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How to tune a Mathews bow with top hat shims

Mathews Halon X in bow press

All photo credits: Chris Neville

Mathews, Inc. produces several quality hunting bows, including the whole Halon lineup which has been out for a few years. For 2018, the brand new Triax has been wildly popular due to a variety of factors, perhaps most notably it’s compact size, speed, and being almost totally vibration and noise free. Mathews has a killer line of bows and, if you are still in the market for a new bow, I highly recommend you get to a local pro shop and shoot one.

I’ve been shooting and hunting with the Halon X since it came out in 2016. I love the way it holds and I have taken a couple great bulls with it over the past two years. When I first set my Halon X up, I set my center shot to about 13/16", ran the arrow at a 90° from the string through the berger hole and, just like that, bullet holes through paper. I went out and shot it several times as I sighted my pins in and it shot great. Fast forward a few weeks and I started to read and hear about a few guys having tuning issues. That’s when I started hearing how a “top hat” adjustment could really help with tuning the recent Mathews bows. I began doing some reading and it was tough to find a detailed description of what the top hats were, how to adjust or change them and why you might need to. After a few years of playing with these bows and setting up many of them for myself and friends, I have a good understanding of the top hat system and I have to admit I really like it!

So what is a top hat?

Assortment of different Mathews top hats

If you look at your Mathews Halon or Triax bow you will see what looks like a black spacer or washer that sits on either side of each cam. You will notice that the spacers have different thicknesses, typically with the thicker one on the right side of a right-handed bow and on the left side on a left-handed bow. Those spacers are what’s considered the top hats. They actually have a portion that slides inside your limb like a sleeve. The spacer part sits on the inside of your limb between it and your cam and then your axle actually slides through the limb and top hat on both sides. If you pull one out you’ll see it looks like a little top hat, hence the name.

So, who cares?

In reality, the top hat system is a genius, relatively simple system to help you find the best possible tune for your bow. Your Mathews bow is likely to tune out of the box with minimal adjustment, provided you have a proper grip, the rest is set to the right-center shot and height and your nocking point is close. But, in some cases, I have seen bows that seem to get a left or right paper tear when tuning. I have also shot broadheads that just seemed to fly left or right. You can move your rest one way or another to tune that out, but, sometimes, it’s nice to leave your rest at a center shot distance that gives you plenty of vane clearance and use the top hat system to tune those issues out.

Here’s how a top hat kit works

Mathews top hat kit for tuning

Top hat kits can be purchased for about $50 from any pro shop that carries Mathews bows or even from an online retailer like Lancaster Archery. A top hat kit is going to come with 12 top hats (six sets) that will vary in thickness. The thickest one and thinnest one make a pair, so on and so forth. You do not want to install top hats that are not a pair, meaning that, together, the spacer set would be greater than .175".

Organizing Mathews top hat kits

Once you have your top hat kit, I like to line mine out in sets or pairs so I know which ones go together.

Now let’s say that you set everything up on your bow and you shoot some arrows through paper and you are getting a left tear, meaning the point goes through the paper and the tail of your arrow is tailing to the left. First, you can move your rest to the right in very small increments to see if it cleans it up. If you can’t clean it up without moving the rest too close to the riser (right-handed shooter), then it’s time to move to the top hat system. If you are getting a left tear, then the cam needs to move to the left. If you were getting a right tear you need to move your cam to the right. You may not need to move both cams. Often, if you start by moving the top cam by changing the top hats, it will take care of the issue. If it doesn’t, try moving the bottom cam over as well. I’d recommend you start with the top cam and then shoot again before moving both cams.

How to install the new top hats

Removing top hats

Removing limb axle off Mathews Halon bow

First, you’ll need to press the bow. Once the bow is pressed, use an Allen wrench to unscrew the set screw on the outside of your limb.

Removing screws on bow axle

Gently pull that out, then carefully pop the small black washer on the outside of the limb out. You’ll then be able to look inside the limb/axle hole and see the axle running through.

Removing bow limb axle

Take an Allen wrench slightly larger than the diameter of the inner axle and use it to carefully push the axle through the limb, out of the cam, and through the opposite limb.

Limb axle removal on Mathews bow

Be prepared to hold onto the cam so it doesn’t fall as you push the axle through.

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Setting Mathews bow cam to the side

Once you have the axle out, place the cam, with the strings still loosely on, on the edge of your press or, better yet, let a buddy hold it.

Cam removed on Mathews Halon bow

Axle and cam removed.

Using allen wrench to remove Mathews top hats

Then, from the outside of the limb, you can slide an Allen wrench on the inside edge of the limb and push out the top hat to the inside of the limb.

Mathews top hat removal

Once you get it started you can pull the top hat out on the inside with your fingers. Do the same thing on both sides so both top hats are out.

