The transmission of loads in the bearing of a bottom bracket runs from the inner ring through the balls to the outer ring. The greater the number of balls supporting the transmission of force, the lower the specific contact pressure between the ball and the raceway. There is also a direct direction between the load to which a bearing is exposed and the number of balls that support that force transmission.
Figure shows a schematic diagram of how the load affects different bearings:
Fig. A: Radial ball bearing with large radial clearance. Here a few balls are supporting the load creating a relatively small load zone, easily producing friction and sliding. It is the most common configuration for the bottom bracket shafts.
Fig. B: Angular contact ball bearing with controlled clearance.
Thanks to the preload, the force is distributed among all the balls using the entire raceway to distribute the load, generating a much lower contact pressure. This load distribution reduces the torque required to roll and the greater the demand (sprints, mountain, ..) the greater the difference.
Fig.A Balls Pressure DGBB
Fig.B Balls Pressure ACBB
The amount of load to be applied has to be determined carefully, taking into account several factors such as the required rigidity of the assembly, bearing life, friction of the bearing, as well as the load to be applied (for the bottom bracket is the force of the cyclist that will depend on its weight or power).
APPLY THE EXACT LOAD
The amount of load to be applied has to be determined carefully, taking into account several factors such as the required rigidity of the assembly, bearing life, friction of the bearing, as well as the load to be applied (for the bottom bracket is the force of the cyclist that will depend on its weight or power).
NOISE REDUCTION
Vibrations and clearances are eliminated, avoiding any kind of noise.
