Dialed.

The trust page

How this fitting is computed

Every recommendation on this site traces to an inspectable rule with a source. This page is the whole system, plainly: where the numbers come from, how the engine reasons, what the LLM is and isn’t allowed to do, and the pledge that keeps manufacturers away from results.

The pledge

Recommendations are computed from your numbers and our published methodology. No manufacturer can buy placement, supply demo gear, or pay for position. Advertising is confined to Learn articles and always labeled. No ad ever shares a page with a recommendation, and no advertiser sees your numbers. The fitting itself is funded by golfers unlocking their reports, never by the industry it evaluates.

The engine, in four layers

  1. L0 · Flight targets. Optimal launch and spin windows computed for your club speed and attack angle from published optimization data. Authorities do disagree: the 2010 Trackman optimizer wants more spin than modern MyGolfSpy windows. Where that happens, we encode the blend and the disagreement rather than false precision. Deliberately overlapping shaft-flex bands, speed-conditional descent-angle thresholds, and no compression-by-swing-speed ball myths.
  2. L1 · Fitting rules. 51 rules (release 0.15.0) map your numbers to findings and prescriptions. Each carries a rationale, a confidence level, and provenance. Every result shows which rules fired. Click “show the rule” on any recommendation.
  3. L2 · Product examples. A hand-curated database of gear classes with examples across price tiers, including used-market picks. Examples, never endorsements. No manufacturer supplies, reviews, or pays for placement. Seed data is marked unverified until each spec is checked against the maker’s page.
  4. L3 · Plain-English explanations. Result write-ups are composed from human-written templates bound to the engine’s output. A language model may later phrase them more personally. It will never be allowed to introduce a number, product, or claim the engine didn’t compute.

Determinism & versioning

The same numbers produce the same fitting, every time. Each session records the engine version (0.2.0) and knowledge release (0.15.0) that produced it. Knowledge changes ship as reviewed releases gated by a golden-test suite of expert-verified fittings. That makes “the fitter got smarter” an auditable changelog, not a vibe.

Sources

  • Driver optimization grid (club speed × attack angle → optimal launch/spin/carry, carry- and total-optimized)

    TrackMan Driver Optimization chart (2010), archived at wishongolf.com/wp-content/uploads/2012/07/TrackMan-Driver-Optimization_2010.pdf · TrackMan-produced document; predates current balls/heads, so treat it as shape-of-curve with tolerances rather than gospel

  • Simplified optimal driver launch/spin windows by speed band

    https://mygolfspy.com/news-opinion/instruction/optimal-launch-and-spin-chart-for-drivers-are-you-in-the-right-range/ · MyGolfSpy (2025), based on TrackMan data

  • PGA/LPGA tour averages per club (speed, launch, spin, height, land angle, carry)

    TrackMan tour-average tables; refresh noted at https://www.trackman.com/blog/golf/introducing-updated-tour-averages · TrackMan-published

  • Smash factor benchmarks (driver optimum ≈1.50; amateur averages by handicap; 7-iron ≈1.33 PGA)

    https://www.trackman.com/blog/golf/smash-factor · TrackMan-published

  • Spin axis definition and sign convention (+ tilts right = ball curves right; − left), the ±2° band that reads as a straight shot, and the single-digit playability boundary behind SPIN_AXIS.shapedDeg

    https://www.trackman.com/blog/golf/spin-axis · TrackMan-published parameter definition; the ±2° straight band is TrackMan's own and is independently stated by FlightScope (https://flightscope.com/pages/spin-axis). The 10° cut is practitioner judgment from a TrackMan University Master quoted on the same page ('I consider a single digit Spin Axis value to be a playable ball flight'), not a TrackMan measurement

  • Spin axis is the least reliable metric a launch monitor reports, which is why measured-shape rules require a minimum shot count

    https://www.mdpi.com/1424-8220/22/23/9069 · Villarrasa-Sapiña et al., Sensors 2022, 22(23), 9069, peer-reviewed. n=10 amateurs on a FlightScope Mevo+, test-retest: driver spin-axis ICC 0.13 with SEM 13.75° at seven shots. It was the worst of the fifteen parameters measured and never reached acceptable reliability up to fifteen shots. Small sample, indoor, players selected their own good shots

  • Iron descent-angle rule (~45° to hold greens) and its speed-conditional breakdown

    https://www.titleist.com/learning-lab/performance/golf-ball-angle-of-descent and https://www.foresightsports.com/blogs/golf-tips/how-to-optimize-iron-distance-based-on-swing-speed · Titleist Learning Lab; Foresight (practitioners note the rule breaks below ~85 mph 6-iron ball speed)

