kommisar

I have a old road frame with a newly installed 44T big ring double crank. My old front derailleur was designed to work with a 53T big ring and I cannot move it low enough on the braze on to get close to the new 44T chain ring. I thought a clamp on might work but the seat tube flairs out below the braze on. Does anyone know of a braze on FD that works with a 44T ring?

JohnDThompson 

If the problem is that the derailleur mount is too high for your preferred chainring, perhaps something like this might work:


https://www.wickwerks.com/products/fit-link-adapter/

Hondo6

More info would be helpful, and is probably necessary.

1. Make/model of existing FD.
2. Make/model of existing front shifter (road and mountain indexed front shifters reputedly have different pull ratios). From your description, I'd guess you have a road FD and shifter - but we don't know at this point.
3. Make/model of frame and/or bike.
4. Distance from bottom bracket center to center of braze-on mount hole/slot.

Pictures would also help immensely.

The last dimension is needed because a FD will almost always need to be raised/lowered from its existing position to use a different largest chainring. Given that dimension, it might be possible for someone here to calculate how low your FD needs to be to use a 44T chainring (no guarantee on that). Since you have a braze on fitting, depending on its configuration and type that will limit how low you can lower a given braze-on FD (this is one place where a picture would be especially helpful).

I'm probably missing something. But remote diagnosis needs all the info it can get.

Hondo6

I was composing while you were posting, JDT. Bu that might be just what the OP needs, provided his existing FD will work acceptably with a 44T largest chainring. And he may need it anyway if he replaces his existing FD.

Ross200

IRD SubC or Shimano CX are for smaller chainrings and might work with the current braze on mount. With the drop mount for sure.

Is the rear derailleur cable over or under the BB? Many "full sized" FD will foul the cable if it is on top. Creative mods to the cage are always possible.

Andrew R Stewart 

One issue with ft ders that are intended for 50+ T rings and used with much smaller rings is that the cage's lower edges have a fairly large curvature, to best match up with the larger ring's circumference. hen used with smaller rings the ring to cage gap grows significantly as you go from the cage ft tip to the cage tail. This is why I run MtB based ft ders on most of my bikes (that have 44 or 46T large rings).

Unfortunately the imaged adaptor will further locate the cage from the smaller ring's tooth tips allowing for more chain flex and thus likely resulting in more sluggish shifting.

One more cost to having a bike with a brazed on ft der Andy (who has only built a few frames with braze on ft der mounts and those were when working dor another builder, many many years ago)

kommisar

1. ~1996 Campy Chorus FD
2. Front shifter will be a friction bar end
3. Frame is 1990 schwinn paramount OS
4. ~149mm

kommisar

rear d cable runs under the bb

rccardr 

This may sound like a strange idea, but it looks like you are using a triple as a compact double, essentially running only the middle and granny chainrings. If so, then using the same kind of FD as you would use on a triple (not sure if that is what is pictured, not a Campagnolo expert) should result in the same kind of shifting quality. In other words, just like shifting from the middle ring to the granny. Not an optimal solution, but wouldn’t this work?

Hondo6

That photo's pretty telling. If the large chainring in that photo is 44T, I'd guess you're going to need a "dropper bolt" of the type about which JohnDThompson posted photos and links above to use that FD (and possibly to use any braze-on FD) with a 44T largest chainring on that frame. In the photo that FD is at the lower limit of the braze-on frame fitting and still appears too high.

I couldn't easily find the relevant specs re: min largest chainring size supported for your Campagnolo FD, so I'm guessing that may also be a potential problem. (The specs are probably out there, but I'm not at all familiar with Campagnolo equipment or where to find their specs; that's probably why I couldn't find them.) As Andrew R Stewart noted above, you may run into problems with that FD if you're using it with a much smaller chainring than it was originally designed to support.

Friction shifting for the front means you don't need to worry about indexing incompatibility for the FD and shifters. There are many FDs out there that work with smaller front chainrings in the 44T range, mostly MTB FDs. But as noted above, I'd guess that for most of those that are dual- or bottom-pull you'll also need the dropper bolt.

The suggestion by rccardr to use a triple FD (Campagnolo made a few) would IMO also work. In that scenario you could also install the outer chainring, set it up as a triple with a 44T middle chainring, and only use the largest chainring on level ground if at all. Aesthetically it would be the nicest solution IMO. But that scenario (triple FD, triple chainring) might well require a different BB or spindle length to get the proper chainline.

Your bike, so your call. Best of luck.

