Originally Posted by
cudak888
Even though external-bearing BBs are nice, they're not necessarily the first thing you'll find at a remote bike shop in an emergency. If you plan to do touring in remote areas where picking and choosing an LBS isn't an option, I'd recommend sticking with a simple JIS square taper BB spindle and crankarm. That's the most common crank you'll find at any bike shop - especially those way out in the middle of nowhere.
-Kurt
Thanks! As Eggman said in the above post, it's most likely the mismatch between my FD and crankset. I will definitely take your suggestions about square taper cranks into consideration though as I do plan on doing some touring and am not sure how out of the way I plan on going.
Originally Posted by
Eggman84
I have done a little research (partly to satisfy my curiosity) and this is what I have found. The Tiagra FD-4503 is designed for a 45mm chainline (per the service instructions at
https://si.shimano.com/pFD-4503dfs/s...0A-001-ENG.pdf). The MTB FC-M530 crankset has a 50mm chainline using the recommended 113mm BB (per page 51 of the archived Shimano specifications at
file:///C:/Users/eggma/Downloads/2006_SPECIFICATION.pdf). I believe the above 45 and 50mm chainlines are the standard Shimano specs for road and MTB triples, respectively.
Bottom line, your FD may just not be able to extend quite out far enough. Don't believe you can use a shorter BB; what I am seeing is 113 is the shortest V2 Octalink available and if you could find something shorter your frame might not have room for the cranskset to move inward anyway If you like the gearing then try to find a FD that would work with your shifters and crankset. I am real happy using older Shimano MTB FDs (FD-M650/M735/M900) that work great with friction shifting (and Campy brifters that have "microsteps" for the FD) but don't know if they would work with Shimano road brifters. Good luck.
Thanks! Unfortunately the links you posted don't seem to work. This would make total sense as I was pretty sure I was using the minimum recommended BB length. As of now I'm unsure about the gearing. I suspect I need a smaller granny when fully loaded. I'm now looking into:
Outboard:
https://bike.shimano.com/en-EU/produ.../FC-T4060.html
Octalink:
https://bike.shimano.com/en-EU/produ.../FC-T4010.html
Square taper?
https://bike.shimano.com/en-EU/produ.../FC-T3010.html
As Cudak said above, the square taper might be the best option for touring. I'm just not sure if the Acera FC-T3010 are any good, or if they're even square taper. The on it's webpage the specs say it is but the image definitely looks like Octalink. Maybe they're just reusing imaging from an Octalink option they also sell.
The chainline on all of those crank options are also 50mm so it looks like I'd need a new FD no matter what I do. I guess I could upgrade the FD to a 50mm compatible one for now and change crankset when I've got a firmer idea of my needs. I'll look into the older Shimano FDs as you recommend for one that's 50mm compatible.