Importers of HS 8511.40 (starter motors and dual purpose starter-generators) from Japan actually paid 8.26% on the taxed portion of the value in 2026-06 — 8.21% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 2.5%. Over the window the rate on the taxed portion moved 2.5% → 8.26%, with the largest single step +16.5pp in 2025-05. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 2.5% — importers actually paid 8.26%, so the trade-war overlay added 5.8 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8511.40", origin: "Japan") · see it at trimtabist.com/tariffs
HS 8511.40. The schedule base rate is 2.5%; importers from Japan actually paid 8.26% on the dutiable value in 2026-06 — the trade-war overlay added 5.8 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 2.5% (2023-07) → 8.26% (2026-06), largest single step +16.5pp in 2025-05.
Japan's lower duty (8.21% vs 27.59%) lets it price up to 17.9% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $9.82/kg vs $16.34/kg (duty in, freight out).
14 Chapter-99 measures name Japan; scope mapping is partial (several annexes are PDFs) — absence never means exemption. They do not sum, and some are product-specific — the collected rate above is the composed truth.
All goods from Japan · the whole tariff ledger · reproduce: tariff_story(hs: "8511.40", origin: "Japan") via /connect. Not customs or legal advice.