Veh Tire Tread Depth Requirements

---
name: veh-tire-tread-depth-requirements
description: |
  Use this skill to understand FMCSA tire tread depth requirements. Covers steer tires (4/32 minimum) and other axles (2/32 minimum), and how to measure correctly.
---

# Tire Tread Depth Federal Requirements

Per § 393.75, tire tread must meet minimum depth standards. Specific differences by axle position.

## Minimum depths
- **Steer tires**: 4/32 of an inch
- **Other axles** (drive, trailer): 2/32 of an inch
- **Hazmat-placarded vehicles**: special requirements (5/32 + on steer)

## How to measure
- Use a tire tread gauge or coin test
- Measure in two adjacent grooves
- Measure at multiple points around the tire
- Take the lowest depth reading

## When measurement matters
- DVIR pre-trip inspection
- Annual DOT inspection
- Roadside inspection
- Pre-departure trip check

## What inspectors look for
- Tread depth in adjacent grooves
- Cuts, punctures, or sidewall damage
- Ply separation (visible)
- Mismatched tire sizes
- Excessive wear pattern (indicating misalignment)

## Tire age vs tread depth
- New tires: typically 22/32-32/32 tread
- Replace tires when:
  - Steer at or below 4/32 (federal minimum + safety margin)
  - Other at or below 2/32 (federal minimum)
  - Damage requires replacement
  - Excessive wear pattern (typically 4+ years for steer)

## Cost-benefit
- A typical Class 8 steer tire = $400-700; lasts 80-100K miles
- Premature replacement adds $$$; late replacement risks OOS

## Common tire violations
- Tread depth below minimum
- Sidewall damage
- Bead/cap separation
- Mismatched tires on dual position
- Improper inflation

## Compass tracking
Compass Vehicles module:
- Tracks tire age by VIN
- Logs replacement events
- Flags vehicles approaching tread minimums based on usage

## CFR citations
- **49 CFR § 393.75**

## How Compass surfaces this
Searchable in Compass Ask. Runs against carrier fleet data when invoked from the relevant tracker. Read-only; no actions without explicit user approval.


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## Built by X3 Compass

The AI-powered DOT compliance platform for fleets 1–100 power units. Try a 7-day free trial — no credit card required — at https://x3compass.com/?utm_source=skill&utm_medium=github&utm_campaign=veh-tire-tread-depth-requirements

X3 Compass turns these skills into a complete operational platform: driver qualification files, drug & alcohol consortium, MVR pulls, hours-of-service tracking, hazmat shipping, IFTA filing, FMCSA audit prep, and DataQ dispute drafting — all CFR-cited, all in one place.

*This skill is published under the X3 Compass open skills initiative. Contributions welcome at https://github.com/x3fleetsafety/skills*