Originally Posted by Expatriate
Climbo, it's a derailleur issue. Either the adjustment screw needs adjusting, or your derailleur may not offer enough swing for a triple. What shifter and derailleur are you using, and did this work before you replaced things?
I adjusted the screw way out so the der. goes way over to the inside but it still wouldn't drop off the 32. It's all Shimano XT stuff (shifetrs and der.). The derailleur oves quite a lot, it rubs the chain and tweaks it at a huge angle because it's all the way over and the chain is still on the 32 ring rubbing the derailleur plate.
Before I replaced it it was a singlespeed, I haven't put the triple on it for about 3 years. So, it has worked in the past but not with this set-up, it was all different years ago, I had to get a new front der and ring for the cranks before I could put it back on.