Bicycle Mechanics - Shimano 105 10-speed front derailleur with 9-speed everything else?

Hello-

Will a 2010 10-speed 105 FD be compatible with a 2001 105 drivetrain and brifters? Shimano redesigned the derailleur for 10-speed, and I am wondering how well it will work with a 9-speed chain.

Are they for the same size chainrings? Other than that I don't see why it wouldn't work other than the chain possibly rubbing on the cage a little more easily because the 10-speed has a skinnier FD cage. Why not just get the 9-speed though?

9-speed is getting tough to find new. 10-speed is easy to find, and I'm impatient to get my drivetrain swapped over to my new frame (with a different sized seat tube.)

Is it a double or a triple crankset? If triple you should try really hard to find a triple 9-speed or 8-speed.
If double then a 10-speed will work but a 9-speed would be better, as explained in the previous post.

It's a double. I'm going to give the 10-speed a go, since I can't find a 105 or better 9-speed in a 34.9 clamp diameter anywhere. Hopefully the plates aren't that much closer in the 10-speed design.

Tiagra is 9-speed. I expect that current Tiagra stuff is not much worse or the same quality as the 2001 105 stuff that it's replacing. I'd therefore go with a new Tiagra FD.

I am doing exactly what you were thinking of: a 105 10-speed front derailleur and everything else is Ultegra 9-speed circa 2001. The derailleur changes chainrings flawlessly, but it rubs and chatters in way too many gear combinations, about 1:6-9 and 2:1-4. My LBS heroically tried to make it work, but I think the cage is just to narrow. The noise is maddening, and it is unavoidable in the gearing that I use for a long 1-2% uphill grade, and/or a flat grade in a headwind, in the city, or when I'm pooped. It's also a big psychological downer to have noise/function issues with 1/3 of your gears.

Get a 9-speed front derailleur, is my strong recommendation. I am.

Well, I'm using a 10-speed 105 triple front derailleur on an 8-speed bike and it runs perfectly. However, my front shifter is friction so i can trim it at will. With index front shifting I doubt it would be so cooperative. :)

just spread the cage a bit, then it'll be 9sp width.

Buy the braze-on version here: http://www.bicyclebuys.com/drivetrain/DeraillFront/1010131PART and add a 34.9/35mm adapter clamp like this: http://www.bicyclebuys.com/drivetrain/DeraillFront/1010137PART

The beauty of this set up is a new frame will require at most a new adapter clamp.

Buy the braze-on version here: http://www.bicyclebuys.com/drivetrain/DeraillFront/1010131PART and add a 34.9/35mm adapter clamp like this: http://www.bicyclebuys.com/drivetrain/DeraillFront/1010137PART

The beauty of this set up is a new frame will require at most a new adapter clamp.
I'm a big fan of braze-on type front derailleurs and suitable diameter adapter clamps. For a given bike the clamp is a one-time purchase and braze-on derailleurs are less expensive than their clamp-on versions.

I forget who first pointed this out to me (someone on these forums, might have been you HR) but I'll likely never again buy a clamp-on road front derailler.