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
- 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.
- L1 · Fitting rules. 30 rules (release 0.6.0) 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.
- 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.
- 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 (0.6.0) 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
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
High-MOI driver heads retain ~5–8% more ball speed on heel/toe mishits vs low-MOI designs; near-zero benefit on center strikes
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
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.