Originally Posted by tyrion

I just got a Shimano XT 44-32-22 (9 speed) crankset and replaced the 44 with a 48 and the 32 with a 36 so now I have a 48-36-22 crank. Total cost about $150 (I am a bargain hunter).

Originally Posted by cyccommute

One caveat on the mountain crank, it has a wider chain line than your Tiagra. The front derailer won’t be able to move far enough outboard to shift properly. You can move the spacers on the drive side over to the nondrive side and it will shift just fine. I have this set up on a couple of road bikes. Or, since you have mountain shifters to begin with, you could just use a mountain front derailer. Another caveat on the front derailer if you go with a mountain one, don’t go with the highest end. Shimano high end front derailers…road and mountain…are too clever. That makes them sensitive to set up and they tend not to have as wide a range of use as their cheaper brethren. LX and below are far more forgiving on set up and use than the higher end models.