CARB bearings are produced as standard with Normal radial internal clearance and most are also available with a larger C3 clearance. Many bearings can also be supplied with a smaller C2 clearance or with a much greater C4 or C5 clearance.
The radial internal clearance limits are listed for bearings with
The limits are valid for bearings before mounting under zero measuring load, and with no axial displacement of one ring relative to the other.
Axial displacement of one ring relative to the other will gradually reduce the radial internal clearance in a CARB bearing. The amount of axial displacement encountered in cases without external heating of the shaft or foundation will have little effect on the radial internal clearance, see section Axial displacement.
CARB bearings are often used together with spherical roller bearings. The clearance of the CARB bearing is slightly larger than that of the corresponding spherical roller bearing having the same clearance class. An axial displacement of the inner ring relative to the outer ring of 6 to 8% of the bearing width will reduce the operational clearance to approximately the same value as a spherical roller bearing of the same size.