5

FD-3400 spring seems to have given up the ghost, I have tried cleaning all the joints etc but the spring just doesn't have enough power when the cable is completely slack to pull back the derailleur.

This being an old part I can see I might get one second hand but new seems unlikely but I cannot make much sense of if a newer model would work.

I have the version that has a clamp around the frame (not part of the derailleur) and the derailleur screws into this clamp. Again I couldn't work out from the descriptions what this kind of fitting is refereed to.

thanks for any help

ADDED PHOTOS

enter image description here enter image description here enter image description here

Brian Norman
  • 51
  • 2
  • 1
    Pictures of your derailleur and it's mount would help ensure there's no ambiguity in determining a proper replacement. – Andrew Henle Nov 27 '21 at 13:14
  • Thanks @AndrewHenle added to original post – Brian Norman Nov 27 '21 at 13:32
  • 2
    Not worth a full answer, but if you need a replacement, you can look for a braze on FD. You could also get a clamp on in the same seat diameter as your frame, which I’ll guess is 31.8mm (check manufacturer specs to confirm if you can) – Weiwen Ng Nov 27 '21 at 14:40
  • 2
    I'd also expect any double/dual-chainring front derailleur from the 7700, 7800, 7900, 6500, 6600, 6700, 5500, 5600, 5700, 4400, 4500, 4600, 3300, 3400, 3500, 2200, or 2300 series would work (pretty much the entire set of post-1999/2000 and pre-11 speed/~2013ish Shimano road line), but I'll defer to those here who have more in-depth knowledge of that. – Andrew Henle Nov 27 '21 at 14:52

2 Answers2

4

I believe that your Sora derailleur is an 8-speed part (please correct if wrong).

That being the case, the correct new replacement is a Shimano Claris FD-R2000 (braze-on mount), but the new cable ratio means you will have some slack cable when the derailleur is in the low position.

However, you should be able to find any of the early 90s derailleurs at online auction for a reasonable price that could include Shimano 600 (FD-R6400), similar era 105, Shimano RX-100 or even a newer Shimano Claris FD-2400 or FD-2300.

As you have indicated it's a 9-speed part, probably worth searching for a 9-speed derailleur. The cage is very slightly narrower for the narrower 9-speed chain. These historical part numbers on the used market would be Ultegra FD-6500, 105 FD-5500, Tiagra FD-4500 etc.

Nathan raises a point about chainring size compatibility but this is a non-issue unless your frame has abnormal geometry; all the above are rated for the 16-tooth jump between the two rings and will work better than the Sora derailleur when in good condition.

Having the band-braze on adapteris a benefit as it makes selecting a new part straightforward. I'm surprised more shops don't just stock Braze on type front derailleurs and keep a variety of band adaptors as it saves quite alot on inventory!

Noise
  • 13,943
  • 1
  • 14
  • 46
  • 1
    Are you sure about cable pull being an issue here? I thought this only applied to the RD. Also, in the low position, wouldn’t both derailleurs be in the same position? If cable pull ratios were different, then the new FD would either experience too much or too little cable pull in the high position. – Weiwen Ng Nov 27 '21 at 13:47
  • 1
    Rear is 9 speed, not 8, not sure what difference that would make to the front? – Brian Norman Nov 27 '21 at 14:04
  • 1
    @WeiwenNg Generally, front derailleurs can be hacked, but some (eg. Shimano 11s) have exceptionally different cable pulls which can be utterly incompatible with other shifters regardless of hacks. Same position in the low gear, yes. If the new der would have too much cable pull in the high position, you set it so there is slack in the low so it arrives at the correct high. – MaplePanda Nov 28 '21 at 05:45
  • @WeiwenNg The cable pull ratio indeed changed recently. The compatibility chart https://productinfo.shimano.com/download/pdf/com/3.2/en shows. 2300,2400 vs. R2000 resp. 3500 vs. R3000 on separate branches for front shifters/derailleurs. They are compatible in the rear. – Vladimir F Героям слава Nov 29 '21 at 19:39
  • The mainstay 9-speed era Shimano road front derailleurs (5500, 6500, 7700) aren't rated for compact. Mainstream compact doubles didn't exist then and the manuals call out jumps of 15t or less. Yes it can be made to work in most cases, but in my recollection things got smoother once the front derailleurs were designed with 34-50 in mind. – Nathan Knutson Nov 30 '21 at 19:15
3

Your old derailleur is a braze-on type, and the thing that says "Superleggero" on it is a braze-on adapter. Most road bikes with braze-on adapters are also capable of having a band clamp FD mounted also, but there are some out there where the reason for the adapter is a non-standard seat tube diameter, so that's the thing to check. The standard sizes are 28.6, 31.8, and 34.9mm.

Shimano has switched to their "long-arm" design for new Sora, the current FD-R3000. The long arm designs expect less cable pull coming in, matched by the current Sora STIs. I don't have a wealth of experience mismatching the new FDs to the old shifters, but as JoeK points out, conceptually you should be able to do it on a double by starting it with the right amount of cable slack. You may find the feel at the shifter to be kind of wonky if you do it this way. It will start out moving with no resistance, then it will hit the point where the FD begins moving and there will be a ton of resistance since the shifter is pulling a lot of cable per hand input and so the mechanical advantage relationship is opposite from how you'd want it, and then the FD will get into the more easy-moving part of its actuation curve.

Shimano often produces something that can be used as legacy support part for a long time in these situations even when the current groups have moved on with their compatibilities. FD-3500, the derailleur I'm about to recommend, played that role at one time for old 9-speed road groups. They currently don't have something like this in production for a 9-speed compact-friendly road FD it appears, but Shimano is very oblique usually about why or whether that's a permanent or temporary situation.

Your easy choices are get a third-party replacement still made new or get a used or new old stock compatible Shimano FD.

  • Shimano FD-3500-F would drop in with what you have. The Shimano FD models that end with -F are the braze-on versions, and -B is band clamp, but again you need to measure what you have and look up what you're getting to make sure they actually would go together if you went that route.
  • The Microshift R9 in braze-on (FD-R352-F) is a currently produced third party replacement that would also work here. Microshift is okay quality.

Be prepared to need a new cable whichever way you go in case there are differences in length needed.

Don't get a different speed generation FD than the 9 you need.

If you tried using various of the pre-compact 9-speed double FDs (which is most of them), they would mostly work but there may be some surprises out there with the top to bottom cage size or the chain contact points not being what they need to be. Since you have the ability to get something made to play nice with compact, it's better to just do that.

Nathan Knutson
  • 84,914
  • 3
  • 90
  • 214