Shimano FD - What is diff between Triple and Double?
 

1. Is there a way to determine if the FD is a double or triple before installation?
2. Can I use a double FD if I am willing to forgo shifting into my big or small chain ring? (my cassette is 11-34)
3. Should I use the correct sized 105 FD instead of using the Ultegra FD with an adapter (I am pretty sure I remember having one)?
4. Or is a FD likely to be able to be "restored" by cleaning and adjustment?
   • Mine usually doesn't shift into the big cog, and the shifts are imprecise - I need to click 2-4 times from the small cog and maybe click down).
   • I have not adjusted it in a year, it is caked with road debris
5. Is it OK to replace my chain with one that is one link sorter? I never ride in the big 53 cog with the 34-tooth gear.

HISTORY

• I have a 2007 S Roubaix triple 10-speed w/ almost all Ultegra.
• I am replacing my RD and I decided to replace the FD also.
• I have 2 Shimano FD's I picked up over the years, and I think they are both doubles, although that surprises me.
  • The mystery one is sealed in an OEM (?) plastic bag, labeled FTD0205-156 - 2 years ago, I deduced this was a FD 6600 34.9 Glossy Gray - and I wrote "double?"
  • The other is in a box for 105 and labeled SH-FD5700C-31.8

Thanks, as always.

It is extremely unwise to run a chain which cannot comfortably shift into the big chainwheel/big cog combination; you risk derailleur or frame damage. Even if you do not intend to shift into that combination you may forget, and when you do it will be too late. Running a too-short chain is rarely a solution to shifting troubles but is a good way to create some.
Whether you can remove a link depends upon how much excess length you have.
As to cleaning/lubricating your derailleur, it couldn't hurt and may help; perhaps you should examine your cables (they may be dirty too), especially inside your brifters for fraying, and housings. New cables can often make a startling difference in shifting performance.

1. The triple FD is much uglier with a double contour shape for each shift. This is specific to indexing. Before indexing they were all like the doubles.

https://i.pinimg.com/originals/bd/b8...f188431ccc.jpg

https://www.rei.com/media/2c0e5743-0...6?size=784x588

2. Big to middle might work, middle to bottom more likely a problem
3. The problem is only that the finish won't match
4. Yeah, pretty likely, and this might be a shifter or cable problem not a FD problem
5. Maybe, but why?

Nevermind.

John

If I recall, front needs more room to travel to get the chain onto/off all the rings. The derailer is only part of the system, the shifter needs to pull/release cable and have appropriate trim positions. It’s actually easier to make a derailer fudge the shift, impossible to make a 2x shifter do it. I would not bother with the effort, front derailers are cheap, I’d just get a new one

FD wear can cause poor shifting. If there's significant play in the pivot points that means it may need to be replaced. It's also possible for the cage to get deformed in such a way that it shifts worse. That said, they need replacing very infrequently and poor adjustment, grit in the pivots, cable friction, wear to the chainrings, and a malfunctioning shifter are all more common sources of poor front shift performance, in that approximate order.

Don't put a double FD on your bike; it will shift like garbage. The cage plates are shaped completely differently.

It is beyond idiotic to run a chain so short that you cannot shift into the big/big. You WILL do so at some point and it will explode. Also it will shift worse the rest of the time. It is also routine for professional mechanics to run through every possible gear combo, even the inadvisable ones..and exploded derailleur.

Thank you all. I do listen.

1. The cable IS stiff and I will replace it. I just did that for my RD last week - I managed to snake it into the housing without unwrapping the handlebars.
2. After lots of Carb cleaner, the old FD moves freely and the pivots don't seem sloppy. Plus it's had very little use - on most rides, I never shift out of the 43 cog (11-34 in the rear!).
   • But the H & L screws are frozen - I hit it with PB Blaster, hit the housing to create vibrations, and it is now soaking. Previously I had "adjusted the limit" on the small (H?) cog using the barrel adjuster. It has been frozen for a long time.
   • I will buy a new one if I can't get it to work. I's like the option to pedal when I'm going faster than 28 MPH (even though that's rare now in my 70's).
3. And I will add the missing link to the chain before using it. For now, I am using another new chain I had on hand.

So thanks.

FWIW the top FD pictured with the large vertical expanse of the back plate was developed for the 52/39/30 triples. If used on
52/42/30 triples it would catch on the 42 when upshifting to the 52, but clears the 39t ok. The earliest triple FDs in the
modern era were closer to the short vertical expanse of the second RD pictured.

Look at the part number. most will XX03 part numbers for triples. this includes cranks, FD, and shifters

I cannot find part number on any of them

If the PN's given above are correct, you already have the PN's, if the derailleurs are 6600 and 5700. If they were triples they would be 6603 and 5703.

John

The part and model numbers for Shimano front derailleurs are engraved on the inner cage plate on the side facing the frame. The lettering is small so look closely.

As mentioned, most Shimano triple components have an XX03 part number, e.g., a 10-speed 105 triple will be FD-5703 while the double would be FD-5700. FWIW, the 105 10-speed triple FD (FD-5703) is still available on-line from Amazon among others.