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I bought a new frame and put my old Campagnolo Racing T components on it. The seat tube has a diameter of 35mm and I use the Campagnolo 35mm clamp for the Racing T derailleur.

The problem is the derailleur can't push the chain to the small gear because a part of the derailleur touches the seat tube.

Is the frame incompatible with a 3 speed crank or do I just need a compatible derailleur for frames with a wider seat tube, maybe the ATHENA Tripple?

Parts

  • Frame: BULLS Desert Falcon, Seat Tube 35mm
  • Crank: Campagnolo Athena 11s
  • Derailleur: Campagnolo Racing T
  • Bottom Bracket: Campagnolo BB90 Power Torque

Images:

  • Derailleur touching the frame: Derailleur touching the frame

  • Crank: Crank

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    I've never done it but I would think some type of spacer between the chainring and the BB could give you a bit more clearance to let the front derailleur push in further.
    – ebrohman
    May 28, 2015 at 20:15
  • I was thinking this too, or maybe twisting the derailleur a little to knock the chain earlier? The top picture looks like it is slightly twisted out compared to the outer sprocket, but can't tell for sure.
    – BillyNair
    May 31, 2015 at 23:46
  • The BB does not have enough offset.
    – Daniel R Hicks
    Jun 6, 2015 at 22:16

2 Answers 2

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The chainwheel does not sit at the correct chain line is the answer.

The most common cause is that you have an axle length shorter/longer than the ideal chain line. In this case, you have a shorter axle length.

Did you add another chainring into your crankset? If the answer is yes, you will need to tweak around: either adding spacer (not recommended) or find a compatible front derailleurs (better get to the LBS for trial/error fitting). If the answer is no, then it will be the frame that cause you the problems, albeit unlikely. I always solve this problems by finding a correct axle length for my crankset.

You can refer to this article for more information, from Lord Sheldon. http://www.sheldonbrown.com/chainline.html

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1

Replacing the Racing T derailleur with the Athena 11s derailleur fixed the issue. The racing T derailleur seams to don't work with the 35mm Campagnolo clamp. Or generally don't work with frames wider than 28mm.

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