Brake Pad Lifespan and Heat Capacity
KE per stop, rotor temp rise, wear per stop, estimated pad life by material.
Example
You enter
- Vehicle weight (lb) 4000
- Speed delta per stop (mph) 30
- Stops per mile 1
- Pad thickness (mm) 12
- Pad material ceramic
- Rotor mass (lb) 18
- Pad-set cost ($, optional) 80
You get
- KE per stop 163.14
- Rotor temp rise per stop 8.69
- Estimated pad life 8172 mi
- Cost per 100k mi (if $/set supplied) $979.00 / 100,000 mi
Details, formula, and sources
KE (BTU) = 0.5 × m × v² converted via 1 BTU = 778 ft-lb. Rotor temperature rise ΔT = KE / (mass_rotor × specific_heat). Wear rate by pad chemistry: organic / semi-metallic / ceramic typical mil-per-stop benchmarks.
Classical kinetic-energy theorem; SAE J661 friction test, SAE J2522 (brake performance) by name; manufacturer pad-chemistry technical bulletins (Akebono, EBC, Hawk, StopTech).
SAE licensed; physical-fact derivations free in mechanics texts.
Estimate. AHJ and licensed professional govern.
Field names used by the API: vehicle_weight_lb, speed_delta_mph, stops_per_mile, pad_thickness_mm, pad_material, rotor_mass_lb, pad_set_cost_usd, ke_kJ, rotor_temp_rise_C, miles_until_worn, cost_per_100k_miles_usd
- Specific heat (cast-iron rotor) 0.108 BTU/lb-°Fengineering-practice value
- Wear-rate ranges organic ~ 0.5 mil/stop; semi-metallic ~ 0.3; ceramic ~ 0.2 (typical)manufacturer technical literature