I was told at a club comp yesterday that the tiller was set up wrong on my barebow. The limb tips were oscillating heaps and a couple of recurve experts said they were working against each other and vibrating way too much. I have a Bernardini Nilo riser with factory settings, with a tiller of about 1/8" on the top limb. I was told to stiffen up the lower limb till the limb tip oscillation reduced. They suggested a turn out on the top and one in on the bottom limb till limbs settled down. I tried this, and ended up with a 1 1/8" difference in tiller before the limbs seemed to stabilise. This seemed enormous too me but I've been assured that it's correct for my set up. Is there any barebower experts out there who know how to set up barebow for 3under release? Thankyou

An interesting problem. I can't resist asking how you knew when the limbs were landing together. This sort of question does crop up now and again, so if the method is to try a little change at a time, which seems to make sense; then how does an archer know when it is correct?

Zero tiller is common amongst us barebowers, especially string walkers. I suggest you have a look on the tradtalk forum where you will find advice from some of the worlds best barebow archers. Traditional Archery bowhunting selfbows recurves longbows 3D Field Archery

Originally Posted by geoffretired

An interesting problem. I can't resist asking how you knew when the limbs were landing together. This sort of question does crop up now and again, so if the method is to try a little change at a time, which seems to make sense; then how does an archer know when it is correct?

They were filming the movement of the tips on a mobile phone. I kept adjusting the limbs till the vibration and oscillation seemed to cut back according to the observers and film crew. I thought about this when I got home though, and decided that I didn't like it. It just seems too much to me, and drawing in the back garden the bottom limb just felt too heavy, so much so that it seemed harder to pull. I had a rethink, and decided to back the bottom limb off, and play around with the brace height. I ended up with 1/2" tiller, and a much bigger brace height. This also seemed to cut back the oscillations, tho I can see the bottom limb is now oscillating more than the top. I have a feeling that more is in play here than was first suggested, and maybe part of the problem is that the limbs are too long for my draw length?

MMMm I wonder if the video was fast enough to show the detail of the arrivals.
Border Bows tells us that limb return is like a race between two runners. One is stronger and faster than the other. The stronger, faster one has a longer distance to travel than the other, so if the extra distance is right, it will catch up just by the end of the race.So, if the draw length is right, they end together. If the draw length is a bit short, perhaps lowering the BH will give a bit more distance in which to catch up. Raising the nocking point changes the distance between the two at the start.So that can be used to get things where we want them.

Originally Posted by Job

They were filming the movement of the tips on a mobile phone.

Real bad plan, the light detecting sensor in most digital video capturing devices work like as if you where reading a page of text reading accross and progressing down so by the time the bottom of the image has been captured any rapid movement will show a slight delay between bottom and top when viewed.

Originally Posted by geoffretired

MMMm I wonder if the video was fast enough to show the detail of the arrivals.
Border Bows tells us that limb return is like a race between two runners. One is stronger and faster than the other. The stronger, faster one has a longer distance to travel than the other, so if the extra distance is right, it will catch up just by the end of the race.So, if the draw length is right, they end together. If the draw length is a bit short, perhaps lowering the BH will give a bit more distance in which to catch up. Raising the nocking point changes the distance between the two at the start.So that can be used to get things where we want them.

Don't forget if the riser end rotates (towards the stronger runner) then the relative distances to the finishing lines change
Also remember that both limbs always bottom out simultaneously as this is defined by the string which connects both limb tips.

What's different is the relative energy between the two limbs when they bottom out. Hold a riser firmly and push down on one limb tip. Both limbs are stationary but have different energy content & not in equilibrium. Let go the limb tips and the limbs oscillate.

Cheers Joe,I get that.heehee.
I guess that the riser rotating towards one limb or the other, will repeat unless the archer changes the stabilaer ettings, or changes the way he/she shoots the shot.

After making changes to your tiller don't forget to check your nocking point height on the string - its all interelated

Originally Posted by buzz lite beer

Real bad plan, the light detecting sensor in most digital video capturing devices work like as if you where reading a page of text reading accross and progressing down so by the time the bottom of the image has been captured any rapid movement will show a slight delay between bottom and top when viewed.

You should look at an image of the string during release when taken with a digi camera, it can look longer than the bow, very weird!

Originally Posted by joetapley

Don't forget if the riser end rotates (towards the stronger runner) then the relative distances to the finishing lines change
Also remember that both limbs always bottom out simultaneously as this is defined by the string which connects both limb tips.

What's different is the relative energy between the two limbs when they bottom out. Hold a riser firmly and push down on one limb tip. Both limbs are stationary but have different energy content & not in equilibrium. Let go the limb tips and the limbs oscillate.

I think I get what you're saying, that you need to tiller both limbs so that their energy output is the same. I presume this is the principle used by the Japanese when designing their yumis, which have a serious difference in limb length? I would think there would be some mathematical formula that could be used to give the required tiller on each? Or not?

Originally Posted by buzz lite beer

Real bad plan, the light detecting sensor in most digital video capturing devices work like as if you where reading a page of text reading accross and progressing down so by the time the bottom of the image has been captured any rapid movement will show a slight delay between bottom and top when viewed.

I have come to the conclusion that the 'experts' down my club don't know what they are talking about. I have gone to zero tiller and a much higher brace height and the prob seems to be cured, almost.

Originally Posted by chrispy

Zero tiller is common amongst us barebowers, especially string walkers. I suggest you have a look on the tradtalk forum where you will find advice from some of the worlds best barebow archers. Traditional Archery bowhunting selfbows recurves longbows 3D Field Archery

Took your advice, followed the DAS recommends, and almost sorted. I think 90% of the original problem was having overlong limbs for my draw length (again a recommend by a club member) and a much too low brace height. Gone to zero tiller now and maximum brace and the top limb is completely still. Some vibes on the bottom but I can live with that. Thanks again

I think I get what you're saying, that you need to tiller both limbs so that their energy output is the same. I presume this is the principle used by the Japanese when designing their yumis, which have a serious difference in limb length? I would think there would be some mathematical formula that could be used to give the required tiller on each? Or not?

Interesting ideas Job,
What I have been picking up from Border Bows is that the bottom limb, if left as a perfect copy of the top one,would be bent more during the draw.Having further to travel to get back, it would arrive later than the top one. So, the bottom limb can be made a little stiffer than the top one. Now, it still bends more than the top one, but not so much, so it has slightly further to travel, but being stronger/faster, it will catch up if it is given the right amount to distance to catch up in. If that is correct, I guess the bottom limb gives a greater output than the top one. I can only guess that it might be about what energy is left in each limb by the time the string goes tight.( as Joe said earlier)
How that happens, and/or what the positions of the limbs is like at that point in time, I need help understanding.