This is a terribly ignorant question, but how can you tell if a bike is fixed or single speed on first glance? Is it brake setup or is there something special about the rear wheel? Maybe the presence of a lockring?

I own a fixie and I've occassionally seen single speeds when I'm at the local mountain bike races, but I can't seem to tell the difference just by looking.

Thanks!
cmh

If you look closely there is a distinct diff between a fixed cog and a freewheel cog.

Watch for the rider to coast. If no one is on the bike, you can easily spot a freewheel, but don't get caught looking too closely lest ye be perceived as a bike thief and your head bashed in by a u-lock.

Dual brakes tend to be SS. A rear disc is definitely a SS. SS freewheels tend to be much shinier than your average fixed cog. And if the rear wheel has a stack of spacers it is a converted freehub wheel. That's all the ones off the top of my head.

Is the rider k3wL or a dope ?

not necessarily... phil makes a fixed/disc moutain hub.

Look for the lockring.
If the cog is in the center of a 1/2" thick cylinder bigger than normal threads. It's a BMX freewheel.

Boom. I'd still say 99% of rear-disc single-cogged bikes are run SS though.

youve really gotta look at the rider. no self-respecing hipster would be caught dead on a freewheel.

I follow them until we go down a hill...but then again, I'm a bicycle stalker.

Good to know as I am considering putting my Avids on the custom fixed frame I'm ordering. I love skidding with a rear disk. I imagine just a little skid with a grab of brake will equal skid city!

Correct me if I'm wrong.

^ they also cost almost $300

there is a much cheaper option if you have a fix/free hub. Though I don't know how well it works.
the atomlab freewheel/disc adaptor....

If the bike is being ridden, I look for derailleurs, then brake levers (one or two?), then pedals, and how the rider rides.

If the bike is locked up, I'll just look at the rear wheel and brakes.

If in doubt say to the the person riding the bike in question- "Is that singlespeed or fixed?

that's pretty much my train of thought also. sometimes I can recognize them by how they take a bump/ pothole or a corner. generally, if someone can stop pedaling to do either of these, they will.

first, i look at myself, and say "what the **** do i care whether it's fixed or singlespeed?"

when they are pushign their bike up a hill are the pedals moving? or still?

totaly not true... they ride singlespeeds with no brakes... cause it looks cooler that way... even after you couldnt stop at all for that intersection and got hit by that bus... at least you can be like... "did you see how cool i looked with out any brakes"

i wonder how i will react the day i seem one of these darwin specials get creamed on the philly streets...
will i point and laugh... or will i cry for humanity still
-pete

Seriously???

Look up Ted Shred in your dictionary.

um.
so i know of a dude who does that--ted shred, whose name gets thrown around alladatime. but you're really saying that there's an epidemic of people riding SS brakeless? i find that hard to believe.

I always watch when they go slow. It isnt so much the coasting, as much as it is the slow motion pedaling that can only happen if you can pull up and push down with the wheel.

You can usually tell with a quick glance at the drive train too, because a free wheel is so much bigger.

Rear wheel is the best way to tell if you can see the hub + cog
Otherwise the the constant pedaling... duh

If it's got a freehub with spacers, then for sure it's SS, unless they're using the Surly fixed thing.

Otherwise if it's a threaded hub. It'll either be Freewheel or Fixed.
You can tell by the the width of the cog/ freewheel.

Freewheels tend to be at least a centimeter wide due to the ratcheting system.
Fixed cogs are skinnier and "SHOULD" have a lockring.

Silly question or not, that's what I ask myself every time I visit the Fixed Gear Gallery. By the answers given to you, I wonder how many single speeds may be "pretending" to be fixies in the gallery.

That would be the lamest thing in the world.