Archery | What is Bow Tiller?
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Archery | What is Bow Tiller?

August 12, 2019


Hey guys, this is NUSensei. Today, I will be covering the topic of what is bow tiller? And, by extension, why is bow tiller important? Tiller is a measurement. It’s measured using the bowstring and the bow itself. Now there are a couple of different measurements. The first one is brace height. That’s the distance between the string and the throat measured like this. Tiller, is the difference between the gap from the string and the upper limb and the string and the lower limb. For a one-piece traditional bow, the measurement is taken where the limbs begin to curve. For a three-piece takedown bow, the measurement is a bit easier, it’s from where the limb connects with the riser. So, here, and here. Normally you would measure using a ruler or a bowsquare, but in a pinch a lot of archers will use an arrow instead. So they measure it from here and here. If the distances between the top limb and the bottom limb are the same, that’s called neutral tiller. However, most modern bows, such as the Olympic style recurves are meant to be shot with a positive tiller. What this means is that the gap between the bottom limb and the string, is slightly smaller than the upper limb and the string. The exact difference between top and bottom limb, varies between archers and bows. When tuning a bow, you normally start with 1/8 inch difference. Although that might shrink to around 1/4 inch, depending on your tune. Using the arrow as a reference, if we take the measurement between the top limb and the string which is where my fingers are and compare it to the bottom limb and the string you can see that there is that much of a gap. So, the bottom limb, is that much closer to the string and that’s a fairly average tiller. What this effectively means is that the bottom limb is slightly heavier than the top limb. Why is that the case? The reason why a positive tiller is needed is because of the design of the bow and this reason isn’t immediately obvious. Now the bows are symmetrical. You grip the bow in the exact centre. That’s the case for balance. However, when you nock the arrow on the string and especially when you place it on an elevated rest the arrow is above the middle of the bow. So when I draw the string back, especially using a split finger technique, as standard for modern archery, when I pull it back I’m actually imparting an uneven force on the limbs because I’m not drawing the string back in the exact centre of the bow. I’m actually drawing above it and that means that this top limb is under different tension, to this bottom limb. Think about it this way. Because I am drawing the string back above the mid-point of the bow, that means the top limb is actually slightly closer to me than the bottom limb and that means when I release the string, the top limb should snap back into position, slightly before the bottom limb. Essentially, that means the limbs aren’t synchronised to borrow a compound term, and compound bows have a similar problem. When the cams don’t turn in the correct timing, one will go back before the other and that causes some issues. The same thing applies to recurve and that’s what the tiller is for. So, considering that because we are holding the bow at mid-point, but drawing it somewhere else we have to compensate for that and making the bottom limb heavier than the top limb. It’s only a very slight difference. But that should bring the limbs into synch and that means when you release the arrow, both limbs snap back in to place with the same amount of effective tension. Not every bow needs a positive tiller. This depends on the style that you shoot. This is very important to consider when you are buying a bow, getting it set up, or even making a bow. The standard method today, is split-finger. As you saw before, the split-finger method is slightly higher than the centre of the bow where the grip is. If you shoot three under, it’s closer to the centreline of the bow and if you stringwalk, that will be even lower and lower. Depending upon how far you go down. What this means, is if you shoot three under or stringwalk, you won’t need a positive tiller. You can use a neutral tiller or even a negative tiller. Depending upon how far down you go and how much tension you place on the bottom limb. So, what are the ramifications of not having the right tiller? Well, the first and most noticeable one, is vibration. Because the limbs don’t snap back at the same, time you will find there is excessive vibration in your bow. Secondly, the balance might feel wrong. This is because you expect the bow to have an even amount of resistance. But, if your tiller is wrong and you will notice this especially if it is the wrong way round. That the bow might be pulled up or down, when you reach full draw. Because, instead of having a compensated balance because of the tiller, you might be having too much tension on one limb, so you might be pulled down. Or, you might be pulled up. As you get to full draw, the limbs come under tension and things don’t feel quite right. Thirdly, it can effect the flight of the arrow. Because the limbs now come into place at different timings, it will push the arrow up, or down, rather than keeping it level. Some of these problems can actually be well managed. Especially if you shoot modern Olympic freestyle. For example, the issue of imbalance caused by improper tiller, can be mitigated by the use of stabilisers. So, in fact when you tune your bow and you try to get a good feel for the right balance between the limbs. Then the stabilisers will affect that. The issue of the arrow flight being affected by being pushed up or down, is actually a direct comparison to the nocking point. So, if you can’t adjust your tiller, you can adjust your nocking point. You can move your nocking point up or down to compensate for the arrow coming out incorrectly. This can also introduce other problems. If you are shooting a modern recurve, with tiller bolts that can be adjusted, you have to remember to maintain your tiller. So, if you are adjusting your tiller bolts, to change your draw weight, you have to make sure you give each one equal turns. If you want to turn it up, then make sure it is one full turn, one full turn. Or half turn, half turn. If you forget to do that and you have different rotations then the tiller will change. Also keep this in mind when taking the bow down, you might notice that the tiller bolts might be loose or you haven’t screwed them on properly. That means between sessions, your tiller will change. This can be, one of those really frustrating things that can completely ruin your score. You are shooting really well one week then the following week, nothing works right and that’s actually one of the causes. So, do keep in mind tiller bolts must be tightened and if you are changing your draw weight, make sure both tiller bolts are rotated the same number of times. For a traditional bow, you can’t change the tiller. It just comes the way it is. So when you buy the bow, you have to consider what tiller you need, for the style that you shoot. Otherwise, you may have to adapt your shooting style, for the bow that you get. This is also a problem, when you are making a bow. So, if you are making a custom bow, or you are ordering a custom bow, you do have to pass the information on. Do you tend to shoot split-finger? Three under? Stringwalk and so on. So that way, the bowyer, can make the right tiller adjustments. This can be done by making one limb stronger than the other. Or even using a shorter limb on one end. In summary, if you are a split-finger shooter, then you generally should be using a positive tiller and this is when the bottom limb is slightly heavier than the top limb. This can be measured by the difference between the limb and the string. The bottom string and the bottom limb, should be slightly closer than the top limb and string. and this difference is typically 1/4 inch to 1/8 inch. If you are shooting three under, or you stringwalk the you don’t really need a positive tiller. You might be better off with a neutral tiller. Is getting tiller right, super important? Not really. Most people can get away with having a neutral tiller or a positive tiller and the bow will function fine. But if you are getting to the intermediate, to advanced competition levels. You really should pay attention to what your tiller is. As part of your tuning. This can be a cause of your groupings not being as good as what they could be. Additionally, the argument can be made, especially for modern materials and modern recurves, that the technology and the materials are advanced to a point where they are fast, efficient and consistent. So, a slight mismatch in tiller, won’t make that much of a difference. The limbs already come together so quickly, that it won’t affect the shot that much. Hopefully that answers most questions about bow tiller. It’s not a very complex concept, but it can be illogical if you don’t think about it the right way. Anyway, this is NUSensei. Thanks for watching, I’ll see you next time.

