Touring - trekking crank and front derailer

I am looking at building a bike with a XT Trekking crank (48-36-26) with a road bar setup. Since I plan on using the bike for some fast rides, I would like to stick with STI shifting; but I recall that road STI shifters will not work with MTB front derailers.

Is this still the case?

The crank ...

http://bike.shimano.com/catalog/cycle/products/component.jsp?PRODUCT%3C%3Eprd_id=845524441762862&FOLDER%3C%3Efolder_id=2534374302050390&ASSORTMENT%3C%3East_id=1408474395181674&bmUID=1184009580109

The Shimano recommended front derailer --> sized for a 48t big chain ring ...

http://bike.shimano.com/catalog/cycle/products/component.jsp?PRODUCT%3C%3Eprd_id=845524441762914&FOLDER%3C%3Efolder_id=2534374302050391&ASSORTMENT%3C%3East_id=1408474395181674&bmUID=1184009580109

The specs state that it can be both top and bottom swing. So it crossed my mind that it might be compatible. Although my fuzzy memory recalls that the road STI shifters pull a different amount of cable than the mountain shifters.

Is the best alternative a 105 road front derailer designed for a big chainring of 50t?

Any other suggestions?

Thanks for reading.

-G

I am looking at building a bike with a XT Trekking crank (48-36-26) with a road bar setup. Since I plan on using the bike for some fast rides, I would like to stick with STI shifting; but I recall that road STI shifters will not work with MTB front derailers.

Is this still the case?

The crank ...

http://bike.shimano.com/catalog/cycle/products/component.jsp?PRODUCT%3C%3Eprd_id=845524441762862&FOLDER%3C%3Efolder_id=2534374302050390&ASSORTMENT%3C%3East_id=1408474395181674&bmUID=1184009580109

The Shimano recommended front derailer --> sized for a 48t big chain ring ...

http://bike.shimano.com/catalog/cycle/products/component.jsp?PRODUCT%3C%3Eprd_id=845524441762914&FOLDER%3C%3Efolder_id=2534374302050391&ASSORTMENT%3C%3East_id=1408474395181674&bmUID=1184009580109

The specs state that it can be both top and bottom swing. So it crossed my mind that it might be compatible. Although my fuzzy memory recalls that the road STI shifters pull a different amount of cable than the mountain shifters.

Is the best alternative a 105 road front derailer designed for a big chainring of 50t?

Any other suggestions?

Thanks for reading.

-G

The crank isn't the problem. The derailer is. It's kinda a crap shoot as to whether or not the XT will work with STI. I've not be able to make them work. Go with a Tiagra triple on the front. It's actually a better derailer for road triples then its more expensive cousins. It's wider between the plates so it's more forgiving on chainline issues.

I'm running an XT trekking crank and a Ultregra triple front (first used on a 52 tooth 105 crank set) on my commuter bike with STI shifters without problems...other than a little rubbing:mad:

Check out the IRD Alpina front derailleur:

http://www.interlocracing.com/cdfrtder.html

I have a 105 FD installed now with the LX version of that crank (48T). 105 is only temporary while I was waiting on my LX FD to arrive. The 105 worked "sorta OK" but it was real sensitive to position and the chain still rubs a bit if you don't have a good chain line. I could live with it temporarily because I am using friction shift on the FD (bar end shifters on Paul Thumbies) and I can fine tune it as I go. I don't think you would like the 105 with STI on that crank.

That Alpine is a bit pricy at $50 for a FD.

Hmmmm, thanks for the input. I already have a Tiagra triple front derailer; so that would be used on the first pass. Although the Alpine is on the expensive side, sometimes it is worth the extra bucks to get the right "tool" for the job.

I have looked on the Shimano website for any hints. But no such luck. It crossed my mind to find road bikes with the 48-36-26 setup; but I have not found any in my brief search.

I'd stick with the Tiagra--- and make sure your have a good chainline. Lots of people blame the FD for a funky chainline. Funny what the right bottom bracket or a spacer can do for your shifting.

I'd stick with the Tiagra--- and make sure your have a good chainline. Lots of people blame the FD for a funky chainline. Funny what the right bottom bracket or a spacer can do for your shifting.

Good point.