I drew, but was there a win?

Hi all,

this was a game that I ended up just offering a draw that was accepted. I was white in this game. We were dancing around for the last 10-15 moves, my king and his rook. Was there a win here, or was a draw the best I could have reached? I'll link to the source game just in case there was a win a few moves before the dancing started 

http://www.chess.com/echess/game?id=80183772

41. Kb6 leads to pawn promotion after 41. ...Ra1 42. Rb8 ...Rb1+ 43. Kc7 ...Ra1 44. Kb7 ...Rb1+ 45. Ka8 ...Re1 46. a7 ...Re7 47. Rb4 ...Re8+ 48. Kb7 ...Re7+ 49. Ka6 ...Re6+ 50. Rb6 ...Re8 51. Rb8 ... Then what follows is either Re1 to exploit a skewer on the new queen or a flurry of checks pushing the king back down to the safety of the pawns.

The point of it is to get the pawn on the 7th rank with the rook on the 8th and not get checked again or to trade rooks.

As Nighthawk said 41. Kb9 is surely winning

Ah yes Kb6!! Thanks for that. I could smell a win in there. Guess I need to study my end games a little better. Thanks to you both. 

41. Kb4 as you played was OK in that it is still winning. It just takes more moves compared with 41. Kb6. But after 42. a7 black could force a draw. This was checked on Nalimov without the pawns on the king's wing.

Nalimov:   http://www.k4it.de/?topic=egtb&lang=en