Paper Tune Root-Cause Diagnostic
A tear tells you the arrow left the bow with some yaw. It doesn’t tell you why. Answer what actually happens when you test it and this ranks the real suspects — nock pinch, center shot, cam lean, spine — before you spend an afternoon moving a rest that was never the problem.
ArcheryEra's calculators are built and maintained by a mechanical engineer with 8+ years of archery-domain experience. Models, assumptions and limitations are shown, not hidden.
Want to see the exact scoring weights behind this ranking? Read our Methodology & Assumptions →
Simulation Lab
Test it, don’t just read the tear
Nine quick answers — your tear, what happened after a few small rest moves, and three checks that cost nothing — turned into a ranked list of what to fix, in order.
Pre-Sets
Five real diagnostic patterns, loaded as a whole answer set at once. Pick the one closest to your situation, then correct anything that doesn’t match — everything stays editable.
Pick one to load a whole answer set, then change anything from there.
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Join r/ArcheryEra →What the paper said
Shoot through paper at 6–8 ft with a field point. Use three arrows and trust the tear that repeats.
What happened after a few small rest / nocking-point moves
Move 1/32 in at a time, three field points at 30+ yards each time. This single answer separates the rest-fixable causes from everything else.
Three free checks — no gear, no rest moves
Spin the shaft with the head on, dust the vanes and rest with foot powder, and shoot a few with a dead-relaxed hand. All three take a few minutes and rule out what a rest can never fix.
Your setup
No tear to diagnose
A clean tear means the arrow left the bow lined up. If your groups still aren’t where you expect, the Broadhead Flight & Tuning Stability Checker covers what a fixed-blade head does to a tune that paper can’t see, and the How to Paper Tune a Bow guide covers re-checking at a longer distance.
Ranked suspects, from your answers
⚠ The tear got worse after your rest moves — that usually means the direction was wrong, not the theory. Try the opposite direction in the same small steps before trusting this ranking's rest-fixable causes.
Fix in this order
Spine flagged as a suspect
Run your real draw weight, draw length, point weight and cut length through the Dynamic Spine & Shaft Flex Calculator before buying a different shaft.
Once the tear is clean
A clean tear on field points doesn’t mean broadheads will group with them — the Broadhead Flight & Tuning Stability Checker shows how much steering margin your fletching has against the head you actually hunt with.
Guide
Diagnosing a Paper Tune Tear: A Step-by-Step Workflow
Most paper-tuning advice stops at "chase the tear with the rest." That works when the rest is actually the problem. When it isn't, you can spend an entire range session moving something that was never going to fix it. Here's the order that actually separates the causes.
Step 1: Rule Out What a Rest Position Can Never Fix
Before moving anything, run three checks that cost nothing. Spin the arrow — head on — on a spinner or across two field points seated in a scrap of 2×4, and watch the tip against a fixed mark; a tip that traces a circle is a bent shaft or a crooked insert, and shooters comparing notes on ArcheryTalk routinely find one or two arrows in a dozen doing this. Dust the vanes and rest with foot powder or lipstick and shoot one arrow — a clean wipe across a launcher arm or cable makes a tear no rest position will close. Shoot a few arrows with a completely relaxed hand and a wrist sling — if the tear changes, grip torque was steering the bow, not a tuning error.
Step 2: Read the Plane, Not Just the Direction
A horizontal tear (tail left or right) and a vertical tear (nock high or low) point at different short lists of causes. Horizontal tears cluster around center shot, cam lean on a compound, and grip torque. Vertical tears cluster around nocking point height and nock pinch — the string groove gripping the nock too hard and kicking the tail off-line at release. Both lists overlap with the mechanical checks in Step 1, which is exactly why those come first.
Step 3: Test the Rest, Don’t Just Read the Tear
Move the rest or nocking point in small steps — 1/32 in at a time — and shoot three field points at 30 yards or more after each move; 20 yards is too close to show a real gap. What happens next is the single most useful piece of information in this whole process: a tear that closes cleanly within a few small moves is very likely center shot or nocking point height. A tear that barely shrinks, or doesn’t move at all after several correctly-directed moves, is pointing somewhere the rest can’t reach.
How Do I Know If It's Cam Lean and Not Center Shot?
Both produce a horizontal tear, which is why this is one of the most argued-about calls in tuning threads — the Rokslide community has picked this apart at length. The tell is the same rest-travel test from Step 3: center shot responds within normal rest adjustment, while cam lean keeps producing a tear even after the rest has run out of reasonable travel, because the string itself is tracking off to one side at the cam. That calls for a draw board and a look at cam timing, not another 1/32 in of rest movement, and Bow International's technical breakdown of cam lean covers what a shop checks for.
Common Pitfalls & Community Solutions
- Chasing the rest when the nock is the problem. A nock seated too tight on the string produces a vertical tear that looks exactly like a nocking-point error. Archers in a long ArcheryTalk thread on a stubborn nock-low tear eventually traced it to nock fit, not nocking point, after multiple rounds of rest adjustment did nothing.
- Reading a horizontal tear as spine without testing it first. Spine is a real possibility, but it's the last suspect to check, not the first — test the mechanical causes and the rest-move result before buying a different shaft.
- Changing two things between paper checks. Move one variable, shoot paper, read it, then decide the next move. Adjusting the rest and the nocking point in the same session makes it impossible to know which change did what.
