The front wheels of a car can get considerably hot due to normal braking because front wheels get the most braking force when brakes are applied. Braking works by converting kinetic energy into heat energy by friction. Some of this heat gets to the wheels via the disc rotor.
Other possible reasons why wheels get hot on a car include a faulty caliper piston that causes continuous clamping of the brake pads, hence the heating. Contaminated brake fluid can cause pitting of the caliper bore, bringing about the same overheating problem. To prevent binding, which also causes heating of the wheels, lubricate caliper bores and mounting pins.