Originally Posted by
Kontact
As I said, the Alivio crank design always has an odd number of spacers. That's the way it is designed and what it shows in the manual I gave you a link to. It has the extra spacer because that spacer is sometimes replaced with a FD mount ring. So it should have two on the drive side if your bb shell is 68mm wide. Might be worth measuring your BB shell.
The other thing that can make your crank stick out is a spacer on the spindle itself under the spider. You would notice this as a possible cause if the crank arms are different distances from centerline. You can measure this by measuring from the seat tube out to each crank arm. That distance should be roughly symmetrical.
Using the same technique, you can measure your chainline going from the center chainring to the front center of the downtube or seattube. Center to center should be around 47.5mm. What is yours?
Is your Tiagra FD a band type or is it mounted on a band adapter?
Square taper mountain cranksets have the same dimensions as HT mountain cranksets. Your issue is that something isn't working when you went from road triple to mountain triple.
It doesn't sound like your cable is an issue. But people sometimes mount the cable above or below the bolt when it should be the opposite.
BB shell = 68mm
There is a difference in distance from seat post to each crank arm of 5mm.
Tiagra deraiilleur is a band type.
Distance from centre of seat tube to middle ring is, I would say, more likely to be 50mm than 47.5 but that is using a retractable tape measure and eyeballs; harldy precise.
I realize, now, that I ought to have taken some measurements with my old crankset, for comparison.
I'm not sure the old crankset was a "road" crankset though I honestly don't know what determines "road" vs "MTB" vs "whatever" beyond the installed tooth counts (it doesn't seem to be the ring count; any can have 1-3 apparently); is there a difference between the various designations in where in space the rings sit relative to a common point of reference?
I dont understand what you mean by "people sometimes mount the cable above or below the bolt when it should be the opposite." I see just one bolt to crimp the cable and just a single, short, obvious path from crimp bolt to under-BB cable guide.