I picked up a used 2006 Trek 520 for pretty cheap as a project bike. This bike: https://archive.trekbikes.com/us/en/2006/trek/520#/us/en/2006/trek/520/details (specs are on that page).
I took it completely apart to get rid of some light rust in the frame and am going to get it powder coated. Once that's done I want to change the front chain rings but I'm not sure what the best route is. Currently they are 52/42/30. As a disabled rider (amputee, can't stand and pedal) living in a very hilly area, that doesn't really work for me. I'm wanting to install something more like 44/32/22. Perhaps something like this: https://www.modernbike.com/sr-suntour-xcm-sqr-crankset-3x9sp-175mm-44-32-22t-black-silver
I looked through the Shimano Archive for the 2005 line-up (https://productinfo.shimano.com/download?path=pdfs/archive/2005_LINE-UP_CHART.pdf) and specs (https://productinfo.shimano.com/download?path=pdfs/archive/2005_SPECIFICATION.pdf) and I believe that what I have to do is to change the front derailleur from the current 105 FD-5504-LB (triple, clamp, 63-66 degree chainstay angle) to the Deore LX version FD-M581/3 (triple, also 63-66 chainstay angle, dual pull). The rear derailleur is already a Deore LX RD-M570 SGS (long cage) and it has an 11-32 cassette. I believe the required capacity would be (44-22)+(32-11)=43 which is what the RD supports.
Note that the bike has Dura-Ace 9-speed bar-end shifters (SL-BS77) which would be set up for friction shifting on the front so I don't think that should be a problem. I realize I would also probably need to get a shorter chain and a different bottom bracket if I can't find a crankset that uses the current Octalink.
- Is there something I'm missing or would this approach of using the Deore LX FD work?
- The Deore LX FD I'm looking for is no longer produced. I know I can find one used on eBay but is there a more modern FD that's still being produced that I could use instead? I can't seem to find any that would take a top chainring >40T and are 9-speed triples.
- Is there a smarter way to do this in general? Would I be better off going with 2x10/11 speed and a bigger rear cassette? My intuition says 'no' since I'm happy with 9 speeds and I can't see it being cheaper to swap out all the components vs just the FD and crankset. But maybe I'm wrong.
- Any other gotchas to look out for? It's my first time doing a frame-up build.