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  1. I swapped my limbs on my Sage, top limb w/ bottom, 35lb limbs and noticed it shot no differently. I was adjusting for a slight twist in the light draw bow. I swapped them back however. I will check it out again. I bought a PSE 50lb recurve and the previous owner had limbs backwards lol oops for him. Peace

    great work on ur videos bro

  2. hi nu sence .
    that first bow . the one piece .
    is that a chek mate ??
    I thought the logo sticker looked like the chek mate one but it's at an angle and of course you are. moving it

  3. very good video, just one correction, you cannot string walk with split-finger (saying three under or string walk does not make sense in this case :-)). you can gap with three under (I shoot that way) or split-finger.

  4. It would be nice if I manage to find the actual mathematical formula for computing the proper positive tiller in relation to the distance between the arrow rest and the center of the bow.

  5. I think this is a really first rate video.  You covered a confusing topic with clear, concise, and thorough explanations.

  6. So, when I draw my bow, I use one finger above and two under. However when I'm at full draw I release the bottom finger, so Im holding with 2 fingers. Should I correct this when I move to recurve and will it cause problems?

  7. Bravo NUSensei.Again your video is right on time for me. Questions: I shoot 3 under. Where should I tie my nocking points? 2) Rule of thumb for increasing the poundage of my (barebow) recurve by turning the tiller bolts? 3) Is there a way to tie nocking points so that they are adjustable until you find the "right" spot to tie them? I'm a newbie pretty much alone in a community of compound shooters and big box stores who don't cater to Olympic style recurve shooters like me. Thanks.

  8. What do you think about "Loctite for nuts and bolts" being used on the tiller? 🙂
    You mentioned that some people have ones that loosen.

  9. Really nice video! Finally I'm getting closer to what I'm searching for a while: I'm into instinctive shooting but still like the high tech aspect of archery. So I finally decided to go for an olympic recurve, but bareboned. I'm shooting three under, so what kind of tiller would you recommend? I guess I can estimate a neutral or slightly negative tiller by imagining the center of force in my hand, right? Thanks and enjoy.

