Elad63

I received a second hand cross bike, Motobecane Fantom Cross. It came with a compact double 46/36. I want to put a triple on it, but was wondering if the the Shimano Tiagra 9-speed brifters will be compatible with a triple. I know I will have to change the bb spindle and chainrings. Not sure about the Shimano Tiagra FD triple compatibility either. Anyone ever done this upgrade or have any suggestions, they will greatly appreciated.

Airburst

Shimano brifters come in double and triple versions, so you'll need new ones. The double FD would probably shift a triple, but you might get better shifting performance with one designed for the purpose.

You won't just have to "change the chainrings and BB spindle", you need a complete new crankset. Firstly, triple cranksets have a set of threaded holes in the cranks for the bolts that secure the third chainring, which doubles don't generally come with, and secondly that's a two-piece crankset, the spindle is integrated to the right crank, and thus couldn't be replaced even if it was the only thing you needed to change. OK, you could use the same left-hand crank as before, but I don't think Shimano sells just the right-hand crank/spindle assembly on its own.

Elad63

I know i will have to change spindle and get a new crankset, I was more or less wondering if the shifters will work going to a triple, along with the fd. I already changed the rd to a long cage.

Airburst

Well, as I said, the shifters won't, the FD probably will but not as well as one designed for a triple.

HillRider

The ST-4400 9-speed Tiagra brifters were both double and triple chainring compatible. Later ST-4500 9-speed brifters were double OR triple specific so it depends on which model you have.

bobotech

I have a set of 9 speed Tiagra brifters and they are triple compatible.

I actually did exactly what you are planning on doing to your bike. My buddy and I traded frames, I got his Motobecane Fantom Team Ti frame and he got my Trek 520. He kept the 10 speed drive train.

So I built it up using 9 speed parts. I didn't use my 9 speed Tiagra brifters since i had a nicer pair of 9 speed Ultegras. I bought a used 105 triple crankset that is Octalink v1 with a triple compatible 118.5mm BB. I also used my long cage 105 rear derailleur and 105 triple front deralleur. I do not like using double front derailleurs, they sort of work but not really that well or smoothly. Built it all up and it rides and shifts great now. Chainline looks good.

I am pretty sure that the majority of 9 speed shimano brifters are triple compatible. Just check, swing the lever off all the way past the shift and trim clicks once and then try swinging it all the way again, it should do a second click that pulls the cable a little bit more. If it only does one swing with the clicks and trim clicks but wont' shift again, then that is a double only shifter.

HillRider

That sounds very much like my '96 Litespeed Catalyst. I have 105 9-speed STI's, an Ultegra 6503 Octalink triple crank and bb and 105 long cage and triple front 9-speed derailleurs. It does indeed shift great.
AFAIK, all 9-speed 105 STIs were both double and triple compatible but I'm not sure about Ultegra and particularly Dura Ace. As I mentioned above some 9-speed Tiagra brifters were double/triple compatible and some were not.

Elad63

thx, i will check later tonite when i get home.