Speed is in the details.
Shimano spared no detail when redesigning their Dura-Ace group, and the BB86/BB92 compatible press-fit bottom bracket got the star treatment as well. Compared to previous versions, it's both lighter and more efficient, while remaining an industry leader in weather resistance and durability.
Slightly smaller bearings allow for more efficient rolling while furthering weight reduction, and updated seals drop resistance by a claimed 50%, reducing effort required throughout the pedal stroke with no sacrifice in weather resistance.
The Shimano Dura-Ace BB92-41B Press Fit Bottom Bracket is compatible with BB86 / BB92 bottom bracket shells with 86.5 mm / 91.5 mm widths and 41 mm inner shell diameters. Compatible with the 24 mm spindles found on Hollowtech II cranks.
B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.
Bottom Bracket STD: PF24
Mfg PartNum: ISMBB9241B
Bottom Bracket Type: Shimano (24mm)
Frame Interface: BB86/92
Shell Diameter: 41
I bought this as a replacement for one with 16,000 miles of year-round riding in NW CT but I haven't installed it yet because the old one is still quiet and smooth.
It's kind of unreal how durable these are.
I spray enough water to rinse off road salt and grit and that's about it for maintenance.
If installed correctly you get the best of what Dura Ace offer, total performance in pedaling. Note well that the left and right bearing cups are not labeled LR, and are weighed the same so if you get them mixed up good luck sleeping at night. The orientation is printed on the inner core sleeve. One must assume that the packaging is vigorously QA from factory to the day you get it in your hands. 41A is the MTB version.
I upgraded to Ultegra so of course I wanted to switch out the bottom bracket. I honestly can't say whether or not this improves performance over the old version but it certainly does not hinder it. I would have love to buy a Ceramic Speed or Chris King bottom bracket but for the price it's hard to beat this one.
The bottom bracket fit perfectly in my BB86 frame. Weighs 54.7 grams on my scale with all the green grease Shimano loaded it up with. Total width about 90mm, diameter that enters frame 41mm, interior diameter 24mm (fits newer Shimano road spindles).