On a fixed gear it's extremely easy to check chain tension through the cranks...when not moving, put forward pressure on the cranks, then backward pressure. If the crank moves a bit but the rear wheel doesn't, there is play. If you look at the chain while doing this, you can see the chain bounce around, too. You can't really check chain tension this way on a bike that coasts.

Judging from those statements I don't think you understand chain tension / chain slack.

Enlighten me. The second statement is referring to pedaling (thanks ismellfish2 ) the chain on.

You seem to be implying that a chain should appear to visually sag on the lower run. This is not correct.

lube your chain, idk why that would ahve to do with it, but a guy i know never lubes his chain, sounds like a just married car with cans dragging when he comes by, and when i try to skid on his bike his chain skips teeth,

tighten your chain, you have drop outs for a reason

do you have the correct chain? ex. 1/8th cog & chain ring with a 1/8th chain? my friend didnt know the chain he was buying was a 16th and it was skipping teeth really badly

You misunderstood me. I was saying that if the chain falls off and you hook it onto the top of the chainring to pedal it on, the lower part of the chain that isn't engaged on the chainring just hangs loose until the crank turns far enough. once it's on it's not loose.

Put it back on.