JohnDThompson 

I'm not a fan of permanent, aka "braze-on," front derailleur mounts, either, but there are situations where they are needed, e.g. non-round tubing for which a clamp mount cannot work. In situations like that, you are limited to the chainring range the builder/designer had in mind in placing the mount, or be willing to accept a compromise solution like the adaptor above, or a 1x drivetrain.

dedhed

Is there room to fit a clamp on adapter below it?

​​​​​​https://problemsolversbike.com/produ..._clamps_-_6321

kommisar

Unfortunately the paramount OS flairs the seat tube below the mount so a clamp is not going to be useable. On the bright side, a hard standing climb will not cause a ghost shift with this frame.

base2 

I've never been a fan of E-type derailleurs. But this may be a case where one could work.

Something like this:
https://m.pinkbike.com/product/shima...nt-Derailleur/

kommisar

Oh, this looks promissing! Coming from below instead of from above. Does the frame / bb have to have anything special to use one of these?

Atlas Shrugged

Or order a Wickwerks adapter, as was mentioned at the beginning and be done with it.

base2 

The WickWerx adaptor is probably the more elegant solution.

The E-type simply mounts between the bottom bracket and the frame. The e-type bracket is the same 2.5mm thickness as a spacer that a standard 73mm bottom bracket would use to fit a 68mm frame.

As to whether or not the derailleur is top pull/bottom pull or otherwise, I suppose it is up to the derailleur mounted to the bracket.

In my one & only experience with an e-type I had to figure out an effective stop for the cable housing because the bracket itself was flimsy. I would bank on a solution requiring full length housing all the way to the derailleur.

Here is my solution after remachining a new bracket from much stiffer 7075-T6 aluminum:
20190216_112708 by Richard Mozzarella, on Flickr
The derailleur was either top or bottom pull. But the frame had provisions for neither. In any case, as mentioned, the mounting bracket was too flimsy for my taste. So made my own, I drilled a hole suitable for an M5 bolt, then used a Travel Agent as a cable housing stop & the pulley to change the cable direction. It worked wonderfully.

kommisar

Thanks for all the information people, I learned of several new ways of making this work. You guys know a lot of stuff. Not sure what I'm going to do here but I'm on a money diet now through the holiday season so it looks like this upgrade wont happen until january.

SJX426 

@kommisar - Check this out Help me build a 1990 De Rosa Pro

kommisar

Ah I think I get what people were talking about up thread now. I am using a 32t inner and 44t middle chainring on a triple crank. These are approximately the size of a campy road triple (30t inner, 42t middle, 52t outer) so in theory a campy triple fd should work. Sometimes it takes me a while to see the obvious.

gearbasher

How about a Campy compact front derailleur. They're designed to work with 50/34 chainrings.

maddog34

Older Specialized FSR XC bikes (2001-2004, possibly others, and many of the Early Sp. Enduro bikes too) use a similar mount system and come set up for a 42 or 44T Derailleur height and correct chain ring curve... example pic... the der. is located to the seat tube with a half-round that sometimes has a plastic shoe that adapts to either 31.8 with shoe, or 34.9mm sans shoe... this particular one has the outboard locating screw tab too... Example pic... https://www.ebay.com/itm/25577019629...79c8d44e036ae4

Hondo6

Failing to see the obvious for a while happens to everyone - about once daily for me, it seems.

As I noted above, this solution also has the aesthetic advantage that you can install an outer chainring if you want and just never use it (or use it only on flats). There would be a small weight penalty, though (weight of large chainring and any necessary spacers). Your call.

I'll defer to our more experienced commenters regarding whether or not you'd need a different spindle length if you were installing the outer chainring for cosmetic purposes only and never used it. I think you would if you were planning to actually use it and wanted the bike to shift nicely, but that may be necessary anyway if you're using a triple crankset. (If it's a triple crank, you may already have the correct spindle length - or not, if it was installed later; dunno.) I'm not a Campagnolo user so I have zero practical knowledge of how sensitive their shifting is to chainline variance.

rccardr 

Only a triple sized spindle will give the OP sufficient clearance for the granny.
A shorter double sized spindle would not permit the granny to clear the chainstay.
The granny is already there and has clearance, ergo he is currently using a triple spindle.

Hondo6

Thanks, @rccardr. Don't use Campagnolo components, so I wasn't sure if that was the case or if it was a case of, "Yeah, it will physically fit - but it won't work worth a damn" with a double spindle. Thanks for the info.