This week at Ruckus we’ve been keeping busy–we’ve seen over 30 bike repairs come through the door! One of the more interesting projects we got our hands on this week was a bottom bracket shell replacement on a 2012 Cannondale Super X.
These Super Xs are great bikes. They’re lightweight, they’re fun to ride and they can be great choice for ‘cross.
Another thing we know about these carbon fiber bikes is that they use an alloy BB30 bottom bracket shell. As most cyclists can attest, aluminum and carbon just don’t play well together in wet conditions …conditions like those found on cyclocross courses in the Pacific Northwest.
The new and the old.
This bike–like most good PNW CX bikes–was ridden hard and put away wet. This, and the interface between the frame’s carbon and the shell’s alloy caused the BB shell to begin to corrode. A creaking sound caused by the corroded adhesive bond was what alerted our customer to the problem.
We begin our repair by removing the old shell. It’s a labor intensive process …we’ll leave it at that.
Above is a shot of the frame, its original BB shell removed. You can see the gaps inside where the chainstay tubes meet the frame shell.
Now, our preferred BB shell replacement is a Press Fit 30 shell. We get these made for us by ENVE. It’s a simple format to work with and the benefits are pretty convincing: no creaking, super strong, super light.
Voila! A new BB shell!
There are a couple of side benefits to this swap-out as well:
- 1) This Cannondale can now be run as a single speed with an eccentric BB. Someday we’d love to build up an ultra-light Super X single speed rig…
- 2) The new shell stiffens up the BB area. Stiff is good!
As always, it’s fun to see the way we can take a damaged bike and return it to the trail, road or the race course, as good or better than new.