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What is compatible with the older Shimano Tiagra FD-4403 9 speed triple derailleur

30/42/52 tooth chhainrings

34.9mm clamp on mount.

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Really most any Shimano triple road front derailleur for 8, 9 or 10 speed will work. Either one that comes with a 31.8mm clamp band or a braze-on type front derailleur can be used with a braze-on adapter, which is a clamp band that will accept the braze-on type derailleur if the bike lacks a braze-on mount. The adapter clamp band will obviously have to be a 31.8 diameter as well. These are quite common and easy to find.

The reason any of these speed classes of derailleur will work is that there was a consistent design in road front derailleur's that allowed for consistent derailleur movement based on shifter input throughout the speed classes. Essentially, a road "x-speed" front derailleur is more of a marketing term than a descriptor of the derailleur's spec so many different options over several years are viable replacements. This coupled with the fact that chainwheel size for road bikes remained consistent throughout those speed generations--most road triple cranks came spec'd with 52 or 53 tooth large chainrings prior to the compact sizing seen today. This is relevant because for good front shifting and minimal chain rub, the outer plate of a front derailleur should fairly well match the outer circumference of the large chainwheel. That's something to watch out for in the replacement but you'll find ones fitting a 52 or 3 tooth chainwheel far more prevalent.

Here is a line-up chart from the era of the FD-4403. Model numbers FD-6603, 5603, 4403, 2203, etc would all handle a triple crank with a 52 tooth large ring. Note the presence of the "3" in the final model number place. This is Shimano's convention that means it is designed for a triple front crankset as opposed to model numbers terminating in "00" (most common) or "02" (rarely) which infers a derailleur designed for a double crankset. Avoid these as a double front derailleur's cage is not designed to handle the range of chainwheel sizes found on a triple crankset. They can be set-up to work on a triple, but why? when the proper design is readily available.

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  • I'll defer to @Nathan Knutson 's excellent point about the large to mid ring tooth difference being a gotcha for a working replacement. While I haven't seen this as a problem in my more limited experience, I can tell you that for best shifting, the front derailleur's cage should be as close as possible to the teeth of the large chainring without interfering. Any set-up that forces the mounting of the FD to be higher away from the teeth is less than optimal.
    – Jeff
    Sep 11, 2021 at 5:50
  • Thank You Very Much for the information
    – Deb
    Sep 11, 2021 at 13:33
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It seems like an innocent question, but the situation can be maddening when a replacement FD is needed for any of the 30-42-52 cranks.

Front derailleurs have a spec that has been called by Shimano both "Min. difference between top and intermediate" and "Applicable top-mid tooth difference". It is the minimum difference in tooth count between the middle and large ring that the front derailleur can accommodate without the tail end of it bonking into the middle ring as it passes over, unless you make it much higher than you'd want to. For a long time, basically since the era of 9-speed front derailleurs that 4403 belongs to, Shimano changed to 30-39-50 for the road triples and the number for that spec is 11, whereas you need it to be 10. Being off by one forces the FD to be mounted much higher than optimal and it usually works poorly and can cause problems with derailment.

The good answers are any of the old Shimano 9-speed road triples where that spec is 10t, so FD-4403, 5503, 5504, 6503, and R443, in either the 34.9 clamp version if they came in one or in braze-on version plus an adapter. There have been a few repair type models that meet this compatibility too, such as Microshift R539 in braze-on configuration. That one appears to still be obtainable new, and I don't know if that can be said for any other compatible matches.

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  • Thank You Guys I really appreciate your input 👍
    – Deb
    Sep 11, 2021 at 13:34

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