seriouslysilly

Hello,
Will the Ultegra FD6603 triple front derailleur work on a 9-speed?
Site says it's for a 10-speed, but was wondering if this will work on my 9-speed setup.
Thanks!

khuon

It'll work. However, the Shimano 10sp compatible (tuned?) FDs use a slightly narrower profiled cage. You can run a 9sp chain on them but expect a little bit more finickiness when it comes to rubbing as the 9sp chain is slightly wider. You'll probably be making a lot more trim adjustments than you would with a 9sp profiled FD's cage.

Al1943

The Ultegra 10-speed triple has 52-39-30 chainrings, the front derailleur is designed for that combination, another reason that it may not work well with your crankset.
The 9-speed triple derailleurs (other than D-A) seem to work well with 10-speed cranksets, but the reverse does not seem to work as well. YMMV.

Al

khuon

Good point but the OP did not mention what type of crankset they were going to use with the FD. And while it's true that the 9sp compatible FC-6503 comes standard with a 52/42/30, the curvature of the cage profile in front derailleur designs is really optimised for the big ring which is the same.

Al1943

True but the curvature is not as important as the difference in chainring sizes and the depth of the inside rail. ie. 52 to 42 is a 10 tooth drop, a D-A triple goes from 53 to 39, a 14 tooth drop.

seriouslysilly

thanks for clarifying that. i actually though the opposite

I am currently upgrading a 105 system to an ultegra gradually.
I have an ultegra triple crankset and using a 105 FD. everything else is still 105 (shifters, RD).
maybe i'll just hold out on a FD-6503 if that is the best option.
but then it would have been nice to have the option to switch to a 10-speed later down the road and already have the 10-speed FD. all i would have to swap are the cassettes, RD, and shifter.

Al1943

If you currently have a 105 triple front derailleur just stick with that, not much reason to upgrade to 9-speed Ultegra. When you are ready for 10-speed, upgrade the shifters, cassette, and chain simultaneously. You can upgrade the other components later if you need to. I would not spend any real money on 9-speed now.

seriouslysilly

i wish i could stick with it since there's really nothing wrong with the 105. it's just that i'm going to swap all the components into a new frame. The current frame uses a 28.6 clamp and the new one needs a 32mm clamp.
i don't know if i can just get swap the clamps and use the same FD or have to get a new FD

khuon

The outer to middle difference is not important with regards to a FD's capacity. The difference between the outer to inner is what matters. And in this case (52/42/30 vs 52/39/30), that difference is the same (52 - 30 = 22).

khuon

Unfortunately, you cannot replace the clamp on the FD-5503. Newer Shimano FDs use a multi-clamp design though and will fit 28.6 as well as 31.8 diameters. A new FD-6603 is around $50 and will work fine with your setup.

Al1943

And I wasn't talking about capacity, it's the geometry of the derailleur that is important. If you'll read my message it's the depth of the inside rail that's designed for the differences in chainring sizes. Sheldon Brown and others have mentioned this in posts here. Capacity is a completely separate issue.

khuon

Ah... you're talking about front difference. Yes, that might be an issue but at least on paper it should be okay. According to the spec-sheet, the FD-6603 has a 13T limit. Assuming the OP's cranks are the more common form of the FC-6503 which came as 52/42/30 then it's within spec of the FD-6603. Or are you saying that the 10T difference is not enough?

Al1943

What I'm saying is the Shimano (other than D-A) 9-speed triple FD is designed for 52-42-30 rings (10 tooth drop big-middle) the 10-speed Ultegra FD is designed for 52-39-30 rings (13 tooth drop).
I guess I was too brief in my first post, I was agreeing with you that there should be a concern for the narrower cage, and that may be the more important issue, but that I would also be concerned with the other derailleur design changes that Shimano has made to fit the new chainring sizes. Based on posts that other forum users have made, the new triple front derailleurs are not really backwards compatible.
An additional issue may be that the 10-speed D-A, Ultegra, and 105 triples have specifically different chainring sizes. With 9-speeds only the D-A is different.

khuon

Hmm... so you're saying the FD-6603 cage length was designed with a 13T minimum drop from the big ring. I suppose if a cage made to really closely match a 39 had too much length, it wouldn't clear a 42 when shifting to the 52. I guess adjusting it high might be the only option in such a case but that of course exposes other problems.