Trips on the river

[Siegmund]

A very loose $2/4 game. Five or six people seeing most flops, maybe half the hands raised preflop. My first orbit at the table; the only player I recognize wasn't involved in this hand.

Hero has [img]/images/graemlins/diamond.gif[/img]8 [img]/images/graemlins/diamond.gif[/img]7 in the hijack seat.

UTG calls, 2 folds, MP1 raises, MP2 coldcalls, hero coldcalls (questionable, but expecting at least 5 and likely 6 players to the flop, seemed justifiable), CO folds, button folds, SB folds, BB calls, UTG calls.

Flop: [img]/images/graemlins/diamond.gif[/img]K [img]/images/graemlins/heart.gif[/img]7 [img]/images/graemlins/club.gif[/img]6. (10SB)

Check, check, preflop raiser bets out, everybody calls. Between the rainbow flop and the backdoor draw, felt like it was worth peeling one off.

Turn: [img]/images/graemlins/heart.gif[/img]9 (7.5BB)

Check, check, preflop raiser leads again, call, call, call, fold.

Hero has now picked up a 1-card OESD, and it feels like a straight ought to be good, noone likely to play J8, so ten outs now. I don't expect everyone to stay in if I raise and not sure there's any point in a free showdown. Secondary question: how clean do you think your outs are and IS there a case for raising here?

The river: [img]/images/graemlins/club.gif[/img]7 (11BB)

Hey, our ship came in! BUT...

UTG wakes up and leads. Both middle players call. Your turn....

What could UTG have? How often do you think your trips with no kicker (board's K9 plays) are winning?