  10. I will have to respectfully disagree with you, Nu Sensei. This will be pretty long winded, but please bear with me.

    This will be explained based on the notion that the manufacturers have somehow decided to make the upper and lower limbs the same. It's probably an economic decision.

    You mentioned that in the case of a split finger, a positive tiller is called for because by drawing above the center, the top limb is closer to you than the bottom limb. That is in fact a false sense. In this case you have taken the perspective of your being a datum of measurement from your face. In the event that you were an alien with your head below your shoulders and your draw to anchor to the top of your head, the bottom limb would be closer to you. This evaluation of "closeness" is irrelevant from the standpoint of the bow itself, and therefore fails to explain why a positive tiller is required.

    The real reason for a positive tiller is as what you have broadly defined, a sort of "cam timing" analogous to compound. The real question in this case is why it has to be positive. Based on the compound analogy, I will now further expand on their similarities. When dealing with a two cam system, it is imperative that they achieve some sort of synchronous action. This synchronous action also demands that they bow start off the same i.e. at the same "gearing". Imagine two cars starting from zero to 60MPH, with one car on the first gear, and the other on a second gear. In most normal cases, the car that starts off on the first gear will achieve 60MPH in the shorter time, within a shorter distance.

    A two cam compound system is in fact an infinite series of gear deployment, evident from the varying lever ratio between the load (perpendicular string to axel distance) and the effort (perpendicular cable to axel distance), through the shot sequence. It can be adequately described as beginning from a low gear (higher cable distance than string distance from the axel) and gradually building up to a high gear (higher string distance than cable distance from the axel) in the case of a low let off cam, such as the Hoyt Spiral cams, giving it the superior speed performances when compared to other classes of higher let off cams. When you look at a recurve at full draw, it mimics this low to high gear characteristic, by having the outer tips retract to their rest positions first, leaving the inner portions either stationary, or outright in reverse motion near the limb butt. As the shot progresses, this retraction begins to build in terms of a larger proportion of the outer parts of the limb having a forward motion, with the tension of the string mostly remaining constant, similar to the situation of a high gear motion. It is this incremental increase in "gear" that provides the recurve bow with the high speeds achieved. At this point most of you would have lost me but let me continue in the next paragraph.

    When you turn the lower limb bolts into the riser to increase the positive tiller, you are not making the lower limb experience a stronger loading than the upper limb. It is in fact the opposite. The upper limb becomes more loaded. Since both limbs share the same string, they should be at the same tension, but that is only true when you talk about the string. If at this point you have completely lost me, think about fishing. When you leverage harder on the lower "rod", the fish on the upper limb fighting with the string is now yielding more to the increase in the effort used on the lower "rod". Now bring this all the way to the extreme and increase the tension until the string contacts the lower limb. See the picture?

    What positive tiller does, is to establish a common starting point in terms of gear ratio AT FULL DRAW. The reason it has to be positive, has everything to do with the main pressure point of the hand on the bow, being NOT AT THE GRIP THROAT, but at the lower portion, where the radius of the bow arm directs its force forward through the base of the thumb. This point is below the center of the riser, with the nocking point being above the center of the string, forming a downward tilting bow expanding vector. The lower limb in fact experiences a higher transition than the upper limb from brace to full draw, if one were to trace the paths taken by the two limb and compare them, because the bow arm is pushing the lower part of the bow. Limb loading during the draw is heavily affected by receding dead zones on the limbs, dead zones being the portion of the limbs still in contact with the string, in theory rendering that portion "unused". Having the lower limb set with a larger dead zone than the upper limb (in the case of positive tiller settings) ensures that by the time full draw is achieved, both upper and lower limbs are at equal footing. One interesting extrapolation of this theory predicts the increase in positive tiller settings for folks with larger hands, all else being equal.

    And that's the reason why you have positive tiller settings. Thank you all for kind your attention. Please don't attack me, I'm just a bored fat asian dude.

  11. Is it possible to change the tiller on an inexpensive take down, such as a Samick Sage, by shimming the limbs in the pocket?

  12. This explains a very odd looking long bow my great grand father had. There was an obvious difference. I had no idea what the deal was. Edit: It might not have been a long bow, but as a kid… it was pretty long! 🙂

  13. YOU'VE DONE IT AGAIN! I've watched a number of other videos that try to explain Tiller and you are the only one that really explains it PROPERLY. Many thanks NUSensei, your words of wisdom are a constant help to an aspiring archer like me 😉

  14. What about compound bows? On my bow, the limbs are exactly equally far away from the string. But the D loop is 125 mm closer to the top cam than to the bottom cam. The limbs are exactly equally long and look identical. The cams look identical, too. Why is this?

