How to use this calculator
- Enter vehicle mass. Use the vehicle test weight.
- Enter speed change. Set initial and final speeds.
- Enter brake split. Set front brake bias and rotor masses.
- Read temperature rise. Review energy per rotor and estimated temperature rise.
How it works
Stop energy is 0.5 x mass x (initial speed^2 - final speed^2). The calculator splits that energy by brake bias and divides by rotor mass and specific heat to estimate rotor temperature rise.
Use the stopping distance calculator for the same speed change, or the brake bias calculator to estimate the front/rear split.
Worked example
Verified against the live calculator
A 1500 kg vehicle stopping from 60 mph has about 539 kJ of kinetic energy to remove. With 70% front bias and 8 kg front rotors, the simple front rotor rise is about 51 C, or 92 F, for one stop before cooling.
Frequently asked questions
What is brake stop energy?
It is the kinetic energy removed from the vehicle during the entered speed change.
Why divide energy by brake bias?
The front and rear brakes do not absorb equal energy when brake bias is front or rear heavy.
Does this predict actual rotor temperature?
It is a simple lumped heat-capacity estimate. Real rotor temperature also depends on cooling, pads, calipers, airflow and heat rejection during the stop.
Can I model repeated stops?
Use stop count as an equivalent repeated-stop multiplier when assuming no cooling between stops.
Method & assumptions
- Assumes brake energy goes into the rotors according to the entered brake bias.
- Pads, calipers, hubs, cooling air, radiation, conduction and fade chemistry are not modeled.