Weak upper limb.

Test it. Set your tiller to zero, then flip your limbs and if you see a negative tiller, then that should confirm it.

If not, then I don't know.

 

Negative tiller setup is quite common tuning BB 3 under . Some archers for instance simply reverse the limbs if they have a pair with built in positive tiller.

The rule of thumb (for symmetric bows) tends to remain the same similar to recurve olympic one, just reversed:

- Recurve Olympic---> Zero to limbs positive natural tiller
- Bare Bow 3 under ---> Zero to limbs negative natural tiller (limbs reversed)

Of course you can play with tiller bolts to get the negative tiller you need, but for sure better to start from limbs already in negative tiller with bolts even.

Tiller tuning is not very imporant in recurve, as you can get same results easier changing balance of stabilizers. For Bare bow, weights options are limited, so tiller tuning (= changing riser vertical position at full draw) becomes more relevant.

 

Vittorio, in this case, would three under refer to the arrow sitting just on the index finger, or with a gap so that the eye is just next to the arrow?

 

Referring to WA rules only (I'm not very familiar with IFAA and IBO rules),
- 3 under must be used touching the arrow (with index finger) for Long Bow division
- 3 under can be in any position on the string (=stringwalking) for Bare Bow division, that means that keeping anchor point constant, arrow can be in any position over it depending the distange you have to shoot
- 3 under can be in any position on the string for Recurve -Olympic shooting, but in practical cases, index is ever touching the arrow

 

Tiller tuning is not very imporant in recurve, as you can get same results easier changing balance of stabilizers. For Bare bow, weights options are limited, so tiller tuning (= changing riser vertical position at full draw) becomes more relevant.

Very good point Vittorio: tiller tuning changes vertical position of the riser.
Also depends on the riser, different risers "like" different tiller.
JMHO
Martin

 

It is important to understand that the only real way to change speed of one limb in relationshiop to the other is to file one of the two limbs more, like boyers are doing making limbs pairs or one piece bows. If you simply load or unload more one limb in relationship to the other, you are only changing the angles of the limbs to the risers and between each other, so altering also how string will touch them (different then one to the other). Or, reversing the equation, altering the position of the riser in relationship to the verticality of the bow system.
When you draw the bow starting form any contdition, 3 other factores come to play:
1) stabilizers and weights distribution (simple to adjust)
2) nocking point ( simple to adjust)
3) pressur point on the grip (difficult to adjust)

Unfortunately for archers, the 5 parameters are interrelated and you may easily come to an infinite loop trying to tune your system in your shooting style.

When you say that "different risers like different tiller" you ar not talking about risers, but about a full system were "riser" word should be replaced by "grip", and only if if you keep all other parmeters fixed and you want to tune by tiller bolts pre-load, only.

Ages ago I have eliminitated tiller tuning from my process, defining zero tiller as the solution good for almost all bows, and limited changes of pressure points on the grip by the development of the Ball grip. As natural tiller in a pair of limbs can't be changed, this reduces the tuning to 2 parmeters only: distribution of weights and nocking point. Much simpler, faster and effective 99% of times in recurve-olympic style tuning.

Bare Bow stringwalking generates quite different balance of the forces to the grip and to the limbs, and of course also changes the angle of the riser in realtionship to the positon of the hand on the string, so changing a lot the reaction at the release at different positions. So, sometime altering the riser angle (altering tiller bolts relationship) ) may help a bit more than in Recurve-Olympic, if you don't want to add a lot of weigh to the bottom part of your riser (a lot means >> 1kg). But, you go in this case back to minimum 3 inerrelated parameters in tuning, and tuning process may become endless....

 

So, I'm very confused by the terminology here. Maybe.

Positive tiller is when the tiller on the top limb is greater (longer) than tiller on the bottom limb.

Negative tiller is when the tiller on the bottom limb is greater (longer) than tiller on the top limb.

Correct?

 

That is the way I always measured and set tiller.

I am surprised that no one has replied to your post either stating right or wrong.

Vittorio is this correct?

 

Great post as usual Vittorio.
A very good point about the grip. That’s why I have been using the same grip (Jager BEST) for more than 10 years on each and every riser.
For riser I mean riser design because different risers have different location for the pivot point, different pivot point to rest distance, etc.
Of course then you have different position of the grip on the string…..
Thank you very much
Martin

 

Ages ago I have eliminitated tiller tuning from my process, defining zero tiller as the solution good for almost all bows

Much simpler, faster and effective 99% of times in recurve-olympic style tuning.

Same conclusion I came to years ago.

 

"Negative tiller setup is quite common tuning BB 3 under . Some archers for instance simply reverse the limbs if they have a pair with built in positive tiller. "

Do modern ILF limbs come with built-in tiller?

Thanks,
Greg

 

From day to day observations, most manufacturers seemed to have done away with that, evident from most mistakenly setup bows with inverted upper/lower limbs having little to no observable score variations when shooting in competitions (sometimes during training while scores are taken).

I'm not involved (well, not really) in design and manufacturing but I do see that it makes economic sense to make all the limbs for a particular model and poundage without differentiation of upper and lower limbs.

 

I've never played around with tiller. What does it do for barebow as a tuning variable?

I play with nocking height, brace height, and tip weight, centershot, plunger tension.

 

Great question. I run even tiller, and all I adjust is nocking height, brace height, tip weight, centershot, and plunger tension.