Initial clearance

- For bearings with external diameter lower than 200 mm, measure initial clearance as illustrated in Figure 1.
- For bearings with external diameter larger than 200 mm, measure clearance as illustrated in Figure 2. The initial clearance will be half the sum of the measures shown in the illustration.

Residual clearance

- After tightening the nut, measure the residual clearance as illustrated in Figure 3. The residual clearance will be half the sum of the measures shown in the illustration.


Figure 2 - Clearance measure on large-sized bearings (D > 200 mm)


Figure 3 - Clearance measure after installation


Turn test

Having finished the installation, the turn test should be performed to confirm the bearing is placed correctly.

Small sized machines are moved manually to check turn smoothness.

Large sized machines should be activated without load and turned off immediately, as they do not allow manual movement. During inertia movement, check whether there are abnormalities or not. The test must be initiated without load and in low rotation, which must be gradually increased up to normal operation conditions.

The items to be checked in small and large sized bearings are: vibration, noise, small jolts due to strange particles, galling, crushing, torque inconsistence due to installation fault, seat faults, excessive torque due to very reduced clearance, sealing friction and disalignment.

Table 1 – Radial internal clearance of self-aligning spherical roller bearings