i found a bike on craigslist that i thought looked pretty good so i went out and checked it out and ended up buying it.

its a Specialized Sirrus. no clue how old it is. its a single speed bike. the standover height was 30" so i'm guessing this is 50cm frame.
it felt very light and after test riding i found i liked the upright position more than the drops on a road bike.
when i was in the drops i felt a little unsafe as i'm not used to braking from that position.

when i got home i weighed the bike cuz i was curious and found that it was 20.5 lbs. is that anything special?

i got this for $160. was this a good deal?

is the frame anything special?
can i switch out the single speed to more gears later on? or even make it a fixed gear?
how much would that cost?

oh and i found that the seat on this bike was kinda hard and hurt my butt.
any suggestions on a good replacement seat?

http://aycu39.webshots.com/image/839...5446535_rs.jpg
http://aycu14.webshots.com/image/889...9529297_rs.jpg