help with Mathews Triax cam rubbing yoke

[WhatToHunt]

Had my Triax paper tuned and shooting well last season after I had put on a new string and used top hats to fine tune. But yesterday I finally got out to do some shooting and could feel and hear something rubbing during my draw cycle. The bottom cam is about halfway thru drawing when it touches/rubs the yoke on the left side . I know the top hats are shimming that bottom cam nearly as far right as it will go. My thought is to use the appropriate top hats to re-center the top and bottom cams, make sure my rest is set to spec, check my cam timing, THEN start over with the tuning process.

Would anyone have something more to add?

I just don't want to overlook something and certainly don't want to shoot it as is. Seems juuuuust a tad dangerous.

 

[MT257]

I would be interested to see what the fix is for this. I had mine shimmed all the way over to one side using the top hats and didn’t have rubbing but that was one concern I did have after putting those top hats in. The yolk isn’t twisted way up on one side is it?

 

[WhatToHunt]

The yolk isn’t twisted way up on one side is it?

No, just double checked to be sure. The yokes look normal other than the cam being closer to the left side. Which leads me to believe the obvious solution is re-centering things. But sometimes the obvious isn't actually the answer. Ha!

 

[OR Archer]

When the strings were installed did they route them through the rollers properly?

 

[WhatToHunt]

When the strings were installed did they route them through the rollers properly?

Double checked and it's correct, but good thought just to be sure.

 

[OctoberGold]

Any chance that your yoke splitters got moved? They should be perpendicular to the string. Shimming shouldn't change the orientation of the cam vs yoke as the bearings and cams would be moving together. It would have an impact on your cam lean though.

 

[WhatToHunt]

Any chance that your yoke splitters got moved? They should be perpendicular to the string. Shimming shouldn't change the orientation of the cam vs yoke as the bearings and cams would be moving together. It would have an impact on your cam lean though.

Here's a pic if it helps. Perhaps it's cam lean? I know those top hats are shoving the cam way to the right but that was what got it to tune thru paper. The yoke isn't touching while at rest, but it rubs while drawing back. The pic doesn't show the gap very well.

 

[OctoberGold]

View attachment 305508

Here's a pic if it helps. Perhaps it's cam lean? I know those top hats are shoving the cam way to the right but that was what got it to tune thru paper. The yoke isn't touching while at rest, but it rubs while drawing back. The pic doesn't show the gap very well.

Your yoke is out of spec. Look at the serving on the right side. The right side loop is longer than the left. Pull the yoke and twist it to 13" with both loops being the same size.
Added a picture of my traverse for reference.

 

[WhatToHunt]

Your yoke is out of spec. Look at the serving on the right side. The right side loop is longer than the left. Pull the yoke and twist it to 13" with both loops being the same size.
Added a picture of my traverse for reference. View attachment 305515

That makes sense, thank you! And the pic helps. I will press it this weekend and see if I can fix it. I'll report back after. Thanks again.

 

[4rcgoat]

That makes sense, thank you! And the pic helps. I will press it this weekend and see if I can fix it. I'll report back after. Thanks again.

What was the fix for this?

 

[WhatToHunt]

What was the fix for this?

So I pressed it yesterday and took a long look at what might change if I performed twists and whatnot. But before I moved anything on it, I put in a call to the bow shop that put the string on last fall. They asked to take a look at it in case it's a warranty issue that Mathews would handle. No fix confirmed yet, but hoping to know more soon. Taking it to the shop this week.

 

[WhatToHunt]

Bow shop pressed it, pulled the axle and called Mathews. Mathews tech had the shop make sure nothing obvious or outrageous was malfunctioning. Mathews only suggestion was to swap my top hats on the bottom cam, which they did. This stopped the cam from rubbing the yoke during the draw cycle, but I'll need to start over with tuning and hoping that doesn't lead me back to "needing" top hats to get the best outcome.

I asked them about the yokes and they didn't suspect those would be the cause of my issue.

 

[OR Archer]

When you’re moving your top hats are you doing it just on bottom or both ends? I prefer to do any gross adjustments with top hats on the top cam. Then finer on the bottom. I’ve had the best results doing it this way.

 

[WhatToHunt]

When you’re moving your top hats are you doing it just on bottom or both ends? I prefer to do any gross adjustments with top hats on the top cam. Then finer on the bottom. I’ve had the best results doing it this way.

Thanks! It was several months since I had gone through the process so I can't recall what sequence I used to get there. But now I can start again.