Tiller
Tiller is the difference between the string-to-limb-pocket distance on the top limb versus the bottom limb. Equal tiller means equal limb stress; positive tiller means the top limb sits farther from the string. Recurve archers commonly start with a slight positive tiller (around 1/8"–3/8"), then verify with paper tuning because unequal tiller directly affects nock travel.Detaily
Tiller is measured with a ruler or tiller gauge held against the string and measured perpendicular to it at the same reference point on each limb — typically where the limb meets the limb pocket or the upper edge of the limb bolt recess. The measurement is taken on both sides, and tiller is expressed as top tiller minus bottom tiller. A value of +1/4" means the top limb sits 1/4" farther from the string than the bottom limb. For recurve bows with adjustable limb bolts, tiller is one of the few measurements the archer controls directly by tightening or loosening the limb bolt on each limb independently.
Tiller affects the dynamic balance of the bow during the shot. When the limbs are under unequal stress, the bow tips slightly at the handle during the power stroke — the limb under more stress drives the riser in that direction. An unequal tiller can cause the arrow nock to travel on an arc rather than a straight vertical path, which shows up as inconsistent vertical grouping that persists even after nocking point and rest height have been confirmed. This nock-travel arc is the mechanical link between tiller and paper-tuning results.
For recurve bows, a commonly referenced starting point is a slight positive tiller — meaning the top limb is marginally farther from the string — because the arrow rest is positioned above the bow's geometric center of the handle. The exact value is bow- and archer-specific; archers with high draw weights or a pronounced grip angle may find a different tiller optimal. On most modern recurve limb systems, tiller is adjusted by turning the limb bolt half a turn at a time and re-measuring after each adjustment.
On compound bows, tiller is largely fixed by the limb pocket geometry and is not separately adjustable on most production bows. However, checking that top and bottom tiller measurements are equal to the manufacturer's spec is still a useful diagnostic when troubleshooting vertical grouping issues — a limb pocket that has shifted or a limb that is not seating correctly can produce an asymmetric tiller reading that needs a bow-press inspection rather than a field correction.
související v BowSmith
Časté otázky
- How do I measure tiller accurately without a dedicated gauge?
- A standard ruler works. Place it against the string and hold it perpendicular to the limb, measuring from the string to the same anatomical point on each limb — typically the top edge of the limb pocket or the base of the limb. Take three measurements per side and average them to reduce parallax error.
- My recurve groups are scattered vertically even after I set the nocking point correctly. Could tiller be the cause?
- Yes, this is a classic tiller-related symptom. Measure your top and bottom tiller and compare to your intended setting. A difference of more than 1/8" from your target tiller can produce nock-travel inconsistency that looks like a nocking point problem in paper but doesn't respond to nocking point adjustments.
- Does tiller need to be re-checked after changing limbs?
- Always. New limbs seat differently in the pocket and may have different stiffness characteristics that require a fresh tiller adjustment. Re-measure after installing new limbs, after any limb bolt loosening (shipping, transport), and at the start of each season.