[mntndrew]

I agree with Sean that the size of the pot doesn't matter in deciding whether or not to bet on this street. We're trying to decide if we have enough equity to make a bet profitable *on this street*.

Let's say our equity against our opponents' ranges is fixed at 30%. If you have to pay 3 BB's to win, say, 16.5 BB (8.5 + 2 people playing for 3 BB + 2 more BB on the river), then your turn play has been +EV. However, on this street, you put in 1/3 of the bets owning less than 1/3 of the pot. The +EV comes from the padding of the pot by the loose flop and preflop callers, but you actually lost money on this street. I like to think of this kind of play as spending the positive expectation that I made on an earlier street; it's fine, but if you can take a free card it's usually worth it.

That said, I think, as has already been said, that a bet here is close. You're unlikely to be c/r'ed, and 3 callers is probably enough to make it close to profitable. At the same time though, you have to worry that if you get that many callers, your outs may not be clean. I check behind.