Jeffrey H. Guffey, 31, told police he was riding a bicycle Wednesday when he shouted at the driver of a sport-utility vehicle that was speeding down a residential street.
Guffey told police the driver pulled over, got out, knocked him to the ground and began biting his ear, spitting out the pieces.
New Castle Police Chief James Nicholson said "a good chunk" of Guffey's left ear was torn off. Guffey was treated at a hospital.
Police charged the driver, 43-year-old Curtis A. Cross, with battery.
Cross, a New Castle resident, has been released from the Henry County jail after posting a $3,250 bond.