  • Driver shaft flex bands by club speed; sources disagree by 5–10 mph, so bands overlap deliberately

    https://golf.com/instruction/shaft-flex-you-should-play-based-on-swing-speed/ (True Spec) and https://mygolfspy.com/news-opinion/instruction/golf-driver-shaft-flex-chart-find-the-right-flex-for-your-swing-speed/ · True Spec via GOLF.com; MyGolfSpy. Both stress there is no industry standard

  • Compression-by-swing-speed ball fitting is a myth; fit spin/short-game first

    https://mygolfspy.com/news-opinion/golf-ball-compression-guide/ and Titleist green-to-tee philosophy · MyGolfSpy robot testing; Titleist fitting philosophy

  • Average male amateur driver baseline (93.4 mph, −1.6° AoA, 3275 rpm, 204 carry) and optimized-same-speed comparison

    https://blog.trackmangolf.jp/performance-of-the-average-male-amateur/ · TrackMan-published

  • Launch-monitor noise floor ~5 yd carry SD / ~6 yd lateral SD for a repeatable swing (two lenses converged on identical figures)

    https://www.trackman.com/blog/golf/how-to-utilize-the-consistency-number and launch-monitor patent US-8622845 · research:evidence-effect-sizes:C18, research:fitting-methodology:C5 · TrackMan consistency guidance + launch-monitor engineering data; adopted as the minimum-meaningful-delta gate

  • Driver loft lever: +1° loft ≈ +1° launch and +400–500 rpm spin (center strike, constant AoA)

    https://exactgolf.com/club-shaft-tests/how-does-driver-loft-influence-the-spin-generated/ and https://golfwrx.com/296951/how-adjusting-your-driver-loft-changes-your-ball-flight/ · research:evidence-effect-sizes:C1/C2, research:shafts-woods:C2 (independent convergence) · TrackMan-derived club testing, replicated across lenses

  • Altitude adds ~1.1–1.2% carry per 1,000 ft (a 2%/1,000 ft figure circulates but is internally inconsistent with its own yardage examples, so we encode the conservative range)

    https://www.titleist.com/learning-lab/performance/altitude-and-golf-ball-flight · research cross-conflicts.md #1 (vs research:ball-construction:C11) · Titleist R&D test, independently echoed by MyGolfSpy; reconciled range

  • Temperature costs ~2 yd carry per 10°F at driver, ~1.3 yd per 10°F at wedge; humidity is negligible (two lenses converged)

    https://golf.com/instruction/heat-altitude-affect-golf-ball-distance/ (Andrew Rice TrackMan testing) · research:ball-construction:C9, research:archetypes-special-cases:C17 · TrackMan-measured by a GOLF Top-100 teacher; USGA rule-of-thumb agrees

  • Adjustable hosel sleeves move real launch/spin windows (~600–800 rpm and ~2° launch across a driver sleeve's range) while co-varying face angle ~1.5–2° per 1° of loft on single-axis systems

    https://golf.com/gear/drivers/robotest-how-much-change-ball-flight-adjustable-driver/ · research:brand-systems:C12, research:heads-design:C14/C16 (convergent) · GOLF.com RoboTest (GCQuad robot) + OEM tuning guides; robot-verified windows

  • Forgiving driver heads retain ~5–8% more ball speed on heel/toe mishits than 'player' designs, with near-zero benefit on center strikes. Attribution corrected kb 0.8.0: this is a whole-head measurement, not the effect of the MOI figure alone, which accounts for roughly half a percent across the entire legal range

    https://www.golfdigest.com/story/2025-drivers-forgiveness-robotic-testing-insights · research:evidence-effect-sizes:C6, research:heads-design:C9 (measured retention only; yardage estimates excluded per completeness critique) · Golf Digest / Golf Laboratories robot testing

  • Ball model spin spreads by club: driver ~850 rpm, 7-iron ~1,300 rpm, greenside (35 yd) ~4,000 rpm, so ball fitting is greenside-first

    https://mygolfspy.com/buyers-guides/golf-balls/golf-ball-spin-range-lowest-versus-highest-in-2025-testing-driver-iron-wedge/ · research:ball-construction:C13, research:evidence-effect-sizes:C15 · MyGolfSpy robot testing

  • Low compression does not add distance at any speed: softest balls lost ~8/11/15 yd of carry at 78/93/114 mph in robot testing (the 'soft = longer for slow swings' claim is refuted)

    https://www.todays-golfer.com/news-and-events/equipment-news/stop-buying-soft-golf-balls/ · research:ball-construction:C6/C8, cross-conflicts.md #11 · Today's Golfer / independent robot test

