Crank Brothers’ steel and alloy Cobalt crankset looks gorgeous, but its ISIS bottom bracket looked a decidedly dodgy feature of the design. However, that was before we spent months riding it.
ISIS splined bottom brackets had a lousy reputation for longevity because there wasn’t room for big enough bearings or good enough seals between the large hollow axles and the frame shell. Crank Brothers’ overkill approach uses double-row bearings on the drive side and big push-fit Viton external seals that cover the complete bearing face and, so far, it seems to be working.
The bottom bracket completed the dirty end of autumn and a full winter in the bowels of our deliberately uncleaned ‘Fossil Fuel’ test rig and continued to work without problems. No creaking, no wobbling and no nasty noises despite running much longer than most ISIS bottom brackets we’ve used before. If the 158g titanium-axled Cobalt bottom bracket is too expensive, the steel version (with a claimed 220g weight) is £49.99.