Fixed gear bicycles have been around for years but recently they've become more popular, so some folks think of them as something new and hip. Now my kids will tell you that I've never been hip but I was riding fixies back before they were cool and I'll probably still be spinning around the streets on a fixie even when hoverboards or Jetson fold-into-a-briefcase cars become the next big thing.
Sheldon Brown has written and collected a whole bunch of info on fixed gear bikes and if you are at all interested in the subject, you should head on over to his fixed gear page.
A lot of fixed enthusiasts go all Zen and mystical when they try to explain what makes riding a fixed gear different. There certainly is a oneness that is explained better by one ride than ten thousand words and like a Zen Koan words can sometimes point the way. But remember as you read my words or Sheldon's, that a pointing finger is not the moon. Find a fixed gear bike and ride one. As Mark Twain said "You will not regret it, if you live."
Here is the main thing about a fixed gear bike: It Doesn't Coast. Yeah, you only have one gear but the big thing is that the bike does not coast. It only goes when you pedal. That makes it very different and it actually makes it very fun.
A fixed gear bike is a creature of momentum. Once in motion, it wants to stay in motion. On a coasting bike your legs bring things up to speed but if your legs can't keep up, no problem. You coast or shift up to a higher gear. On a fixie, you have to keep up and there is no higher gear. What gear you have is what you use.
On a coasting bike, you slow with your brakes. On a fixie, you can slow by pedaling slower. Some young, strong and idealistic riders ride fixies with no brakes other than the fixed wheel and slow only with the strength of their legs. Most folks with a respect for physics and a desire to live opt for at least a front brake. Old, un-cool people like me have both front and rear brakes on their machines. With brakes and a fixed wheel, you can stop a fixed gear bike as fast as anything with multiple gears.
This non-coasting thing is all the differerence. You have to be strong on the climbs and you must spin quickly on the descents. There is no other choice, there is no other way. Well, there is the way of coasting, the way of multiple gears, but that is not the fixed way. You do not try a fixed gear. You ride or ride not. There is no try. If Yoda rode a bicycle, I am sure he would ride a fixed gear.
It is easy to see the lack of the ability to coast and shift gears as burden but riding reveals a more liberating truth. Fixed gear bikes pedal themselves through the dead spot in your pedal stroke. Climbing hills is easier than you thought it would be.
Fixed descents are more frightening than any climb but fear is only a signpost quickly glimpsed and passed as you spin faster than you ever knew you could spin.The bike is less than you thought you needed and you become more than you knew you could be.
Your bike will remind you of the limits of man and machine but by clearly marking out those limits, you will learn where you can push. You will become stronger on the climbs, faster on the descents. Your machine is simple and silent, your legs become strong and fast.
Fixed gear riding is not for everyone. Multiple gears and coasting are things that many people find useful and fun. But a simple, silent bike that only goes when you pedal may be ride of your life.