra carefull as to not twist ANYTHING when replacing the cam.

I'm getting the bow back into spec, but it doesn't make sense that I should have to when it's not supposed to change anything.

I supposed I could call Mathews and see what the think about it.
 

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With good intentions:

I'm just wondering how can it be said that it doesn't change anything but DL when it just did.

I was extra carefull as to not twist ANYTHING when replacing the cam.

I'm getting the bow back into spec, but it doesn't make sense that I should have to when it's not supposed to change anything.

I supposed I could call Mathews and see what the think about it.
theyall lied to ya. if you change anything on a compound bow you have to retune everything because everything will change. thats the truth..

now get over it and tune it. :):):)
 
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