Virtual Swing Weight
Lorythmic · 14″ Fulcrum
How it works

The physics behind
swing weight

Swing weight measures how heavy a club feels when you swing it — not what the scale says. It's measured around a 14″ fulcrum from the butt of the grip and reported on the Lorythmic scale (A0 → G10), where most tour players sit between D2 and D5.

The Formula

Physics of the Lorythmic scale

We sum the moment of each component about the 14″ fulcrum, in oz·in:

moment = Σ (massᵢ × (positionᵢ − 14″))
SW points = (moment − category baseline) / 0.875

Components considered: head, shaft (with manufacturer-published balance point), grip, grip tape, ferrule, and any tip weight. The category baseline is calibrated against tour-standard reference clubs measured on a Mitchell machine.

URL Analysis

What the URL analyser does

  1. 01Fetches the listing page server-side, so CORS doesn't apply.
  2. 02Strips noise and extracts visible text and meta tags.
  3. 03Sends it to an AI model that extracts head, shaft, grip and length — flagging any spec it had to infer from the make/model.
  4. 04Computes the swing weight with a confidence band proportional to how much was estimated.
Limitations

Be honest about accuracy

⚠Listings rarely state shaft balance point or exact head mass — we infer those from our component DB.
⚠eBay listings are free-text and unreliable. GolfBidder and Replay Golf are cleaner.
⚠JS-rendered or login-walled pages can't be scraped without a headless browser.
⚠Always measure on a real swing-weight scale before tournament use. ±1.5 SW points is the realistic accuracy of an estimate.
Roadmap

What's coming

v1.1Save builds with login
v1.2Component images
v1.3Scheduled scraping of manufacturer spec pages (admin-moderated)
v1.4Full set builders (compare across irons), MOI option