Toward a Watch Comfort Geometry Framework: A Geometric Hypothesis for Comfort Thresholds in Wristwatch Wearing

This paper proposes the Watch Comfort Geometry Framework as a companion to the published Watch Fit Geometry Framework. Where the Fit Framework answers whether a watch fits a wrist geometrically, the Comfort Framework addresses a distinct question: does the watch sit comfortably on the wrist during normal wear and physical activity?

Four comfort axes are proposed: Case Height Clearance (H_case ÷ WD ≤ k₁), Crown Clearance ((W − D) ÷ 2 ≥ P_crown + ε), Lug Span Clearance ((W − LS) ÷ 2 ≥ ε_lug), and Strap Contact Pressure (LW ÷ W ≥ k₂). Two of these axes share the (A − B) ÷ 2 structural primitive of the Fit Framework, confirming that bilateral clearance geometry is a fundamental property of wristwatch wearing across both fit and comfort domains.

The paper introduces the Dynamic Comfort Allowance (DCA = ΔC ÷ 2π) — a geometric formalization of wrist circumference increase during physical activity and its direct effect on strap tightness. The DCA provides a quantitative basis for the industry practice of wearing watches looser during exercise and explains the popularity of micro-adjustment bracelets. The specific magnitude of ΔC during exercise is identified as an open empirical problem — no published study has measured this in the context of watch wearing.

Six open problems are identified: an empirical ΔC dataset, wrist depth (WD) measurement standard, crown protrusion (P_crown) dataset, lug span (LS) measurement standard, empirical threshold validation (k₁, k₂, ε values), and a treatment of crown position as a categorical variable.

This paper plants the flag. The territory is claimed, the axes are named, the formulas are proposed, and the path to validation is mapped.

Related publications: DOI 10.5281/zenodo.20389138 (Fit Axis 1), DOI 10.5281/zenodo.20449108 (Fit Axis 2), DOI 10.5281/zenodo.20500447 (Fit Axis 3), DOI 10.5281/zenodo.20496188 (Fit Vector), DOI 10.5281/zenodo.20449213 (Framework v2).