Tired of ISIS bottom brackets that last only a season or two? The larger ISIS spindle leaves less room for the bearings. Most high-end bottom brackets use pressed-in cartridge bearings with tiny balls that wear quickly.
SKF designed their cartridge bottom bracket from the ground up to optimize strength and durability. The bearings run on races ground directly into the spindle and the shell, so SKF can use larger balls and rollers for optimum durability. For example, the non-drive-side balls measure 4.5 mm in diameter.
To keep the bearings running smoothly, SKF designed and patented multi-stage seals that retain the grease and keep out water and dirt. Other modern cartridge bottom brackets, even the most expensive models, are relatively simple designs with exposed bearings that are separated from the elements only by rubber dust shields, which are not designed to keep out water.