In the process of finishing up a new bow and I am not happy with the flight I'm getting. I suspect tiller is off. Tiller is 0 at the moment. When the arrow leaves the bow, the back end of the arrow kicks down , doesn't matter where I nock the arrow on the string. I started at 1/2" above square and worked my way down past square and it was all various degrees of porpoise. Raising brace height didn't help much. I'm thinking the top limb is overpowering the bottom? I shoot 3 under, the bow is a pretty extreme reflex deflex. 43#@28" . I'm close to the 40# mark and don't wanna screw it up . Given this info, which limb needs to revisit the grinder ? top or bottom? Thanks

So.....you should be able to put the bow on a tiller board and see the limb that needs to be altered. That being said, I've NEVER seen a bow that couldn't be tuned to get good arrow flight regardless of tiller. Remember that in spite of what folks tend to think these days "proper tiller" is subjective. What does the nock locator on the string do when the bow is drawn? Does it come straight back, does it rise, does it drop?

What does the bow do when you shoot it? Does it sit dead in your hand, does the top limb tip forward severely, does the bottom limb tip forward severely? Are the nocks too tight? That's one of the first things I would check.

Also I would look at excess finger pressure on the arrow.

Nearly impossible to give you a real answer without seeing you shoot the bow.

An even tiller is likely not the issue since it would be more favorable to a 3 under hold than a positive tiller. You have something else going on and possibly the wrong spine. You also need to be testing with a vertical bow.....no cant.

I was thinking it may be under spined as well George. And yes I am testing vertical.

Attempting to troubleshoot a bow's performance without knowing all the specs of the bow and arrow is hit and miss.

The bow sounds and feels great at the shot. the nocks are pretty tight however.

"the nocks are pretty tight however." That's where I'd start.

1/2" nock point isnt very high. Try 5/8"- 3/4" dont be afraid to go higher. for me most bows tune up to 5/8". YRMV good luck

in addition to what george said. I just tuned a bow last evening and it was weak. in addition to tail left its was also porpoising. I adjusted brace height until it was shooting straight and the bad tail high I was getting disappeared.... but I suspect you are getting a defection off the shelf... just some thoughts

https://tradbow.com/archery-accuracy-and-nock-fit/

"1/2" nock point isnt very high. Try 5/8"- 3/4" dont be afraid to go higher." Actually in my experience if you are shooting 3 under and placing the arrow ABOVE the nock locator on the string 1/2" is way high.

I personally have never needed a nock that high when placing the arrow above the nock locator.

Moving the nock point up is the quickest, simplest variable to test. Like Bighorn, I shoot at 5/8 inch above or so, and a 1/2 inch would have me porpoising on several of my bows. Good luck.

https://tradbow.com/nock-fit/

Years ago when I started using 3-under and higher string nock, I chased a porpoising issue until I also changed my arrow rest to a taller rest. Issue solved. I also use 2 string nocks to prevent excess finger pressure on the arrow nock.

To eliminate porpoising I adjust one string nock and adjust until I'm satisfied with flight, and then add a second nock for insurance. I set the gap between the two string nocks wide enough that it doesn't pinch the arrow nock at full draw.

Tillering is really about making sure that the limbs are moving in harmony. Most times if the tiller is off this can be corrected by normal tuning. Nock adjustment and adjustments to the shelf. But in some severe cases the limbs need to be reworked for decent arrow flight.

ffp, im referring to the bottom of the top np. where the nock contacts the np. i use 2 np and shoot 3 under. when shooting split i usually end up 1/8” lower than shooting 3 under. but i suppose this makes a good point for when discussing this that what and where you are measuring should be clarified.

Got it BigHorn.

I am shooting off the shelf with a rug rest, When setting up a new rig i generally mark the string where i think the nock should go with a silver sharpie for a reference, then once I find the happy spot I will use one, crimp on nock set above the arrow nock. the nock is very tight to the string however, I originally had it way to loose and had to re-serve it with end serving underneath the final serving. I tried adding 4 strands to the string but it was still too loose. I need to revisit my string recipe apparently .

