I have a 1987 Eddy Merckx Century frame. I'm installing campy chorus triple 10 speed crank (53/42/30 chainrings), and bought a centaur 10 speed triple braze on front der.

The problem is that the der. Cage does not clear the large chain ring even when set at the top of the braze-on slot. The overlap is approx. 4 mm. There is no way a little filing will create the room needed.

The der. Looks identical to the other braze on 10 speed front der I have seen.

Any ideas or suggestions?

Thank you in advance!

Andy

Is it possible you bought a derailleur made for compact drive, ie. 48t outer ring?

If you're not sure, remove the derailleur and compare the curvature of the outer cage plate to the 53t ring. If it touches at the ends and arcs away in the middle, the radius is smaller, so sounds like compact drive.

Compact cranks typically have a 50T big ring but the concept is right. Campy did make "compact specific" front derailleurs for a few years and that may well be what the OP has. Chorus triples were last offered about 2007 while Campy was still making those compact-specific fd's.

Incidentally, Shimano never produced compact-specific front derailleurs saying they were unnecessary. After a couple of years, Campy agreed and dropped them from their product line.

I'm using a triple on my Merck Century frame but it's a compact: 50/36/28. Shimano Ultegra 6600 triple FD clears it just fine, with a little room to spare. Not sure it would do the same with a 53.

Necessary is a matter of opinion which can change very quickly depending on the market and cost of producing more permutations of a product. Every tooth changes the radius of a chainring by about 1/12" so a 50t ring would come up about 1/4" lower than a 53t. Depending on the height of the braze on and length of it's slot, this can make for FD locating issues when changing rings.

There's also the issue of the curvature of the cage, Going to smaller rings is rarely a problem, but going to rings larger than those the FD is designed for can cause the heel to touch the ring while the front is well above the 2mm clearance target.

So while 50 or 53t may no be a problem, bigger changes, or using mtb FD with 53t rings can be.

1 tooth smaller chainring? TA does odd and even numbers

I own a race triple with a 52,42 combo so <C> ring can be bought.

I think the triple is 135-74, all 5 same bolt circle , so possible ..




(though <C> has a trick up their sleeve, compact crank, 1 bolt hole not in the same circle r as the other 4)

Actually road front derailleurs are remarkably tolerant of smaller-than-designed large chain rings. Years ago I bought my son a Trek 1220 which came with Shimano's 3x7 RSX triple group. The chainrings were 46/36/26 but the front derailleur was an RX-100, a 105 triple look alike, designed for a 52T large chainring. Despite the design differences, it shifted very well.

Going the other way, and neglecting the cable pull requirement differences, using an MTB fd intended for a 44T chainring on a road crank isn't nearly as successful. It's tight curvature requires it to sit too far above the bigger ring.

Yes, going smaller is rarely an issue, especially with clamp on FD which can be lowered as much as wanted. I should have been clearer that the limitations on going smaller apply to braze on FDs which often cannot be lowered enough for good shift response

Yes, we often hear about braze-on tabs that won't let the front derailleur lower enough. This is the first time I recall one not letting it go high enough.

Thank you for all the information. I fitted up a 52 tooth chainring and its closer. The cage is probably still a couple of mm away from clearing the big chain ring. The radius of the cage looks fine against the big chainring. I'm thinking this der. is for a compact crankset. I think a 50 tooth chainring would allow the cage to clear? If the der. says "racing triple" will it work with a 53 tooth outer chainring? Thanks again, Andy

Yes, it should. The Racing triple derailleurs were made for triples with 52t outer rings. They made the racing-T so they didn't have to make both Chorus and Record versions of this niche derailleur.

BTW- it you're looking to buy one, send me a PM. I have a few left still new in box from 2001 or so.

Thank you again for the help. I cannot PM you because I have posted enough.... Yes, I'm looking for a racing triple.

Are you sure you have the correct bottom bracket? If your chainrings are too close to the frame it could be a problem as the FD moves up as it moves out.

FWIW, I'm running 10 speed Campy chorus with a Veloce Comp Triple FD (braze-on). Chain rings are 53/39/26. This shifts extremely well, better than the Ultegra triple FD. If you can stick with a Campy FD. The actuation arm length and angle appear to be different and better match to Campy shifters. I'm even shifting a quad setup on our daVinci with the same shifters and FD. Our course my largest chain ring is only 30t.

From the continued web surfing research, it look like the front der. I have is the same as the race triple version. I have been told by others that campy didn't make a compact specific triple? I have had the frame for over 10 years and have been using a centaur double front on a 10 speed 53/39 chorus crank with no problems. I'm told campy published a table explaining front der. braze on height with compatible chain rings. The triple chorus 10 speed crank and bb are the right match. Not sure what else to do except possibly explore buying smaller chain rings?