This press-in bottom bracket is specifically designed for original aluminum Pivot Cycles. These frames have protrusions inside the BB shell that prevent the use of standard BB sleeves. In addition, the press fits were unusually tight, sometimes over-compressing the bearings. Our aluminum cups are machined to the perfect tolerance to fit the Pivot BB shells. The bearing-to-cup clearance has also been custom engineered to prevent ovalized BB shell tubes from distorting the bearings--leading to much longer bearing life than the OE bottom brackets provide. The machined aluminum center sleeve is a special narrow design that won't interfere with the extruded supports that protrude inside the Pivot aluminum BB shells.