I’ve had a British threaded Omas Titanium bottom bracket with rather nasty bearings in the parts box for a little while and I thought it would be perfect for this build. All it needed was new sealed bearings! The original bearings are steel but there are plenty of ceramic alternatives available.
The size of bearing required for this axle is ‘6903’ with measurements of 30 mm outside diameter, 17 mm internal diameter and a 7 mm width. These bearings arrived yesterday.
There are no complicated tools for removing and replacing these bearings, just a little bit of patience.
My frame has extremely good paint and threads considering its age, but as this bottom bracket has alloy cups, that don’t have perfect threads on them, it’s a good idea to prep the frame threads, just to make sure the cups don’t snag as they are fitted.
If you care for your tools, always use a good cutting fluid, even if you are just chasing and not actually cutting, this stuff will help to make your valuable tools last longer. I use Park CF-2 – don’t be tempted to just use normal oil.
The cups and lock rings on this bottom bracket are all standard Campagnolo fitting. Use good tools and lots of anti-seize compound on the threads and wind the cups in carefully. Use a lock ring, threaded partially onto the cup to check that it is going in straight. The axle will move side to side until all the slack is taken up. Tighten the lock rings and you are all done.
Once I’ve got a chainset, I might need to slightly adjust the cups depending on the chain line that I get. The last thing to do was to fit the bottom bracket gear cable guide.
This guide came with the frame and simply snaps into location.
So what’s next… maybe a Huret rear mech and Simplex gear levers…