warm bottom bracket clicking
 

My fixed gear has a Shimano UN53 bottom bracket. For the past several days, the bike is super quiet in the morning at about 55 F. However around lunch when I ride it home, I have a nice clicking sound from BB area after everything has warmed up. Is this typical of a bottom bracket failure? Do I just need to replace it or is there any servicing of a UN53?

it might just be a little loose, although if that were the case the problem should get better with warmth. before you even touch it, try taking your crank bolts out, greasing them, and putting them back in tight. i had a clicking driving me crazy for a while that i swore was the bb, but turned out to just be a loose crankarm.

If it's too loose, it probabily would be a constant grinding regardless of the temperature, what it sounds like is that it's just tight enough to not click when it's cold, but does click when it warms up and expands. Try loosening it just a tiny tiny bit and see if that makes a difference.