  • Tour anchors for the long clubs, all columns: PGA 3W 107 mph/9.2°/3,655 rpm/30 yd height/43° land/243 yd carry; 5W 103/9.4°/4,350/31/47°/230; hybrid (15-18°) 100/10.2°/4,437/29/47°/225. LPGA 3W 90/11.2°/2,704/23/39°/195 (tee-weighted: its −0.9° AoA and spin are discontinuous with the 5W/7W rows); 5W 88/12.1°/4,501/26/43°/185; 7W 85/12.7°/4,693/25/46°/174

    https://teeituprva.com/wp-content/uploads/2019/03/PGA-AVERAGES-INTERACTIVE.pdf and LPGA-AVERAGES-INTERACTIVE.pdf · research:fairway-woods:C1/C2, research:hybrids:C1 · TrackMan-published tour sheets, verified by direct read of both PDFs 2026-08-13 (the hybrid row and the land-angle column exist on the primary source; the 2023/24 refresh dropped the column)

  • Second-vendor fairway anchors off the deck: Foresight slow band 3W 92 mph/10.3°/3,234 rpm/208 yd and 5W 90/11.6°/4,238/203; fast band 3W 107/8.0°/3,801/250 and 5W 103/8.8°/4,624/230; plus a 22° hybrid at 87 mph/12.9°/5,415/184

    https://help.foresightsports.com/hc/en-us/articles/47208228295187-Ball-Launch-Data-Performance-Reference-Tables · research:fairway-woods:C4 · Foresight Sports (launch-monitor maker) reference tables, verified by direct page read 2026-08-13. The two vendors converge on the same window shapes, which is what lets these become L0; the whole 80-95 mph male-amateur band off the deck remains unpublished (INTERVIEW §9.18)

  • Smash factor tracks loft, not club type: PGA/LPGA 3W 1.48, 5W 1.47, hybrid/7W 1.46, roughly −0.01 per step up the loft ladder

    the two TrackMan tour sheets above · research:fairway-woods:C3 · TrackMan-published, both populations independently

  • At matched 20° loft, shaft, lie and swingweight, a driving iron launches ~2.3° lower and spins ~700 rpm less than a hybrid off the deck (~0.9°/640 rpm off a tee); the widely-quoted 4° figure is an upper bound for low-launch UDI-style heads. Supersedes the single 4° number in research:heads-design:C21 (decision recorded in CHANGELOG 0.9.0)

    https://exactgolf.com/club-shaft-tests/driving-iron-vs-hybrid/ · research:driving-irons:C1 · Fitting-studio TrackMan test, the only loft-and-shaft-matched comparison published; one tester, so the band is encoded rather than the point estimate

  • Driving-iron candidacy is rare and pattern-gated: under 10% of fitted players qualify (higher ball speed plus excess spin), and published speed guidance (~95 mph 6-iron) sits above the PGA Tour average, so the gate is deliberately strict

    https://practical-golf.com/utility-driving-iron-guide (Woody Lashen, Pete's Golf) and https://sports.yahoo.com/article/play-driving-iron-best-pass-150052871.html (Golfweek) · research:driving-irons:C11/C12 · High-volume independent fitter + equipment-press fitting guidance; practitioner consensus with no published derivation, flagged for founder calibration (INTERVIEW §9.22)

  • On-course amateur data shows the fairway slots collapsing as speed falls: 3W/5W/7W span 24/14 yd of carry at scratch but 12/4 yd at a 25 handicap, so below roughly a 20 handicap two of the three slots are not earning a place

    https://mygolfspy.com/news-opinion/instruction/fairway-wood-distance-chart-whats-average-for-your-handicap/ · research:fairway-woods:C7 · Shot Scope tracked on-course data (mishits filtered) via MyGolfSpy

  • Attack-angle response in the long end is loft-dependent, not club-type-dependent: the 3-wood is the only fairway wood that loses carry to a steeper strike (−1.9 to −5.0 yd at −3° AoA) while 5W/7W/9W gain, and utility irons are near-indifferent (under 2 yd either way). Deltas only: this robot's spin baselines run ~1,000-1,300 rpm above both vendor tables and are not used for windows

    https://www.golfdigest.com/story/fairway-woods-hybrids-irons-robot-testing-insights · research:fairway-woods:C6, research:hybrids:C8, research:driving-irons:C6 (one shared source, counted once) · Golf Laboratories robot / Ping G440 family; well-controlled on deltas, unexplained on levels (cross-conflicts.md 2026-08-13 §2)

What we don’t claim

Numbers-only fitting can’t see lie angle, length, strike location, tempo, or feel. An in-person fitting remains the gold standard; Dialed is the free first step and the second opinion. Accuracy claims will only ever come from outcome data we can show. Until then, you get windows, confidence labels, and sources.

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