Bacchetta Giro 26/20 chain idler
I have an early 2000s Bacchetta Giro 26/20 and have been hearing (and feeling through my feet) a nasty metal on metal screech when climbing steep hills. I'm not seeing any interference/contact with the front sprocket or front derailleur. I put it on the mag trainer and cranked up the resistance as far as I could and still turn the crank with my legs in the lowest gear, but have not been able to duplicate the problem. I think it's very likely the chain idler wheel, though, because it doesn't turn very freely by hand and the chain has worn deep grooves in the rubber part of the wheel. I know I have replaced this part before, but I think that was because it just fell apart. I don't remember any screeching the last time, but then my memory's kind of a sieve.
Anyway.... I think I should just go ahead and replace the dang idler wheel again, but when I looked for the part on the Bacchetta web site, the only one I found is a much larger diameter than the one that's on there now. I tried contacting Bacchetta via their website contact form a few weeks ago, but haven't heard back from them. So, I'm hoping someone who's in the know on this will tell me whether or not the newer, wider idler (wow, try saying that real fast a few times!) is the correct replacement part for my older, narrower one. Any thoughts, stories, etc. about diagnosing nasty squealy, screechy sounds in recumbent drive trains that anybody feels like sharing would be welcome as well.