Why ride a fixed gear?
This is a difficult question to answer on as impersonal a medium
as the Web. The best analogy I've been able to come up with is that
riding a multi-speed bike -- and especially one with index shifting --
is like driving a car with an automatic transmission. Riding a fixed-gear
bike (or a single speed, to a lesser extent) is like driving a sports car
with a manual transmission. Other than on a freeway during rush hour....
Riding fixed puts you closer to the pavement. You know when
the road turns up or down. Simple maneuvers like turning require that
you concentrate fully on your relationship with the bike.
Riding fixed is an incredible workout. Think for a minute how
often you coast during a ride. On a fixed gear, you can't coast. Ever.
If you don't use your brakes (a strategy I no longer advocate: it's pretty
hard on the knees), downhills become the toughest part of your rides.
The first time I rode fixed, I was hooked. Maybe that's why I believe
that experiencing it is the only way to really understand. Try borrowing
a fixed gear bike from a friend if you can. You'll have a hard time
giving it back.