Erik_A

I have a steel Singular Swift MTB that I am trying to set up with 3x10 speed Ultegra STI shifters (actually the left front is a 105 triple shifter).

The Singular has a 28.6 seat tube and I was using a direct-mount XT FD (down-pull) before I decided to switch to the drop bars.

what down-pull MTB front derailleur can I use that will work with Shimano road FD cable pull? Or maybe there is an alternate cable mounting work around. I tried using a road triple FD, but it wouldn't engage the big ring on the crank, because it didn't have enough reach.

Slash5

A cyclocross derailleur may work. I saw a thread where someone drilled a hole in the arm to reduce the travel. He routed the cable through the hole and then to the clamp.

rccardr 

CX 70 should work, will also be happy with a compact. Oops, saw it's a triple, only have experience with these on a double.

Erik_A

thanks!

Slash5

Depending on the crank setup you are using, you could move a drive side spacer to the non-drive side. Maybe the road derailleur would work then.

Erik_A

Thanks, I will try.

SkyDog75

As Slash kinda hinted, chainline might be part of the problem. Mountain triple cranksets tend to sit a little further out from the bike's centerline, so a road derailleur might have difficulty reaching the outer ring. According to Sheldon Brown, typical chainline for mountain bike triples is 47.5 to 50 mm. Shimano spec for road triples is 45 mm. (Chainline is measured from center of seat tube to the middle ring of a triple crankset.)

Do you have enough clearance between your inner chainring and chain stay to move the chainring in a few millimeters? If so, that may be the easiest fix, depending on what kind of crankset you're running.

Erik_A

Thanks, I will check and see if there is more room to squeeze inward.

Erik_A

Thanks, this blog and the comments are a great resource!

Eggman84

I understood that the current CX-70 front derailleur may have enough travel though it is listed for a double. Earlier versions of 2X Ultegra front derailleurs worked. I am using an FD-6500 and Ultegra 3X9 shifters (ST-6510) to shift a Tiagra triple crankset though the chainline on the Tiagra is only 145mm where that of a modern MTB crankset is normally 150mm.

This is part of the problem with modern cranksets with integrated spindles; you are stuck with the manufacturers chainline. With older 3 piece cranksets you could get different length bottom brackets to adjust the chainline to fit your bike and needs.

Erik_A

Well, after trying 3 or 4 front derailleurs, I finally found one that works like it was made for this application. A trusty 1989 Shimano FD-M732. Only modification is that I am running the cable on the outside of the bolt rather than on the inside and over that little ramp thingy as originally intended.

More info can be found her describing this feat of engineering genius:
VeloBase.com - Component: Shimano FD-M732, Deore XT

shelbyfv

Very cool. How did you know this existed, much less find one. Looks like it is 28.6 w/o a tacky shim! Great find!

Erik_A

I "found" it on a used 1989 Specialized Stumpjumper Team MTB that I disassembled.