I wouldn't mind having a small mechanical spoke odometer mounted on the fork.

I think I'd rather have one of those lights, it'd be nice to not have to worry about batteries in a pinch. Plus you could keep track of your cadence by keeping it at a constant level of brightness...

I put one on my IRO build, which is my daily commuter, and I love it. I'm always glancing at my speed, and measuring the distance of my rides, seeing what my max speed was that day. I'm not into riding around on some faux-track bike pretending to be a messenger, so I don't care if my bike has a small computer strapped to the handlebars.

I had one on my old Trek 6000, but never really looked at it. When the battery died without me noticing, that's when I decided that I didn't really need it.

I put a mount on mine for doing cadence drills and for when I feel like logging the ride data. Otherwise, I just count it out with a watch.

Get one of these:

Raging against the Man.

If there's an NJS speedometer, hipsters will buy it.

everything in japan is cooler

i can always count on awesome pictures on page 2 in threads like these

I have a wireless one on my road bike. I think I'll buy a second mounting kit and put it on my FG. Then I can just swap over the computer depending on the bike I take.

I found peace when I finally lost my last speedometer. I´m never looking back.

They do help one to hold a steady speed when pulling in a paceline.

you could always count cadence and multiply it by (something, i forget what. its something to do with gear ratio and wheel size. check sheldon brown).

i hate bike computers though, because i've had to repair so many broken ones at the shop. it's more of a hinderance than a help.

how many of us ride fixed in a paceline?

its not too hard to keep the same pace on a fg.

I wish I had a powertap sometimes but 95% of my riding on my fg bikes is for fun, with friends, or just bombin around town.. times when its best to just pay attention to traffic and not a computer.

yeah, I can't believe no-one has identified the most obvious reason not to have one.. If I put one on the bike it'd be stolen within the week..

I'm waiting for the next season of "Ninja Warrior" to feature fixies in downtown Tokyo.

Yes, I try to be courteous and confirm the paceline speed when it's my turn to pull. It's extremely rude to jack the pace up when it's your turn to pull and drop the last guy off the back.

I don't have a speedometer on my fixie, though. For the type of riding I do with the bike it's unnecessary. Sometimes I think I'd like to have one but not really enough to actually buy one.

I use a wireless GPS speedo with a built-in HR monitor. I guess I'm not a hipster. Oh well.