The 1999 Trek 520 came with an 8-speed Shimano 105 chainring configuration of 52/42/30. This gearing is way too high for loaded trekking, even too high for enjoyable joyrides on some of the roads in my area with very long hills. After getting a new bicycle, just this year, I have a better idea of what kind of gearing this Trek should have.
I want something like 48/36/26 (the 26 is just what this config comes with - that ring will be replaced w/20 or something similar), with 70mm crank arms as well as a chainwheel guard.
The first option would be replacing just the chainrings. I've yet to find replacement 130bcd chainrings that surely have pins and ramps. I found
a "Brompton" chainring in 50t that includes a chainwheel guard, but I don't know if it has pins and/or ramps, or what speed chain it's for, or whether "Brompton" means that it won't work with other types of bicycles or not. It says that it fits 130bcd. I'd be really happy if this worked for me, because of it having a chainwheel guard.
The next option is replacing the whole crankset. For 8-speed, I've found
a Shimano FC-M361 Acera square taper crank. I would only get this if I can switch the 38t chainring to a 36t. Does the fact that Acera sits near the bottom of Shimano's line of "gruppos" mean that I should look for something different?
The next option is switching to 9-speed crankset. On the Harris Cyclery site, it
says that the only thing I need for change to 9-speed is a new bar-end shift lever, a new chain and new cassette (2nd product down from the top - Dura-Ace 9-speed bar-end shifters). Would the reason it omits a new rear derailer be, that the idea is to use friction shifting instead of indexed?
I think that I might like to switch to 9-speed, if Harris Cyclery is correct, because then I could have a cassette that goes from 11 to 34 without any jumps bigger than 4 teeth. My Trek 520 currently has a "Megarange" cassette which goes to 34 and I hate the 8-tooth jump from 26 to 34.
For 9-speed cranksets I've found:
Shimano FC-M391 Acera Square-taper crank.
Shimano FC-T4010 Alivio Octolink crank.
Shimano FC-M4060 Alivio Octalink crank.
I don't really know anything about those two different types of fastening systems (Square-taper and Octolink), except that the square-taper is appreciated by a lot of people. Which is more worthwhile to have in this scenario, square-taper or, a higher level "gruppo"?
The next option is switch to 10-speed crankset. My 2020 Kona Sutra came with Shimano Deore FC-M8000/T6010. But like the T8000 crankset, I can't find it available for sale anywhere in the USA. The only places that I can find it for sale are in Europe and they, for some unknown reason, refuse to sell this particular crankset to customers outside of the EU.
Is switching to 10-speed even possible with this old bicycle frame and, is it even a worthwhile endevour, assuming that I'll have to get a new rear derailer in addition to all the other stuff like shift levers?