Which mounting approach is used to expand or contract the bearing races?

• A. Direct
• B. Indirect
• C. Temperature
• D. Hydraulic

Answer: (C)

Temperature-based mounting uses heating or cooling to expand or contract the bearing races, creating an interference fit that lets the bearing slip on or off and then grip firmly as it returns to normal size. By heating the outer race (or cooling the shaft) you temporarily increase its diameter so the bearing can be positioned, and as it cools, the race tightens against the shaft or housing. Conversely, cooling the outer race or heating the mating part can achieve the same result. This approach is chosen specifically to control dimensional changes to achieve a snug, damage-free fit, unlike direct or hydraulic methods that rely on pushing parts together or moving them with fluid pressure without exploiting thermal expansion.