2012 Toyota Prius Owners Manual - Page 771

5-2. Steps to take in an emergency Installing the compact spare tire STEP 1 Remove any dirt or foreign matter from the wheel contact surface. If foreign matter is on the wheel contact surface, the wheel nuts may loosen while the vehicle is in motion, causing the tire to come off. STEP 2 Install the spare tire and loosely tighten each wheel nut by hand by approximately the same amount. Tapered portion When replacing a steel wheel with a compact spare tire, tighten the wheel nuts until the tapered portion comes into loose contact with the disc wheel seat. Disc wheel seat Tapered portion When replacing an aluminum wheel with a compact spare tire, tighten the wheel nuts until the tapered portion comes into loose contact with the disc wheel seat. Disc wheel seat 462