Originally Posted by sydney
You might want to check with Trek and give them all this info. They may offer different hangers,and yours could have been switched out. I wouldn't trust LBS idiots to have the full story. There are plenty of folks running compacts on OCLV,and trek even offers one.
Mine was originally switched out from a 7700 DA to a 6500 Ultegra by the previous owner.
Went to the local Trek dealer here in Portland and found out that the seat tube on the 5500 is 39 mm - too thick for a clamp-on. I was reminded that the tube has a flat indent where the der connects and thus would hinder a clamp from seating properly. I'll contact Trek directly and see what they can do. I'm wondering if this is specific only to the Ultegra 9 derailleur and if going to the new 6600 version or back to a 7700 (or 7800) DA would correct that. I was hoping not to have to buy a new der but....
The other options are to file the slot or have a hanger custom made.
55/Rad