- Giving up after one rest move. Threads on nock-high tears show the pattern repeatedly: a single move rarely tells the whole story, but two or three in the same direction usually do.
Frequently Asked Questions
What actually causes a paper tear, beyond "my bow isn't tuned"?
A tear is the arrow leaving the bow with some yaw between the nock end and the point end. What puts that yaw there varies — nock pinch, center shot, nocking point height, cam lean, grip torque, contact with a cable or launcher arm, a bent shaft or crooked insert, or a spine mismatch. The tear only confirms yaw exists; it doesn't say which of those caused it.
Does cam lean really cause a paper tear on a compound bow?
Yes — it produces a horizontal tear that looks identical to a center-shot problem, and the way to tell them apart is whether the tear responds within normal rest travel (center shot) or keeps producing a tear even after the rest has run out of reasonable adjustment (cam lean, which needs a draw board and a timing check instead).
What should I do once I have a primary suspect?
Fix it, then shoot paper again before changing anything else. One variable at a time is what makes the next paper check mean something. If spine comes back as a suspect, check it against a manufacturer chart with your real numbers before buying shafts.
Under the hood
How far can you trust this ranking?
This isn’t a physics simulation — it’s a transparent, rule-based scoring system. Each answer adds points to the causes it's real diagnostic evidence for, using weights set from how strongly each signal actually rules a cause in or out (a mechanical defect from a wobbling spin test outweighs a tear direction alone, for example). Treat the ranking as a place to start testing, not a verdict — the free checks and the rest-move result are worth more than the tear direction by itself, and the tool says so in how it weights them.
How each score is worked out Nine inputs, eight candidate causes — tap any one for the exact points
Why the free checks are worth more than the tear direction Direct evidence beats an inference, every time
A wobbling spin test, a mark from the powder check, or a tear that changes with a relaxed grip are all direct evidence — you watched the cause happen. Tear direction, by contrast, is an inference: it narrows the field to a short list of usual suspects, but several different causes can produce the same-looking tear.
That's why a wobbling spin test adds 55 points straight to "mechanical," a contact mark adds 65 to "contact," and an improving grip test adds 55 to "grip torque" — each large enough to dominate the ranking on its own — while tear direction alone contributes a baseline of 30 points, scaled by tear size (×0.7 small, ×1.0 medium, ×1.3 large), split between the plane-appropriate causes.
One more direct-evidence check works the same way: if the tear looks different from arrow to arrow rather than repeating, that adds 35 points to "mechanical" on its own — a tear that won't repeat can't be a steady tuning problem like center shot or spine, since those produce the same tear every time. It's evidence of something inconsistent between arrows instead, like a bent shaft in the mix or an inconsistent release.
Why the rest-move result carries the most weight of all It's the one input that's actually a test, not an observation
Everything else in this tool is something you observed. The rest-move result is something you tested — you made a change and watched what happened, which is the strongest kind of diagnostic evidence available without a shop visit.
- Closed up clean → +45 to the plane-matching cause (center shot for horizontal, nocking point height for vertical), and spine drops toward zero.
- Shrank, won’t fully close → +20 to the plane-matching cause, +18 to spine, +12 to cam lean if the bow is a compound with a horizontal tear.
- Didn’t change at all → +40 to spine, +30 to cam lean (compound, horizontal only), +10 to mechanical — this is the strongest single signal that the rest was never the problem.
- Got worse → a smaller +10 to the plane-matching cause, +15 to spine, and a warning flag — getting worse after a correctly-labeled move usually means the direction convention was backwards for this bow, not that the theory is wrong. See the FAQ on the disagreement between the paper-tune and broadhead-tune conventions.
Nock fit — the check most tuning advice skips A tight nock produces a tear that looks exactly like a nocking-point error
A tight nock adds 25 points to nock pinch outright, plus a further 12–35 points (scaled by tear size) if the tear is vertical, since pinch shows up almost exclusively as a nock-high or nock-low tear. A loose nock adds a smaller 8 points to nock pinch and 5 to mechanical, since an inconsistent fit can also contribute to an inconsistent release without being true pinch.
Why cam lean only scores on a compound bow Recurves and longbows don't have a cam to lean
Cam lean is a compound-bow-specific failure mode — a recurve or longbow has no cam to come out of time, so this cause is locked to zero unless the bow type is set to compound. When it is, a horizontal tear adds 15 points to cam lean at the baseline stage, and a further 12–30 points depending on the rest-move result, since cam lean is exactly the kind of cause a rest move can't fix — which the "didn't change at all" answer captures directly.
How the bands are drawn — Primary Suspect, Worth Checking, Unlikely Round numbers, chosen to be honest about how blunt this instrument is
Every cause's score is clamped to 0–100. A score of 45 or higher is shown as a Primary Suspect. 20–44 is Worth Checking. Below 20 is treated as unlikely and shown faded in the ranking. These are round, deliberately conservative cutoffs, not a statistically fitted model — this tool takes no position stronger than "test this first," because a shop visit or your own paper tests are the only way to actually confirm a cause.
This is a rule-based diagnostic aid, not a substitute for a bow-press or draw-board inspection. If a cause ranked "unlikely" turns out to be the real one, trust your own testing over this page — and consider leaving a comment so the weights can be improved.
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If this ranked the wrong cause for your bow, that's the most useful thing you could leave here. Your answers, what actually fixed it, and the tear you started with beats an opinion every time — and corrections get the weights improved.