Installing a nos deore dx fd last night. I was using a diy shim bc the clamp was 31.8 and the seat tube was 28.6, so I wanted to make sure i got it on tight. after tightening all i could i realized it was too low, started loosening it and the bolt snapped.
1)was the bolt just weak or are there other reasons this happens?
2)how do I get the little nut that is somewhat embedded in the derailleur arm out?
too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Originally Posted by Chris Chicago
.... so I wanted to make sure i got it on tight.
You probably overtightened it setting up the fracture. It's likely your shim was off size a bit causing you to feel you need more hold than it was designed for. Check dimensions carefully when you next install it (the shim has to be very close to 1/16") and if you feel you need more hold, use a tacking agent like the stuff 3m makes for light hold Post-it notes (comes in a stick), or carbon assembly paste.
The nut system is designed with exactly your problem in mind, just set a small punch against it through the clamp and tap it out the back. Odds you can remove what's left of the screw once it's out. You have a choice of buying an original screw, or using one made for water bottle bosses, or any stainless steel 5x.8 metric screw available at the hardware store.