What MTB front derailleur that will work with Shimano road STI le

[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.

[moobikes]

Have you tried using the XT FD you already have? It probably will work. If you are using a MTB crankset with MTB chainline, a road FD will have trouble shifting to the big chainring, if at all. I've set up a 6503 shifter with a M950 FD and it shifts well with a M950 triple crankset.

[Erik_A]

yes, I did try it, but the cable pull was way off - it took 2 shifts to go up one chainring. It was a newer XT Dyna-Sys; I wonder if the older XT 750/ 950 derailleurs have a cable pull closer to road...

[Gummee]

How bout a road triple derailleur?

M

[moobikes]

750/950 worked with my 6500 era shifters. Which shifters do you have?

yes, I did try it, but the cable pull was way off - it took 2 shifts to go up one chainring. It was a newer XT Dyna-Sys; I wonder if the older XT 750/ 950 derailleurs have a cable pull closer to road...

[Erik_A]

How bout a road triple derailleur?

M

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.

[Erik_A]

5700 triple shifter


750/950 worked with my 6500 era shifters. Which shifters do you have?

[dem]

For that combo (5700 + mountain crank + mountain FD) - you'd probably need a travel agent:
http://www.jtekengineering.com/shiftmate/shiftmate-7/

(no experience with your combination, but a fan of crazy drivetrains)

[Ed-B]

Shimano MTB front derailleurs typically have longer arms and lighter springs than STI road derailleurs.

So you might also try anchoring the front derailleur cable on the side of the bolt closer to the pivot, effectively shortening the lever arm and reducing the amount of cable pull required to move the mechanism.

[Erik_A]

Thanks! I will try.

I was also wondering if the older SunTour MTB derailleurs have a more "road" like cable pull.

[vitaly66]

Shimano CX70 front derailleur should work. I'm shifting a triple road crank with it (48/36/26), smooth, no problems.

[Erik_A]

Awesome, I will try that!

Shimano CX70 front derailleur should work. I'm shifting a triple road crank with it (48/36/26), smooth, no problems.

[vitaly66]

Awesome, I will try that!

You may glean some additional information here, noting especially the comments section:

https://janheine.wordpress.com/2013/03/25/trouble-with-sti-triples/

[Erik_A]

Those comments are a great resource - Thanks!

You may glean some additional information here, noting especially the comments section:

https://janheine.wordpress.com/2013/03/25/trouble-with-sti-triples/

[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 (thanks to ED-B 's advice).

More info can be found her describing this feat of engineering genius:
http://velobase.com/ViewComponent.aspx?ID=857c95e7-3c2a-4fd8-b5f8-6faaf1ae84bf&Enum=113

[vitaly66]

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 (thanks to ED-B 's advice).


Glad to know you got this sorted!

Can you say what derailleurs you tried that didn't work?

[TheseGoTo11]

Good stuff. I've got two drop-bar MTB setups and always like to hear how others are making the shifting work. FWIW, I can vouch for the JTek Shiftmate--handy little piece of kit. I'm using it with an Ultegra 6703 shifter and XT M770 FD and crankset. Shifts flawlessly.