Originally Posted by
edthesped
Okay, I'll follow up with my current experience. I'm building up an AWOL frameset and all is done but the front mountain triple 44/32/22 with Tiagra 4503 is not working well at all. It seems the FD does not quite swing out far enough to easily engage the big ring. I tried switching the hollowtech bb shims from the default 2 on drive side and 1 on non drive to 2 on non drive and 1 on drive. Measured distance between center of seat tube and inside face of middle chainring is ~47.5 mm in the non standard configuration and I can get the system to just barely work but must heavily tension the shift cable in the low position to do so and the derailleur is against the outer extent of the swing when on the big chainring. Issue 2 is the lower end of the cage just barely clears the chainstay and the amount of tension on the cable tends to pull the derailleur down the seat tube. At this point I'm looking at a CX70 FD but am not sure it will have enough swing either as it's made for a double.
On your first problem, yes, a mountain bike crank is a squidge wider than a road crank. Try removing the spacer on the drive side entirely, then reset the front derailer. You shouldn't need 3 spacers on the nondrive side. You can also use thinner spacers. Your local bike shop should have some or they can get them for you. Y
ou can also find them on-line
On your second problem, if the derailer is slipping on the seat tube, you haven't got the clamp tight enough. It shouldn't move at all, no matter how much tension you put on the cable.