Installing the new top hats

Installing bigger sized Mathews top hat kit

Now, install the new top hats by sliding them from the inside back into the limb. Remember: if you had a left tear you want to put a thicker top hat on the right side of the limb and the corresponding thinner top hat on the left...meaning you are moving the cam to the left. If you are getting a right paper tear, move the cam to the right.

Installing bow cam back on limbs

After you have put the top hats back inside the limb, the next step is to put the cam back in between the top hats. After the cam is back in, slide the axle from the outside back through the limb, through the cam, and through the other limb.

Placing limb screws back on Mathews bow

Then place the outside black washer in the outside of the limb and screw the set screw in.

In conclusion

The top hat kit has a variety of size options, which is great because you can really fine-tune your bow by moving the cams slightly one way or another. Like I previously stated, start with the top cam first, shoot it to test your results and then move to the bottom cam if you have persistent issues. You will need a press, but the whole process is very simple and takes less than five minutes.

Paper tuning mathews bow after adjusting top hats

Paper tuning my Mathews Halon X bow after adjusting top hats.

To conclude, I’ll give you a real-world example of how this can work. I recently helped a friend who has a Halon 32 who was trying to get his fixed blade broadheads to fly. He was having decent results, but when he shot out to longer yardage he was seeing his broadheads hit a few inches right of his field tips. Broadheads hitting right of field tips would mean there is a tail left paper tear. We could have moved the rest over to the right a bit and, then, after getting the broadheads and field tips hitting together, we could have moved the sight to the right to re-sight the pins in. But his rest center shot was fairly centered in the riser and moving the rest over would have given him less clearance for his vanes. So, instead, we put the bow in the press and switched out the top hats, moving the cam ever so slightly to the left. He then went back out and shot and found that his broadheads and field tips were hitting together and with a minor adjustment to his sight he was pounding out to 80 yards and still had a rest centershot location that provided plenty of clearance for his vanes. The Mathews top hat system really does give you the opportunity to fine-tune your equipment.

If you don’t shoot a Mathews or even if you do and don’t use the top hats to tune, I have included a quick set of references to help you broadhead tune your bow.

Broadhead tuning your bow

Issue Paper tune cause Rest fix Mathews top hat fix
Broadheads hitting left Paper tune tear - tail right Move rest left Move cam right
Broadheads hitting right Paper tune tear - tail left Move rest right Move cam left
Broadheads hitting high Paper tune tear - tail low Move rest down or
move nock point up
N/A
Broadheads hitting low Paper tune tear - tail high Move rest up or
move nock point down
N/A

After you make adjustments to your rest to get your field tips and broadheads hitting together, then move your sight to re-sight in your pins. This method will ensure your bow is well tuned (good paper/bare shaft tune) and your broadheads and field tips hit exactly where you want them to!

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5 Comments

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Ryan H. - posted 2 months ago on 08-27-2018 03:58:17 pm
goHUNT INSIDER

@Trail,

It wasn't my intent to bash Mathews. It's just that everyone has differing opinions on why a setup won't tune. Arrows, broadheads, grip, bow not tuned......take your pick. I have to consider all these and now I have to add "top hats" to the list of reasons why I'm having so much trouble. It's probably all me but I don't know for sure. Perhaps you could have me over for some grip work! :)

Jake G. - posted 2 months ago on 08-27-2018 08:26:12 am

I'm not sure why Ryan is upset about being able to adjust top hats that will accommodate his form and grip to achieve perfect arrow flight? Everyone's build and form is different, so that's pretty tough to find something that works for everyone if that's what he means by "fix at the factory." Whether you're an archer or rifle hunter, you owe it to yourself and the animals to spend some time with your equipment tuning, practicing and becoming familiar with your weapon.

trail
Trail K. - posted 2 months ago on 08-27-2018 07:29:53 am
goHUNT Team

@ Ryan H

Sorry you are having trouble with your Triax. In terms of tune, I'd say better than 90% of the bows from the factory tune right out of the box if they are setup properly. In some cases, perhaps due to grip, hand size/shape and technique they may not shoot a perfect paper tune hole. I had a friend over a couple weeks ago that was having issues and with a little work on his grip he was shooting great. Perhaps take a look at your grip, if you feel like your grip is good, the pro shop you bought it from should be able to work with you to get it figured out. I'm betting with a top hat switch or some minor grip adjustments it will tune right up.

Ryan H. - posted 2 months ago on 08-26-2018 07:09:00 pm
goHUNT INSIDER

Great! Just what I need, another thing to try to fix to get my bow tuned. Why can’t Mathews fix that at the factory? My Triax is giving me such a fit I’m on the verge of becoming strictly a rifle hunter. Seriously, shooting my bow isn’t fun anymore.

Dominick A. - posted 2 months ago on 08-21-2018 09:46:59 pm
goHUNT INSIDER

I have a Halon and Halon X and do most of my own work. This is one of the best decriptions and instructions I have seen. The is to much hype about how easy to tune other bows is. So what if it takes some time. It is not like you have to do it more than once.