Charlie Whiskey

I'm having a hard time finding a suitable front derailluer that will...

- work with a 9-speed Shimano STI shifter (specifically Sora 3503)
- can shift a 26-36-48 chainset with a 50mm chainline
- can be mounted on a 34.9mm external diameter seat tube

Closest I found is the Alpina-D but it specifies a 45mm chainline and I'm not sure that will work.

Does such an FD exist?

Alternatively is it possible to extend the FD out by 5mm or shorten the chainline by 5mm?

fietsbob

tried getting the help of your local Bike shop ? they have an incentive to get it to sell to you.

chain line is relative to the rear cluster .. center .. If OCD the 5 mm will matter. or not.

mconlonx

Get the Alpina, set it up, see if it works. I think it will...

Chris_W

Can you modify the chainline at all to reduce it by a couple mm?

If it is a Shimano crank with HTII external bearings, then there are probably one or two 2mm spacers behind the driveside cup. Remove one, reinstall the crank, and the plastic preload bolt on the left side should still tighten down just fine without bottoming out. This will cause a 2mm difference in lateral spacing of the pedals, which I doubt you'll notice, but if you are concerned then just move the cleats in your shoe by 1mm on each side to compensate. Making a road FD work with a 48mm chainline might be doable, whereas the 50mm probably isn't. If it is a square taper crank, then obviously using a shorter axle is easy.

dr1445

not sure how the shimano deore fd-m591 would play with the sora shifters. it is 9 speed, 34.9mm mount, 50mm cl and works with 48t triples.

nfmisso

Unfortunately; not well.