Sounds more like funky arrow and bad release than bow problem. Who built those arrows?

Generally the string nock height for 3-under will/can run 1/2"-5/8" from center. The nocked arrow angle shooting off the shelf may be the cause...that is, if by "rug rest" you mean just a cover on the shelf.

How long is the arrow relative to your draw length?

If the shelf is relatively flat, put a "bump" under it to make a smaller contact point or try an elevated rest.

I radius the shelf and side plate on all my bows, I have a 29.5'' draw and I built the arrows as well. You can see those in the footings thread. I put on a bear weather rest last night to elevate the arrow and flight looked much much better. not perfect but I will continue to work on it. Thanks for all the input fellas.

If the arrow flight cleaned up after adding an elevated rest, you have a spine/clearance/tuning problem.

Even bows with a tiller profile that is wildly asymmetrical can be tuned to achieve perfect arrow flight. Civilizations have done it for 1,000's of years.

BUT, if the elevated rest works for you there is absolutely no reason not to use it.

Been using 3-under for longer than I can recall. Early on, I recall sometimes having porpoising issues, usually just slight, but occurring. I eventually tracked the issue down to rest height and type in combo with string nock height.

To bring my required string nock height for 3-under down to closer to center, I started making and installing my own rests that have a bit of give and can be tweaked for height, eliminating having to change string nock height. Sometimes the height adjustment of the string nocks, depending on the bow, was no more than a 1/8th” making adjusting rest height the easiest solution.

To check for any slight porpoising, I shoot a target that is at a height that is level to the arrow point-on from a distance of no more than 15 feet and check for any slight tail high and adjust until arrow sits perfect straight (horizontal) in the target.

However, I am quite aware that what works for one, does not mean it will work for all.

"I am not happy with the flight I'm getting. I suspect tiller is off. Tiller is 0 at the moment."

The tiller measurement is a good start to balancing the bows limbs, but often times can be either positive or negative depending on where those limbs are bending.

With laminated fiberglass backed limbs that are built from the same form and materials, You would think everything should be the same, and a zero tiller provide the proper balance.

Shaping the width profile slightly different can cause the limbs to bend at slightly different locations. This As well as slightly different limb core strength, or even glass strength can throw a limb out of time and balance.

The only sure fire way to check those limbs is close examination on a tiller tree at different draw lengths. Or by using a limb balancing system referred to as "Mapping" . This is fairly simple to do. Just string the bow and put it on your work bench on a piece of butcher paper taped to the surface. Then carefully trace the limbs shape on the back of the bow limbs.... Then flip the bow end for end and match up the tracing. Then use an 18" tiller stick to hold the bow at half draw, then map it again. This will show you where the glass needs to be sanded to match the top and bottom limbs working portion to match.

Done properly, this will eliminate vibration and increase performance.

as far as arrow flight goes... you can eliminate proposing on a bow that is unbalanced just by using an elevated rest and adjustment. bottom line is tiller doesn't effect arrow flight.

.02 cents work bro.... Kirk

Take your limit off of how high you'll move your nock and see what it takes. Not one of my bows will shoot a half inch nock 3 under. Your using a setting more suitable for compound n release.

I just had an issue trying to get rid of nock high impact with bare shafts on a TD recurve that just had the limbs reworked taking pounds off. There is another thread about nock high impact here on the Leatherwall with lots of good advice. Getting rid of weak spine wasn't a problem but the nock high impact issue was.

In the end I ended up increasing my brace height 1/2", my nock set on the string is now set for 3/8" and using two nock sets. I also pulled my rug off the shelf and put down a piece of a tooth pick, the width of the arrow on the shelf and covered the shelf and tooth pick with moleskin padding instead of a regular rug. My bare shaft arrows are now shooting good, no nock high impact. I'm pleased. There was a lot of dinking around until I got to that point.

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