TreadSize

Tire math reference

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Garage tire fitment bench with TreadSize OE baseline, diameter tolerance, and clearance notes

We read every message sent to hello@treadsize.com.

What to include

  • Data corrections: if you spot a calculation error, include the tire size, what the tool showed, and what you believe the correct value should be (with a source if you have one).
  • Guide feedback: link to the guide page and describe the section.
  • General questions: fire away — we will respond as time allows.

Response time

We typically respond within 2–5 business days. We do not offer real-time tire fitment advice — for that, please consult a local tire professional who can inspect your vehicle directly.

Sources, review and limits

Last verified

June 2026

Author and reviewer

Written by TreadSize editorial desk; reviewed by Automotive fitment review.

Primary data sources

  • Tire size math from ISO-style tire notation formulas
  • Original-equipment size references supplied by users or vehicle placards
  • Fitment-risk thresholds documented in the calculator

Tire fitment output is a planning estimate. Wheel width, offset, suspension, load rating and local rules matter. Confirm OE specs and safe fitment with a tire professional before driving.