Why rolling resistance matters
Tire rolling resistance is the force lost while a tire deforms and recovers on the road. It may look small, yet it runs every second the vehicle moves. Electric vehicles feel it strongly because it converts battery energy into heat. A lower coefficient can improve range, reduce motor load, and make trip estimates more stable.
This calculator focuses on the rolling part only. It does not include aerodynamic drag, braking loss, bearing friction, or accessory power. That separation is useful during tire studies. It helps you see how load, pressure choice, road grade, and speed affect one loss channel. When you later add drag, you get a clearer full vehicle model.
Electrical view
For an electric drivetrain, rolling force becomes wheel power. Power is force multiplied by road speed. The tool then divides wheel power by drivetrain efficiency. That gives estimated battery input power. Battery current is input power divided by pack voltage. These values help size conductors, check inverter demand, and compare tire choices.
Speed does not change rolling force directly in this simplified method. It changes power because the same force acts over more distance each second. Energy per kilometer stays near constant when efficiency is fixed. Trip energy rises with distance, load, and coefficient.
Better inputs, better decisions
Use measured mass when possible. Include passengers, cargo, tools, and trailer tongue load if they are carried by the tires. Select a coefficient that matches the tire and surface. Efficient road tires may have a low value. Off-road or underinflated tires may have a higher value. Grade changes the normal force through the road angle.
The torque result uses rolling force and tire radius. It shows how much tire torque is needed just to overcome rolling resistance. Per-drive-tire torque divides that value by the selected driven tires. This is not total launch torque. Acceleration and slope-climbing torque must be added separately.
Practical use
Run a baseline first. Then change one input at a time. Compare low rolling resistance tires, heavier loads, or slower routes. Export results when you need a study record. The example table gives starting data. Replace it with your measured values for final design. Document assumptions so later comparisons remain fair always.