  15. I'm attempting to make my own recurve bow, i've never shooted one, but i love the crafting process, and I also find archery very interesting so i'll give it a try
    The point is that I dont know how it will come out, but I undesrtand that I should shoot in a way or another depending on the tillering I get, right?
    Since I'll be doing my own limbs too, out of fiberglass, they may not have the same draw weight so I'll put the stiffer dow

  16. Best video on tiller out there! Thank you for sharing your knowledge. Only comment measuring a one piece bow from the point it starts to curve is a hard location to find in any repeatable way.  Most measure where the material of the riser break out ends because its easier to locate.  Where the riser material is razor thin for some distance I find where it is a specific minimum thickness like 2 mm and just use that spot to measure.

  17. So on compounds tiller is "non-existant"? Meaning the "cam timing" is the equivalent to "tiller" on recurves and longbows?

  18. My Sensei I have a question about when carrying a bow strung up and ready for use in the woods for target and or bow hunting with a compound , recurve and long bow. How do you carry a bow when going into a wooded area along with quiver and target bag? Is it how Legolas does it?

  19. I don’t get it (no surprise, am not an archer). Why not design the bow with the nock point and ‘shelf’ where the arrow rests at the center, and the grip below. Seems like that would simplify things a great deal.

  20. please help me . . . . . . . . . "assume" One uses 2-under, 1-above DRAW with a Finger-Tab. Assume One always re-adjusts String's Nok-set to same position on string w.r.t. Rest (for Nocking Arrow to string, same way). Assume default TILLER was set to Bottom-limb=7.0625" & Top-limb=7.375". . . . . . . . . . Now please help with what happens NEXT ….. if TILLER is CHANGED to Bottom-limb=6.875" & Top-limb=8.000" , will the Arrow arrive on the target higher up the face, or lower down on the face???? Also, if TILLER is CHANGED to Bottom-limb=7.5" & Top-limb=7.125" , will the Arrow arrive on the target opposite way to first [changing to EXTREME positive tiller] example {using the slight/minor Negative tiller}????

    What does practical science demonstrate happens to arrow trajectory ????

    Please help me ? ?

  21. Thank You Thank You Thank You… Please teach and share the YouTuber "Shoreshot Archery" How to verbally present clear and clean information without personal fluffy opinions. He tries to be cute in digression and maudlin verbiage that only confuses listeners in search of didactic information.

  22. YOU DESCRIBED THE REASONS FOR A CERTAIN TUNINGS IN TILLERING BUT YOU FAIL, FAIL, FAILED TO SIMPLY STATE "HOW TO GET AN EVEN TILLER BY SCREWING THE BOTTOM LIMB BOLT "IN" OR"OUT" TO GET AN EVEN TILLER….

    SO "HOW" DO YOU "ADJUST" THE BOTTOM LIMB (WHICH IS 1/2" CLOSER TO THE RISER) 

    DO I SCREW THE LIMB BOLT IN OR OUT TO GET AN EVEN TILLER? SO IF MY BRACE HEIGHT IS 9.25" AND MY TOP TILLER OR LIMB MEASURES 8"; AND THE BOTTOM MEASURE IS 7.5" CURRENTLY …
     
    DO I SCREW THE BOLT "IN" OR OUT TO GET THE BOTTOM LIMB TO BE 8" LIKE THE TOP LIMB???

  23. I shot the string walking technic. which kind of tiller i must have
    up 17 down 16.7 or up 17 down 17.3 or the same 17 and 17.

  24. thank you I'm looking at the tiller now as a way to make my bow shoot better. And I have been moving my knock point around to find where it feels best and as you say this is one way to balance out your draw weight I'll leave it with that. Now all that said I find that each time I set up new arrows I have to change or feel I need to change the knock point. Does this sound correct to you or am I perhaps a bit mental.

  25. That was outstanding!! Thank you for making it so understandable! You took care to give detailed information and make it readily understandable. I am NOT a competitive archer. I have been using a Fred bear recurve bow for 48 years and never bothered to worry about tiller. I used it for hunting and always hit what I aimed at. Then again, I always practiced frequently. The reason I am interested in tillering now is because I am retired and I am going to be building bows of my own. Your video is the best one I have heard on this subject. Best of luck to you in your competitions. Thank you.

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