Wis. Admin. Code § Trans 305.40 – Fenders and bumpers.

(1) A fender over each rear wheel is required on every motorcycle except those originally manufactured without a rear fender. A front fender is required on every motorcycle manufactured after March 1, 1996. The fender shall cover the complete tread width area of the tire and lengthwise from 15° to the front and 60° to the rear when measured at the center of the axle to the top of the tire on a vertical plane.
(2) Every type 2 motorcycle shall be equipped with a rear bumper which meets the requirements for a homemade or reconstructed vehicle under s. Trans 305.18.

History: Cr. Register, February, 1996, No. 482, eff. 3-1-96.