All-Japan Dirt Trial Tyre Choice: A Real-Data Analysis

Tyres divide into longitudinal-groove (for gravel and mud) and block-pattern (for harder surfaces). Main suppliers: Dunlop, Yokohama, Toyo. Fundamental selection principle: softer and more diggable surface means deeper groove; harder compacted surface means block for contact patch maximisation. In 2026, teams increasingly chose wet-type longitudinal tyres even in dry forecast conditions at Sunagawa and Okayama, where dry surface line dig-out makes longitudinal groove more stable.

Continue Reading — 6 Sections

This article is exclusive to WSJ subscribers. Subscribe to read the full article.