Front Derailleur
 

I want to change my front crankset to one that has 46 36 26 chainrings. I think I would eventually change the granny gear to 24 and possibly the large ring to 48. I am wondering what front derailleur will work with this range. I have done some research and know the Shimano XTR would work but it could cost more then the crankset. Would my Sora triple work??

- - I am not a bike mechanic but here is my experience for what its worth. My road bike originally had two chainrings 52 and 40. I changed it to 48 and 30. My LBS said the OE Suntour derailleur would not be able to guide the chain through the jump. So after some experimentation I used pliers to "modify" the cage on the derailleur and now it works great. Later the LBS owner told me he sees that alot: the owners manipulate the cage as needed to "improve" the performance. Maybe your Sora triple can be "influenced" to make it work.

For what it's worth.

....and I'm really wondering what BCD would allow that trick?

I used a regular shimano road triple FD witrh a 46/36/26 crankset.Worked fine. Think Rivendell does the same.

If you attempt to use a Shimano MTB front derailleur with the 46 36 26 combination, pay special attention to the Shimano specification for "minimum outer chainring / middle chainring capacity". It's a minimum of 12 teeth for all of the groups including XTR. I tried this combination while converting an old mountain bike into a commuter, and I quickly found out why they specify the 12 teeth. If you use 46 36 26 the inside plate of the derailleur will collide with the middle chainring as you attempt to shift to the outermost ring.

If the derailleur hanger is a braze-on type you may have a problem getting the derailleur low enough. If it is a clamp-on that shouldn't be a problem.

Good advice. As I look around for information I found that Rivendell uses their 105 triple front on mountain cranks. http://www.rivbike.com/webalog/shift...urs/17082.html

They say it should be adjusted to just clear the chainstay when it is in the granny gear. Why do I have a hard time picturing this?

Thanks for everyones advice.