I have brakes. I use them, and only them, for stopping.

My drivetrain is pretty compact - 39/15 fg.

I can pull it very tight, but then it seems like it binds a little. At least it doesn't spin as freely.

If I have it so it spins freely, with just a little slack, I can get it to come off if I press against one side by the chainring, but what would actually make it come of while riding?

Will too tight of a chain do damage to my hubs or bottom bracket?

yes, too tight a chain will make your bearings hate you... and your chain... and your chainring...

1/2" play is the minimum i would go. i usually rock around 3/4" and ride brakeless. if your chainline doesn't suck, you're more than fine.

supposedly but I don't know if it really does. For example I was mountain biking last weekend with a guy whose chain was way to tight. However when he pedaled hard slack developed in the bottom. This shows that even a chain so tight that it will bind when the wheels are alowed to spin freely puts less stress on the bike then hard pedaling does. There could still be extra wear from the constant nature of the stress though.

Either way if you push hard enough you can usually get a chain to come off. Why don't you just try it looser and see what happens.

once you go slack, you will never go back...

thanks, some of us are new "after this nap". I have a question to add, if you are using resistance to slow down and your chain is "slack" there is that "no hook up" spot between forward and back... this makes it harder to do track stands right? I'm trying to learn how to do them and find that space annoying? do these guys doing track stand at the lights have their chains really tight?

thanks

Nah, you can still do trackstands will that little bit of take-up in the chain.

Tip for learning to trackstand:

First learn standing up, with your hands on the flats or curves (not in the drops)
This way you aren't using your leg strength, just weight difference on your feet to adjust drivetrain force. Then progress to standing in drops or seated whereever.

Tight enough that it ovals your chainring and cog.