55 makes set in a dangerous flop

Big blind is loose passive. No information on the other guy. What do you think of my line here?

PokerStars No-Limit Hold'em, $0.10 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP ($10.55)
Button ($2.80)
SB ($6.45)
BB ($5.55)
Hero ($9.80)

Preflop: Hero is UTG with 5http://www.flopturnriver.com/phpBB2/...miles/club.gif, 5http://www.flopturnriver.com/phpBB2/...iles/heart.gif.
Hero raises to $0.4, 1 fold, Button calls $0.40, SB calls $0.35, BB calls $0.30.

Flop: ($1.60) 7http://www.flopturnriver.com/phpBB2/...iles/spade.gif, 9http://www.flopturnriver.com/phpBB2/...iles/spade.gif, 5http://www.flopturnriver.com/phpBB2/...iles/spade.gif (4 players)
SB checks, BB checks, Hero bets $1.3, Button calls $1.30, SB folds, BB calls $1.30.

Turn: ($5.50) Khttp://www.flopturnriver.com/phpBB2/...iles/heart.gif (3 players)
BB checks, Hero bets $5, Button calls $1.10 (All-In), BB calls $3.85 (All-In).

River: ($15.45) 3http://www.flopturnriver.com/phpBB2/...iles/spade.gif (3 players, 2 all-in)

Final Pot: $15.45

Postflop is fine. Preflop are you regularly getting that many callers? If the table is playing loose enough to stack off with lukewarm hands in unraised pots then just limp preflop and take chunks out of top pair when you hit. You only need to raise preflop on tight-ish tables.