Importers of HS 8483.90 (chain sprockets and parts thereof) from Mexico actually paid 18.03% on the taxed portion of the value in 2026-06 — 14.98% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 2.8%. Over the window the rate on the taxed portion moved 2.7% → 18.03%, with the largest single step +18.3pp in 2025-03. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 2.8% — importers actually paid 18.03%, so the trade-war overlay added 15.2 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8483.90", origin: "Mexico") · see it at trimtabist.com/tariffs
HS 8483.90. The schedule base rate is 2.8%; importers from Mexico actually paid 18.03% on the dutiable value in 2026-06 — the trade-war overlay added 15.2 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 2.7% (2023-07) → 18.03% (2026-06), largest single step +18.3pp in 2025-03.
Mexico's lower duty (14.98% vs 42.4%) lets it price up to 23.8% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $7.78/kg vs $103.49/kg (duty in, freight out).
5 Chapter-99 measures name Mexico; 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 Mexico · the whole tariff ledger · 8 CBP rulings cite this code · reproduce: tariff_story(hs: "8483.90", origin: "Mexico") via /connect. Not customs or legal advice.