"Will Fisher" writes:

A few questions:

1. How tight should the chain be on a fixed gear? I try to push the
rear wheel back as hard as I can into the dropout but when I do a
trackstand, I can still feel the slack in the chain when I switch
from forward to backward pressure. The chain looks perfectly taut
but certaintly does not feel so.

Chain doesn't need to be so tight, in fact it often causes binding
problems in the drivetrain.

2. I ride in NYC where there are thousands of road obstacles
(potholes, manhole covers, etc.) and I'm finding the ride to be
extremely harsh. Any suggestions (e.g. a good fixed gear saddle)?

Track bikes ride harsh because of the short wheelbase. Try a
different type of bike that's actually designed for riding on the
road, if a track bike is what you're riding.