Tire Load-Rating Check (per Axle)
Whether an axle is within its tire load rating.
Example
You enter
- Axle scale weight (lb) 12000
- Tires on axle (2 single / 4 dual) 2
- Marked max load per tire (lb) 6175
You get
- Axle tire capacity 12,350 lb
- Utilization 97.2%
- Within the tire rating Yes
Checked against published worked examples from: Michelin.
Details, formula, and sources
ScopeThe axle scale weight checked against the tires on the axle times the marked max load per tire, reporting capacity, utilization percent, and any overload. Use the sidewall's single rating on a steer axle and the dual rating in a dual position; the marking and the AHJ govern.
Formula or tableaxle_capacity = tires_on_axle x tire_max_load; utilization% = 100 x axle_weight / axle_capacity; ok if axle_weight <= axle_capacity, else overloaded by the difference.
Source and edition49 CFR 393.75 (tire load) by section and the DOT tire sidewall max-load marking; not reproduced.
Free accessRead-only at ecfr.gov. The sidewall marking and inflation rating govern; use the single vs dual rating to match the wheel position.
What governsMath aid for personal verification. The ELD on the truck and the carrier tariff are the legal record. State limits may be lower than federal.
API field namesaxle_weight_lb, tires_on_axle, tire_max_load_lb, axle_capacity_lb, utilization_pct, ok
- Single vs dual use the sidewall's single rating on a steer position and the dual rating in a dual position - they differDOT sidewall marking
- Inflation the marked max load is rated at a specific cold inflation pressure; under-inflation lowers capacity49 CFR 393.75
- Not the GAWR this is a tire-load check, not a substitute for the axle's gross axle weight rating (GAWR)manufacturer GAWR