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SESK: Stuff Everyone Should Know · sesk.info/cdl-inspect-front-tire-tread

What is the minimum tread depth for front (steering) tires on a commercial vehicle?

4/32 inch in every major groove.

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  1. 2/32 inch
  2. 4/32 inch ✔
  3. 6/32 inch

Why: Front tires need at least 4/32 inch of tread in every major groove. Other tires need at least 2/32 inch. No fabric should show through the tread or sidewall.

Huh, didn't know that: Recapped or regrooved tires are banned on the front wheels of a bus.

The dad joke
Why did the tire go to the bakery? For a fresh tread.
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References

Answer: 4/32 inch. Front tires need at least 4/32 inch of tread in every major groove. Other tires need at least 2/32 inch. No fabric should show through the tread or sidewall.

  1. California Commercial Driver Handbook (DMV) www.dmv.ca.gov/portal/file/california-commercial-driver-handbook-pdf
    You need at least 4/32 inch tread depth in every major groove on front tires. You need 2/32 inch on other tires.
    Checked 2026-10-10.

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