kogel bearings bb90 bb95 bottom bracket
BB90 is a standard used on Trek carbon road bikes only. Bearings drop directly into the frame shell, which is 90.5mm wide and has an inner diameter of 37mm.
The custom spec Kogel bearings are pressed directly into the carbon and only leave room for Shimano or GXP cranks.
*Trek mountain bikes use the BB92 standard, which is called BB86 on their aluminum road bikes. In the past, Trek has used the BB95 variation to this standard on mountain bikes, but modern day Trek MTBs all have a BB92 frame shell.