I'm working on a late 1990s donor bike for our church's Bicycle Ministry. It's a vintage, rigid for, mountain bike. The original bottom bracket, a cartridge type, is toast. The objective is to repair these bikes with a minimum of cash outlay. So my plan is to replace the cartridge with a spindle type of which I have about a dozen in my spare parts bin. I should point out, this has an E type front derailer that mounts to the frame via the right side of the BB. The original BB is 113mm to fit a 68mm shell. So I found the smallest spindle I had, a 116mm and figure a little overhang on each side, no problem right? I was wrong. Two problems. First, the cup I chose went in so far that the lock ring had no threads to screw on to. So I replaced that cup with another that extended outward. Now I can get a purchase for the lock ring (barely) but when I torqued down the left crank arm, it hits the cup and won't turn. It appears the E type derailer that mounts on the right side of the BB is messing up my calculations. Before I go crazy trying different spindles and cups, is there something I'm missing here? Should I just throw in the towel and buy a cartridge type replacement?
I've successfully done this before, but never with an E type derailer. Any thoughts or suggestions appreciated.